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FAQs about Canopies, Tops and Housings for Lighting for Marine Systems 2

Related Articles: Canopies, Covers & Lighting Fixtures, Marine Light, & Lighting, Moving Light Systems, Marine System Components, Used Gear

Related FAQs: Canopies 1, & FAQs on Canopy/Cover: Rationale, Design/Engineering, Construction, Sealing, Reflectors, Fans, Wiring, Repairing, & Marine System LightingFAQs 2, FAQs 3, Actinic Lighting, Metal Halide Lighting, Fluorescent Lighting, Compact Fluorescent Lighting Small System Lighting,

A helpful hydraulic strut to hold up a heavy canopy.

glass tops, function, SW    10/30/12
Hi I have tried finding on your site info on glass tops, does using them stop the good light waves from reaching corals and things,?
<Can be a bit of an impediment; yes. Best to just keep it clean and dry... give it a wipe every week or so, during other regular maintenance>
is it best to run tanks without the tops,,, confused.
<Can be... better... given there's some other screening to prevent animals' leaving... and not a worry re losing water due to evaporation (and possibly spray, splash)
thanks for your help
Val Sammut
Toronto, Ontario, Canada...
<Maybe a read here: http://wetwebmedia.com/marcanopies.htm
and the linked files above. Bob Fenner>

Saltwater tank hood   10/12/11
Hi guys,
<Hi Aesia,>
I just have a quick question. I am in the final stages of beginning my journey into the world of marine care. I am making a shopping list for the tank and I have come to find an inconsistency that I can't figure out which side of the fence to sit on.
<It surely won't be the first inconsistency. It is surprising how many things come down to personal choice. The best is just to know all the information on both sides and choose what is best for your needs.>
I have read in many articles that an open top system is better for oxygenation while at the same time having the issue of escapees from not having a lid.
<This is accurate. However, if one runs a protein skimmer in the sump, and has a decent turnover rate between the sump and the display, the oxygen issue is moot.>
But I have recently read that another problem is that this allows for fluctuating salinity and temp levels.
<Running a larger heater will make up for the lost heat issue. Although, it does use more electricity that way. You surely get more evaporative cooling when running an open top system. Sometimes this is helpful as reef-tanks often get too warm from all the lighting. A solution to the salinity fluctuations is usually counteracted with an auto top-off system.>
I would like to have an open lid as I need to order a custom 60 gal tank to fit a well built antique bar that I will have waterproofed and sealed (this is really another question I have for you but I need to move my turtle (current resident sitting on bar) to take pics of it for that question. Will email about that in a couple of weeks). If I were to go with a screened lid this should combat the escapee problem but is the temp and salinity going to change so drastically? My main tank will be a 60 gal, sump 20, and refugium 20. With this much water will it matter?
<With the proper heater, temperature fluctuations should not be an issue, especially in a tank that size. Salinity will not be an issue either. Either use an auto top off system, or top off manually.>
I am shooting for 70-80 gals after set-up (this is of course in theory as this is my first marine mini biotope. Pls correct me if I am wrong. Not sure how much space will be taken by live rock). Thanks so much for ALL you do.
<I'm not sure if screen-tops are available retail yet. I've always made them with 1/4' clear netting and aluminum window screen edges. Here is a website that shows an example of the netting: http://www.bulkreefsupply.com/store/clear-1-4-screen-netting-7-x-3.html 
Also, not that it matters, but I prefer open top during the day, and a cover on at night. It is a little tedious covering and uncovering, but it makes the tree-hugger in me happy.>
<All the best,
Scott Tomko>

To Cover Or Not To Cover; That Is The Question -- 12/16/10
Hello to all with the crew,
<<Hiya Beth>>
Haven't written in a while what with one thing and the other but I've a few questions.
Question 1: I have been running Power Compacts (2 10,000 K daylights and 2 Actinics along with blue LED's) on my 125 gallon (6 foot) reef tank for years with no issues however, the colors of corals I can keep seem to be limited to green or tan and random purples.
<<Hmm'¦ You don't give the wattage, but even if these are 96w PCs, I expect this tank could use a bit more, regardless of the stockings 'and in the 10,000K range versus Actinics>>
Any other colors I get brown out. Reading multiple articles has led me to wonder if this is related to the high nutrient levels I maintain (deliberately as this is a lagoon type set up), which would contribute to a higher Zooxanthellae population per coral
<<One of several factors to consider>>
or to the fact that I have a double barrier between the lighting and the tank (moisture protecting plastic strip below lights and a glass canopy on tank to reduce evaporation).
<<Another contributor>>
Since both barriers can reduce UV lighting,
<<Indeed 'along with total output across the entire spectrum>>
and corals color up as a protection against UV light,
<<A factor, yes 'but in of itself, not the 'whole story' re coral coloration>>
would it make sense to remove one or both of those barriers?
<<In my opinion 'yes. Removal of the 'plastic strip' will increase light penetration. Removal of the 'glass canopy' will increase light penetration and arguably, gas exchange>>
Do you think this would increase the colors on for example, my Acans or Favia? (both a rather bland grey or tan with color only at the oral disc)
<<Can only help in my opinion, considering the type and intensity of your current lighting system. But as eluded earlier, lighting is not the sole answer to coral coloration. As you mentioned, nutrient control can be a factor 'along with nutrition/feeding and the availability (lack of) of key amino acids. Water chemistry is also a player here. An imbalance/shortage of bio-minerals can also cause some corals to lose color/intensity, in my experience>>
Question 2: I have an elegance coral who appears to be doing quite well but I have questions related to its feeding. I currently feed a little bit of whatever I am feeding the fish. This could be Formula 1, Formula 2, Plankton, Marine Cuisine, etc.., quite varied and something different every day but not much of it. I thought that this would be a bit more along the lines of how they eat in their natural environment but noticed in your posts frequent suggestions for larger, meatier feedings twice a week or so.
<<This is mainly if the coral 'is not' getting what it needs from your daily feedings. If the coral is feeding and doing well now, I see no need to change your methodology>>
Since I do maintain a high organic load (no skimming and very little true filtration, just random water movement), and since it does appear to be doing fine, should I just continue my current practice?
<<Sure 'for the reason just stated>>
I do 30% water changes every 3 weeks or so and am not concerned with over feeding so much. The elegance, along with the Wellsophyllia, Acans, anemones, and Favia, appear to eat everything I give them and never regurgitate so I thought I was doing ok.
<<If this is the case then yes, I would agree>>
Other possible contributing factors:
PH: 8.3 ish (varies from 8.1 to 8.3
Nitrate: 10-20 ppm
<<Some Nitrate is important to both health AND coloration. These levels are likely fine for the biotope/livestock you have, though striving to keep it toward the lower end of this range may prove best>>
Alk: 9 to 11 dKH (I do have to buffer every week or so).
Calcium: 400 avg.
Phosphate: 0 but using API and have had other forums state a not very accurate test kit
<<Might I suggest a Salifert or Seachem kit then. Or if you want to get really accurate, one from Merck or Hach>>
Temp: 78
SG: 1.024
<<I would raise this to NSW levels (1.025/1.026)>>
Thanks as always for your advice and work.
<<Happy to share>>
<<Poor coral coloration is often a combination of factors in my experience. Try 'clearing the path' so to speak, for your lighting as discussed 'and maybe lower those Nitrates just a bit (add a skimmer or some chemical filtration) and see what that does. Adding a couple more 10K PC bulbs would also help, in my opinion. You could also look in to some of the amino acid supplements available 'and/or add some Selcon to your feeding regimen. Eric Russell>>

Yet Another MH Question, heat, incl. louver use f'   -- 7/14/10
I read through the Metal Halide FAQ and am still looking for answers for my personal tank (60 gallon - 48x15x18). I have the Current-USA Sunpod 48" 2x150W fixture and, unfortunately, it sits only 4" above my tank water with the stands that come with the fixture. Given this situation, my tank has been running consistently at about 79 degrees from PC lighting up to 83-84 degrees with MH. I just bought the hanging kit for this fixture and planning on raising it the recommended 8" or so above the water. By what degree do you see this helping with the heat?
<A degree or two F.. I would leave off the MHs during the day... in the warm/er months of the year... have them on during the cooler evening hours only>
I understand that I run the risk with a glass top and high heat as well.
I'll look into getting some egg crates but will the heat melt this?
<Look for the Polystyrene variety, about 240 C... vs. acrylic (160 C)>
I assume running an open top will be fine as well, as long as the fixture is well above the water?
One last question- one of the two fans also stopped working in the fixture and am looking to replace it soon. In the mean time, do you recommend an ordinary desktop fan be placed between the fixture and the tank to cool the
fish tank even more?
<Worth using>
I appreciate your help!
Thank you,
<Welcome. Bob Fenner>

Covering a tank, without losing light    -- 10/21/2009
Hi friends.
I am looking for a suggestion on a problem I have.
<Hopefully you will find one.>
I have a 125 gallon aquarium that houses more aggressive fish than I care to be rebuked for. To my amazement, my aquarium has never looked better. I know it's blaspheme but I've had my share of Cyano outbreaks and the like that lasted weeks to months. It's all gone and even my few noxious corals all look great. The best they've ever looked. Full polyp extension etc.
One thing I have done differently since going from a reef tank to more of a fish only (with a few corals) FOWAFC,
<Hmm, many corals or few corals I would still consider this a reef tank.>
(heard of that one?), is adding not the brand name "poly" fibers, but a similar blue fiber pad in each of my two overflows so that a great deal of waste is caught in there. I rinse them out at least weekly, sometimes bi-weekly.
<Sounds great, try to keep it to bi-weekly but a ton of waste can be extracted this way when you have large messy fish.>
I also have another pad in the sump, and a black coarse pre-filter over the return pump as well. I've always had the Euro-Reef skimmer which helps, but I think this extra massive filter pad employment has dramatically helped me. Because again, I know I'm overstocked, but everything is doing very well. I also, for the record, plan on moving fish out as they grow too large for the tank. Right now, there are just several smaller fishes.
<I won't comment on overstocking in this case.>
Anyway, to my question. Sorry...
Tonight one of my Triggers jumped out during feeding time. The 6" Niger.
The biggest of the lot.
They all go crazy when the food comes out and he got a little excited in the corner of the tank pursuing some floating dried shrimp. Luckily, I happened to see the whole thing happen. He wound up on the floor behind the aquarium wedged between the wall and the frame of the stand. It was a little difficult extracting him from the floor. I had him as carefully as I could by the tail but his face or gills or teeth or something was sticking to the ground. It took a few tugs to free him but got him back in the water. He seemed shaken but not stirred. But upright anyway. Some scuffing, but I think he'll pull through. I'd like to avoid this from happening again as I enjoy watching them grow not drying up. I use halide lights so an enclosed top is out. Too much heat etc.
<This really depends on the rest of the setup, some heavy evaporative cooling facilitated by fans over the sump may be just the trick, I recommend experimenting a little bit with a thermometer in the display.>
I've heard you guys talk about egg crate plastic but I was wondering about how much light is lost and redirected out of the tank with that stuff ?
<I don't have any figures for you, but keep in mind the "egg crate" is sold as light diffuser, and it's purpose is to diffuse light, not block it.
However some light will be lost when passing through the egg crate, I assume when you speak of noxious corals that are compatible with the fish in the tank, that you have a bunch of softies, these will likely be fine loosing only a fraction of light from the use of egg crate. Do be careful where you purchase your egg crate though, the lower quality stuff is truly just a grid, but the higher quality lighting diffuser has a taper that will allow more light to end up in the tank. Also since you are concerned about light loss, please stick with the white egg crate.>
It seems at this point I will have to use something like that or it will surely happen again. Just wanted to know what the best options currently are.
<These FAQs also address your issue:
http://www.wetwebmedia.com/marine/setup/lighting/canopyfaqs.htm >
Thank you for your services,
<You are very welcome,
Josh Solomon>

Tank Hoods 9/16/09
Does a 44 gallon pentagon aquarium hood fit a 40 gallon pentagon aquarium.
<Depends on the manufacturer, but my guess is that it will not..>

90 gal SW tank - new set up Lighting Inquiry Current USA Outer Orbit 24" 150w HQI & 4 T5HO & 12 lunar LED 4/13/09
Thank you for 'tank'ing time to respond to my questions.
<Ah, it is a blast being part of WWM!>
I have been in the hobby for 9 years and have always had just a FOWLR 90 standard 48" tank. I
initially started with one anemone but when that died due to lack of sufficient lighting within days of purchase, I decided to get used to the requirements of this hobby and stick with fish only for a while. Sadly
other items took priority and my tank was somewhat neglected in terms of new hardware.
I am happy to report I just upgraded from my standard 48" 90 gal to a quarter round corner tank 90 gallon with sump. The tank came with a single mogul 250 watt MH with remote ballast but I am worried about the heating issue. I like to have my tank lit for a long period and would be concerned that the new location combined with the 250 watt would require a chiller, which I don't really want to purchase.
<Depending on what you wish to keep the lighting, followed by a chiller could be a necessity.>
I want the tank lit for 10 hours per day for the enjoyment of my friends and family that I think just come to
visit my tank not me..
I have found what looks to be a great light fixture: the outer orbit 24" MH/T5HO combo. The problem I have is that the new position of my tank is right beside my TV and my husband wants to be able to actually see the TV without staring into an offensive light so I need to use some form of 'canopy'.
<I know that feeling!>
The installation for this light claims that it should not be mounted in a canopy.
<A standard disclaimer.>
I suspect they mean the standard aquarium canopy that comes with a basic tank. I am worried about heat, and if this light will penetrate deep enough for me to keep anemone, clams & possibly some corals
when I get really brave (and have the weeks to do my research and find sources).
<You can keep any of these lighting wise with the more light needing livestock in the upper half or so of the tank...do be careful and research re compatibility. Anemones in particular do not mix well with other corals.>
The current canopy is a homemade job that is about 10" tall. I thought I could mount this fixture in the top of the canopy and it would be over open water.
<Sure, this is done all the time...you will want to add a ventilating fan to the canopy.
This will help keep moisture away from the fixture and help you with the heat as well.>
I am also worried that 24" fixture on a tank that is 30" wide is not good enough. I do like to have some 'shady' spots as well as bright spots (the ocean after all is not one flat bright area).
<Ah, you will have shadier spots, but I think the look will be fine.>
Thoughts, concerns, opinions?
<Noted above.>
Thanks again. I did search the FAQ but only found one really good post on the Outer Orbit fixture and it didn't really address my questions.
<Welcome, Scott V.>

Tank Cover 3/20/09
I have a question for you that I have tried to find the answer out now for a very long time.
I have recently purchased a 125 gallon all glass fish tank off craigslist.
This fish tank is 72 L by 18 W. This tank does not have any braces on the top of the tank making it very difficult to find a top for this tank. Is there anything that you can do or anywhere you can direct me to that can help me find a top or someone that has dealt with this problem in past.
<This is a fairly standard size depending on the glass thickness. You will likely be able to contact some of the major tank manufactures to purchase "trim" for this tank. It will give you a lip around the edge for a cover if you wish to use one.>
I very badly want a top for this tank and do not want suspending lights as I do not like the idea of suspending lights above my tank due to evaporation.
<Well, if this tank has no trim whatsoever you could always go to a glass company and have some panels cut that will rest on the edge of the tank itself (maybe with the addition of a bit of foam backing to prevent accidental slamming into one another/cracking). I would just contact a tank manufacturer as stated above, then add a canopy to the tank if you wish.>
Please help. Thanks, Jake.
<Welcome, Scott V.>
Re: Tank Cover 3/21/09

There is trim on the tank already and a lip but they do not make tops to these tanks without a brace in the middle. It has walnut trim
<Well, it leaves you with three options I can think of. First, you still could acquire new trim with the center support and replace what you have.
Next, you could just have a glass shop cut you a full length lid....they should also have the hinges needed. The third and probably best option is to add a center support with a strip of acrylic and a few nylon screws.
This will allow you to use the tops sold for these tanks. Scott V.>

Acrylic Cover and Lights 4/9/08 Hello, <Hello Mick.> First, thank you for this wonderful site. I have picked up many helpful tips in the past. <Good to hear, the site is an honor to be part of.> I plan to upgrade my aquarium setup with a new acrylic tank. The acrylic tank has an acrylic cover (of course). My question is this...can I use a normal T5 light fixture (216 Watts total), sitting directly over the acrylic cover...such as the Nova Extreme T5 fixture, but without the mounting legs? <I would use the mounting legs here.> My concern is the heat of the lamps and the acrylic. Will it warp or discolor the acrylic, or worse....melt or catch fire? As you can tell, I am a total novice, and I don't have any experience with acrylic tank or T5 lighting. Thank you for your time, Mick <These lights don't produce the intense heat in one particular spot that the MH bulbs produce, but do generate a fair bit nonetheless (any lighting will per the wattage in the bulb). Mounting the lights on legs just a few inches of the acrylic is a good idea. Not only for the sake of the acrylic, but also for heat transfer into the tank, a few inches can make a huge difference. Welcome, Scott V.>

Glass lid needed with metal halide?  -- 07/26/07 I've found so much information searching on your FAQS on the web. <excellent> I wasn't able to find a answer with the same equipment as in my tank. I ordered a Sun Pod 2x250w 14k MH fixture for my 90 gallon reef and it will be mounted 12 inches above my glass lid. Since I plan to keep SPS corals in my aquarium, will I need to remove my glass lid in order to give enough light to the corals? <The glass lid will, to some extent, decrease the amount of light getting to your corals. But how much light it will impede depends a lot on how clean and dry you keep it. Lids have a way of getting wet, salty, and/or dirty pretty fast.> As for the heat issue, I have a chiller set at 76 degrees. <You'll definitely need that chiller with the glass lids and metal halides.> Which can be adjusted as needed when the fixture arrives so I don't think I would need to remove the glass lid for the heat issue. If you guys/gals think I should remove my glass lid, I'm very worried about my fish jumping out. Any way to prevent this? <Since you have a chiller, the only concerns left with the lids are going to be of gas exchange and the lids getting wet, salt, and/or dirty. If you can manage to get good aeration even with the lids, and if you can keep the lids clean and dry, then you should be ok. But if all that becomes too difficult, there are a few other ways of keeping fish from jumping out. If the fish aren't really small, eggcrate should work. If not eggcrate, there are other similar type plastic grates you can get at hardware stores that might work.> Thanks so much again for all of your support! <No problem> Peter <Best, Sara>

MH Combo Light Fixture with T5 or PC? -- 06/08/07 Hello crew, I am currently looking at a 48" Current USA Outer Orbit 2x150W MH / fluorescent combo light fixture. I was initially looking a Coralife Aqualight Pro with the same basic wattage, but a salesman told me the quality has been going down since the company was "purchased", <Wow! This sort of notice already... The "consolidation" in our trade (and others for that matter) has done little... okay make that nothing... to serve the consumer (thus far?)> and the Outer Orbit was a better light. I think the Aqualight looks nicer, but having the ballasts in the fixture like the Outer Orbit (only on the 150W models) is also nice. <Yes, agreed> The question is, Current USA offers a version with 4x54W T5 and another with 2x130W PC. While the overall wattage is similar, I thought that having fewer stronger wattage lamps would be brighter and as a result "better", similar to metal halides. Is the brightness (lux or lumens) from one comparable to the other, and is one more efficient, quieter, last longer to operate? <Well... as both/all these technologies are extant, you can be sure there are consumers of all... and that all can/do "work"... For looks as well as function, there are proponents, adherents in each camp... I myself like the appearance of the PC's with MH... but per useful photonic energy per money spent, the T-5's are superior> As always, thank you for your input. Your site rocks! Erik <Welcome. Bob Fenner>

Retrofitting Lighting, Corallimorph sys., using WWM -- 03/18/07 Hello and thank you for this most awesome site.    <Howdy and welcome>   I have been looking through all the info, and have not been able to find an answer to this specific question.   I have a 48" All-Glass Aquarium, Inc. Deluxe Fluorescent Aquarium light.  It is listed as 120v 40w 60hz. <Yes... just one normal output fluorescent lamp of four foot length...>   I know it is way too weak for a reef tank, but was wanting to try to retrofit it.  (It came as part of a package my wife bought me for my birthday.)        Is it possible to retrofit this light?  If so, where can I find info on kits or DIY?    <Yes, and on the Net, your Local Fish Stores... measure the hood, or consider buying one of these to fit the new fixtures, lamps>   My 55 gallon tank is very new (started on 1/24/07) and I had planned on upgrading the light a little further down the road.  I purchased some LR today that has 3 mushrooms on it.  (Did not see them on rock when I bought it.)  I do not want them to die, so I was going to try to retro the light ASAP, then do lots of reading to figure out how to care for them. <Ummm, you want to reverse the timing of this behavior...> Or, is there some way to remove them from my tank and get them somewhere they will be better cared for?  (LFS)  The rock they are on is 15lbs, so I do not want to remove them rock and all.    <These Corallimorphs should be fine under the present light for quite a while... won't "grow", but won't die...>   Thank you for your help.      Gordon <... Please learn to/use the search tool and indices on WWM... This time, read here: http://www.wetwebmedia.com/marsetupindex2.htm the last tray at the bottom... on marine lighting. And here: http://www.wetwebmedia.com/corallim.htm and the files linked above. Bob Fenner>

Should I Go topless With My New Lights? Go Topless Or Not? -- 01/15/07 Good afternoon to whoever gets this. <<Greetings...tis Eric here>> Please don't let my long-windedness scare you. <<No worries mate>> I only have a few questions, but I do offer great detail...maybe too much. <<Never! [grin]>> I was hoping not to have to bother anyone, however, it seems the more reading I do, the more unsure I become. <<No bother at all>> It is truly awesome all the information your site has available, however, because there is so much, I lack enough confidence to do anything without some direction and/or reassurance. <<A common reaction...but confidence/assurance will come...with continued reading, researching, questioning...and of course, experience>> I hope you don't mind.   <<We're here to assist>> I currently have a 46-gallon bow-front All-Glass aquarium.  In it I have close to 40 lbs of live rock, 2 TR Ocellaris Clowns, 1 Royal Gramma, 1 Yellow Clown Goby, and 1 Fiji Devil Damsel.  I also have 1 Skunk Cleaner shrimp and a handful of various snails and hermits.  Now, onto my issue.  I am sadly only using the lighting that came with the tank, one 25 watt strip light. <<Mmm...>> Did you cringe? <<Only slightly>> I never intended on more than a FOWLR set-up. <<Ah, I see...but still, a bit more light will benefit the live rock and the emergent life there on>> And I honestly thought the lighting was good enough for viewing pleasure, and my proposed population of fish didn't require any intense lighting. <<This is true...but better/more lighting will also make better viewing...in my opinion>> It has been very close to a year I am in the hobby...just shy of a few weeks.  It is over a year if you add in the cycling of my tank with the LR.  I don't know if it happens to many, but I feel like expanding my horizons beyond the fish. <<Yes...does happen to 'many'>> Experience with no major issues makes all the difference I guess. <<Indeed...  Many hobbyists fail/give up the hobby in their first year.  This can be for many reasons but is often due their own impatience and lack of research beforehand.  Perhaps you are doing enough homework and making enough right decisions...let's keep this trend going, eh?>> I also wanted to do my fish and live rock a favor and get some better lighting, not to mention it is way overdue I am sure. <<No time like the present...>> So last weekend, in search of higher wattage, I came to find I couldn't get anything stronger for the hood that came with the tank itself. <<Mmm, no...not without changing the ballast at least...then likely space limitations for the higher rated bulbs>> Herein lies my reasons for writing to you all. <<Finally...just kidding! [grin]>> I purchased, with the  help and recommendation of the staff where I go (That Fish Place), a CORALIFE 36 inch Deluxe Lunar Set-up of compact fluorescent lamps.  It contains one 96 watt True Actinic 03 Blue CF lamp and one 96 Watt 10,000K Daylight CF.  It looks like 4 bulbs to me...2 of each. <<Ah yes...two 'tubes' per bulb>> It sounds impressive, and I hope it will be. <<It will be a HUGE difference from the 25w bulb for sure>> They tell me I should see my LR take off and an enhancement of my fishes' colors, plus I could get some corals/inverts requiring low to moderate lighting with this fixture. <<Agreed...on all counts>> That was a definite selling point now that I have the itch, but I am just not quite ready yet, as I haven't really researched what I could support, the care of them, etc. <<I'm liking you more and more Tiffani.  Keep this attitude/approach to the hobby and you will do fine>> So, I am not going there yet. <<Do take your time>> I have been reading your articles/FAQ's everyday any chance I get about lighting and canopies.  I obviously cannot use my current hood.  I haven't even taken my new set-up out of the box yet or anything (I am scared remember), so if information related to my questions is in there, I am sorry to have bothered you. <<You're doing fine...but do go ahead and open the box/read what little information is there re the fixture/installation>> The salesman did recommend I could purchase a glass canopy, which they did not carry for my particular tank, but I did find I can order one through All-Glass. <<Not necessary or even desired as it will limit gas exchange and light penetration>> Or, he says, I could go topless, which he does and has no problems with and prefers, but it was up to me. <<This is what I would do>> Through my research, it seems some of you recommend definitely keeping the tank covered, and some do without.  Is it a matter of preference?  Is it a glass thing? <<Mmm...more a 'type system' thing I think.  On a FO or FOWLR system the light penetration is not so important as keeping that Zebra Moray in the tank.  On a REEF system, among other things a dirty glass top can easily negate the benefits/effect of the lighting>> I realize the risks of no cover, but it seems using a glass cover isn't the best either. <<In my mind, the advantages of going 'topless' outweigh the risks>> From what the photo of the glass canopy looks like, if I use one, it appears the top isn't completely sealed as there will be openings for the hoses and things. <<Usually, yes>> The lighting I purchased has an acrylic cover, so if I go with the glass canopy, do I then not use the acrylic cover over the bulbs? <<Honestly, I would probably remove this cover as well as it will also accumulate dust and mineral deposits diffusing the light from the bulbs>> Do/could/should I just then rest the fixture directly on the canopy, or would I use the mounting legs still. <<Nix the glass top and use the mounting legs>> Can the heat from the light fracture the glass too? <<Is possible...but usually not a worry with fluorescent/PC lighting>> Any suggestions would be greatly appreciated regarding to use a cover or not? <<Have made my opinion known>> If one does go topless is evaporation really significant? <<It will increase yes>> I am sure there are many factors to consider though, i.e., temperature of the room.  I did see that some of you also recommend the egg crate covering in lieu of a canopy?? <<Only in instances where jumping fish are a concern>> Also, when I do utilize the new lighting, which I am so anxious to do, I have concerns about that too.  I obviously will have more than a significant increase in wattage.  I cannot imagine that won't affect my fish somehow, like shock them, blind them or something.  There is such a huge difference in wattage. <<Hmm...do the fish have places where they can get out of the direct light?  I don't think you need be overly concerned re the fish and the new lighting but if you wish, you can place a piece of eggcrate over the tank and rest a few layers of fiberglass screen material on this.  Remove a layer of screen every few days until all is gone...much like acclimating corals to new/intense lighting>> Like I said, it is still in the box, but there is a separate switch for the actinic and the daylight bulbs.  Do I just use one for awhile (the actinics) then turn on the other? Or is there a way to use one bulb out of the set? <<I recommend you use timers and set a regular lighting schedule (10-12 hours per day)...your livestock will greatly appreciate this.  Use both bulbs, but the separate switches will allow you to put the bulbs on separate timers.  Many folks like to have the actinic bulbs come on an hour before the other lighting, and stay on an hour after, to 'simulate' a dawn/dusk effect.  This is also useful for preventing panic among your fishes from the lights suddenly coming on/going off>> I hope that makes sense and I am not a complete idiot. <<Makes sense to me...>> I hope this isn't a dumb question, but does more intense lighting affect the water parameters a great deal? <<Astute of you to question...  The increase in lighting will affect microbial activity...much o which will be undetected/invisible to you.  The biggest effect you will likely notice is an increase in pH from the increased photosynthesis among the alga and emergent life on the rock>> I was told that my set-up shouldn't get that hot that it would affect the water temp or anything.  Is that true? <<You won't really know until you put it in place but yes, as long as you don't cover the tank the PC lighting probably won't cause a heating 'issue' though you may see a slight increase in water temperature>> And just out of curiosity, can things really just emerge on my LR, even though I have had it for one year under my current pathetic lighting? <<Indeed it can/will.  The new lighting will 'activate' many life forms that have been in 'stasis' on the rock due to inadequate light intensity to drive their life processes>> I do have a small amount of coralline algae, but not much. <<This will likely increase, though its absence is not always due to lighting>> I have more unattractive nuisance algae, which probably doesn't surprise you.  And finally, in watts per gallon...to figure that out, do I add the 96 plus 96, then divide by gallons to get a number? <<Yes>> If that is correct, then I would have close to 4 watts per gallon of lighting?? <<Agreed...but this is a poor way to measure lighting efficacy.  The differences in lighting approaches (T5 vs. PC vs. MH, etc.), the differences in PAR among Kelvin ratings and even manufacturers,  the differences in water clarity among individual systems, the differences in livestock requirements, all these and more dictate the 'wattage' required...much too complex to be simply stated as an all encompassing formula of  'watts per gallon' of tank volume.  But this is just my humble opinion>> I do thank you for your time and opinions.  It is greatly appreciated. <<A pleasure to share>> Tiffani <<Regards, Eric Russell>>
Re: Go Topless Or Not? - 01/15/07
Dear Eric, <<Hello Tiffani>> I want to thank you so much for your reply, time, much needed information, and your opinion. <<Was a pleasure to give>> I also thank you for not chastising me, and more importantly for the positive reinforcement. <<Mmm, yes...as a military instructor for six years, we were often reminded of the value of a few words of encouragement/acknowledgment of achievement...though some folks do prove they will only respond to a good rap on the nose with a rolled-up newspaper [grin]...present company excepted of course>> I try to do as much research as I can, as often as I can. <<Wise of you>> I have spent many a late night reading over your site. <<Indeed...much information to cover/digest>> I also have The Conscientious Marine Aquarist that I frequent often.  I am looking forward to thoroughly reading the sections on inverts and their selection very soon. <<An excellent book...  Might I suggest you also obtain Bob's/Anthony's book 'Reef Invertebrates' for some updated husbandry/methodology information, as well as Eric Borneman's excellent guide 'Aquarium Corals'.  There are other authors/books very much worth having as well, but these will give you a good basis for reference to start with when you convert your system to 'reef'>> Sooner or later I hope to take the reef plunge...in due time. <<Patience is indeed a virtue in this hobby>> Your support is very kind and informative. <<Redeeming to know>> I will hopefully open up that carton today.  I have learned that with my soon-to-be 3 year-old twins, things don't always go as planned, but their is always after their bedtime. <<Mmm...envy you I do not>> And, yes, the fish do have numerous places they could hang out in if they prefer a more shaded ambience. <<Excellent>> It is funny I never thought about their ability to do that.  Maybe I am not as smart as I thought.  Ha ha. <<You're doing fine>> Thank you again, not only for helping me out, but also for everyone else you and the rest of the crew assist on a daily basis. <<Is our choice/pleasure to be here>> Give yourselves a pat on the back.  Take care. Sincerely, Tiffani <<Be chatting.  Eric Russell>>

Polyurethane   1/12/06 Hi Bob, <David> In a recent exchange, you suggested using polyurethane as a sealant for wood canopies.  I've also seen other references to this on WWM. <Yes> Well, I just built a small canopy for a 3g aquarium, using 4"x1/4" birch molding for the sides and 1/8" MDF <Mmm, I really don't like this material around water... like me, it starts to swell... http://home.att.net/~waterfront-woods/Articles/Plywood.htm> veneered ply for the top.  I did 3 coats of poly, taking special care to seal the edges well.  Let the poly cure for 3 weeks.  Left some openings for airflow, but there's quite a bit of condensation on the inside of the canopy when the lights are off.  After 2 days, the top has already started to warp! <Yes, very common> In retrospect, I think the 1/8" MDF was a particularly bad idea, but I'd've thought the poly would seal pretty well against moisture. <Mmm, no...>   So I asked a couple of people about this.  At the LSWS (local specialty wood shop) they told me that polyurethane is not appropriate for high-moisture environments, and that plywood of any thickness will eventually warp unless it's marine-grade ply (which is made from mahogany or teak, and probably some special type of glue). <What did they suggest?> And a friend of mine who has extensive experience with wood in marine environments told me that the common oil-modified poly you get in hardware stores won't do it... water-based poly is worse...  The only kind of poly that will completely seal against moisture is two-part poly, which is usually sold in marine supply shops.  He says you can coat balsa wood in 2-part poly and completely submerge it in salt water with no worry. Anyway, thought I'd post some feedback/experience, maybe a note of caution for other WWM'ers. Best, -Dave <I thank you for this input. Will place/share. Bob Fenner, who has used many gallons of urethanes... and was likely lucky>
Re: Polyurethane   1/12/06
Bob, <David> At the wood shop, they suggested the marine-grade plywood.  Of course, they may have wanted to sell me some pricey marine-grade plywood. <Is expensive... but marine grade... is great... I/we made whole facilities, exhibits out of this (coated) along with glass viewing panels and Silastic years back... along with fiberglass strip cloth and hot/coating resin...> My friend (who lived on a few tons of floating teak for 14 years) said that even marine-grade ply will take on some moisture and swell over time, although not as much.   <Agreed> His suggestion was use any old plywood, and coat it with a marine-grade polyurethane.  Specifically, he suggested two-part poly (see http://www.epoxyproducts.com/lpu.html). <Yes... I do think this is best/better> I've seen some one-part polys marketed as "marine-grade" but I'm suspicious... when you think about it, a one-part poly has to be somewhat porous because it requires cures with air and water.  Two-part polys don't have this requirement because they don't need air/water to cure. I suspect this is mostly an issue with plywood and/or soft, open-grained woods... I steamed and bent a piece of birch for the front piece of my canopy, so it'll be interesting to see what happens there... Best, -Dave <Thank you for this follow-up, your thoughts. Bob Fenner>

Aquarium cover   12/31/06 <Hi Suzanne, Mich here.>     Just wanted to thank you all for your invaluable info.   <Glad you have found the site helpful.> I graduated from a 30 gal tank to a 75 gallon in August.   <Congratulations!> I'm still learning. <We all are.> I have a Percula Clown, Six Line Wrasse, Lawnmower Blenny and four Purple Chromis.  The Chromis were supposed to be peaceful, but they fight with each other constantly.  One or two is always missing a fin and is beat up looking.  I feel bad for them.  My goal is to take them all  out and give away.  They act more like Damsels that Chromis.  I am aware they are in the same family.  I got rid of three yellow tailed Damsels when I transferred from the 30 gal. to the 75 gal. because of the aggression. <Sorry to hear of your problems here.  Can be a real challenge.>     My question, though, is about an aquarium cover. I didn't want to seal the top with all glass.  I lost a six line wrasse before that jumped out of the small opening by the hose leading to the filter.   <For shame!  These carpet surfing fish are determined.  They find the tiniest openings!> Because of the oxygen exchange and the heat issue I got some egg create and custom fit it.   <Good idea.> There were NO gaps in it.  I added a diamond goby three days ago.  He jumped out the FIRST night!!!!!!!!   <First day is not uncommon.  The fish is new to system and can be easily startled.  Best to cover tightly the first week.> He HAD to have gone between the squares in the egg crate and he was about three inches long and seemingly too big to fit.   <A very determined fish.  Sorry to hear of you loss.> How do you figure that!?!?!?!   <I hear ya!> I am now topping the egg crate with the gutter guard that I put around my overflow pipe.  This HAS to stop anything from jumping out shouldn't it??   <If there's a will, there's a way!> Or should I go with glass, since I do have a trickle filter.  But I am worried about the heat. <I understand your concern with glass.  I think you are wise with your modifications.  However, when introducing a new fish that is known to be a jumper to a system, it is always best to cover the top very tightly the first night especially, better the first week or so.  If you have glass I would use it as a temporary measure, not a long term solution.  I think/hope what you have set up will be sufficient for longer term use.>       Any feedback would be appreciated!! <Hope that helps.  Best of luck.  -Mich> Suzanne

Lighting upgrade   12/14/06 I love your web site I check it often and is my first place to look for advice! A Ballast burnt out on my JBJ CF 4x36 light. The second ballast is the same age and who knows how long it will last, maybe it is time to replace/upgrade the fixture. <Perhaps> My tank is an 58gal oceanic reef-ready, dimensions are 36.5x18.5x21.5. I have a few soft corals and would possibly like a bubble tip anemone. <Read about this mix... on WWM... elsewhere> I do not know if MH is in my budget, what size do I need, would a 175 MH work? <Yes> Can you recommend a retro kit that I can build into a hood? <Mmm, don't know much re such... would, as with nearly all  such "gear" choice questions, suggest you posit this on a few of the larger, specialized hobby BB's... e.g. Aquarium Frontiers, Reefs.org...> If that doesn't work for me then does it make sense to buy a cheap CF or T5 fixture similar to what I have. (I then may not be able to keep an anemone.) <Mmm... I would not buy, use any "cheap" lighting... gear period. Too dangerous> The cost of 2 new Ballasts + 4 bulbs is close to the price of a new fixture, so why not get a new fixture? I believe T5 would be the better choice here. If I choose MH, I would need to build a hood. Do you have any good references on building a hood? <Yes... see OzReef.org re and Antoine's article here: http://www.wetwebmedia.com/marcanopies.htm and the linked files above.> I can build the case, I am more concerned with extras (paint, fans etc.) needed to make it work in the Saltwater tank environment. <Can be done... a worthy project. Bob Fenner>

Egg-Crate Cover and a Snowflake Moray Eel   12/14/06 Morning fish friends... <David> So I have read every piece of literature on your website concerning snowflake eels.  My 200gallon semi-aggressive predator/large fish tank will revolve around my eel.  I had precise fit glass tops made to prevent the eel from possibly escaping... however, this seemed to prompt the temperature of the tank to increase to 32oc over 3 days. <Yikes... need some (small holes?) venting> Only two small blue-yellow tailed damsels are in the tank at this point.  I removed the glass covers (what a waste) and setup a fan on my sump. Overnight, I have dropped and can likely sustain a water temperature of about 26/27oc.  I realize this is within the safe zone, but a little high.  I'm positive I can maintain this temperature without fluctuation. I considered a chiller, but my aquarium room has no suitable place to vent the hot air exchanged.... And will likely further heat my 90 gallon reef tank (also sitting at 27oc).  I'm in Calgary, Canada and it's December... would never have thought this would be an issue.   <Oh yes... aquariums, water... thermal addition, retention... through lighting, pumps... appreciable> Anyhow, I am exploring a small air-conditioning unit for the room in the next few weeks. <Mmmm... might be necessary... at least expeditious> Anyhow, I need a cover for my tank that will allow air circulation.  I am planning on getting sheets of white egg-crating to fit securely on the rim within the top of the tank opening.  As well, am having 2x4 wood blocks cut... one block for each end of the lid cover to add weight to the cover as well as to elevate my PowerCompact lighting.  I can barely fit my index finger through the holes in the egg crating and therefore figure there's no way my snowflake eel (picking him up today from the store) will fit through as he is about as thick as possibly three of my fingers. <Yes, this will work>    I have one 2x65 watt 24" Corallife PC fixture (about 10lbs) and one 2x95 watt 36" Corallife PC fixture (about 15lbs).  I'm actually surprised that I don't hear about or read about more people that are using egg crating as a cover for their tanks... <Is a "stock" item in many parts of the aquarium world... and as you state, virtually unknown in others... I strongly suspect your note here will go a long way in reducing the latter> would prevent most non-small fish from exiting the tank, great for ventilation, easy to add most foods... cheap!! <Yes... do look for the stronger Styrene variety... lasts much longer w/o breaking... both easy to cut with a "Jigsaw" and a fine blade> Questions: 1)  Using the 2x4's to elevate my lighting to further allow air ventilation under the lighting and over the water.  It will just be about an inch from each side of the lighting fixture on the wood... the lens protecting the bulbs shouldn't be in contact with the wood... <Correct!> and even then, the lights don't heat up that much... they both have two fans on them.  This wouldn't be a fire hazard or anything, would it? <Could be with direct contact...>   I mean, people have wood canopies, etc...   Just checking... <These often need insulation...> 2) Snuggly fit plastic egg crating weighted down by 4 - 6 2x4's that are 24" long... plus the light fixtures on top of these... should be more than adequate to prevent a snowflake eel too thick to fit through the holes of the egg crating??? <Yes>    Of note, there is about 4" of room between the top of the water level and the bottom of the egg-crate cover... I'm thinking further to my security plan... the eel wouldn't have as much 'push' or 'thrust' outta the water to be able to seemingly poke and push with the water level dropped as such. <Agreed> 3) I also have a loose piece of egg-crating covering my overflow box that covers the top to prevent fish from going overboard.  The loose egg-crating is not fastened so as I can clean in there... however, my output manifold (water from sump pump back into main display... manifold consists of a T and about 8" of 1" pvc on either side of the T with spray nozzles) rests on the egg crating with a downward force... as the flex hose goes over the side of the tank via an elbow to the aforementioned T. The water pressure on the manifold provides weight to the egg crating cover.    Even though it seems snug... now that I have typed this... maybe I need this modified. <Perhaps> While I think of it.  My retailer has in a batfish.  It's big and black with red tinges... <Mmm... a Pinnatus... exceeding difficult, rare to stay alive in captivity> It's possibly the most magnificent fish I've seen for sale over the years.  I wouldn't dream of introducing this fish to my tank now... but in a couple of years when my tank is fully cycled and operating smoothly... would this batfish make a good roommate for my snowflake eel? <Read on my friend> I am also considering a Antennata/Radiata/Zebra Lion (one of), angel, tang, Foxface, maybe a wrasse... If I don't think of a hundred more questions this month... have a great Christmas! Dave <And to you and yours. Bob Fenner>

Aquarium-safe wood sealant  11/16/06 Hi crew, <David> I'm planning to build a wood canopy for one of my tanks.  I'm thinking of using 1/8" veneered ply for the facing, to keep the cost down, but I'm concerned about chemicals from the wood (formaldehyde) ending up in the water via condensation or off gassing. <And rotting by way of moisture, heat...> What do you recommend using as a sealant, both to protect the wood from moisture damage and to prevent contamination of the water?  I've Googled for "safe wood sealant" and came up with some products that claim to reduce off gassing-- do any of you folks have any experience with these? Thanks, -Dave <Urethanes, polyurethanes, Varathanes are my faves... come in various colors, reflectivities... readily available from "hardware" stores. Bob Fenner>

Re: Aquarium-safe wood sealant  11/16/06 Bob, you don't see any problems with off gassing/leaching from polyurethanes? Don't want to end up with any 3-toed fish! <Heeee! No worries... once cured (about a day) there are no such issues. BobF>

Lighting Question  - 09/14/06 I recently purchased a used Oceanic bow-front 90 gallon reef tank (53"L x 18"W x 25"D).  The previous owners retrofit the Oceanic hood with the following lights: * (4) 18" VHO bulbs (30W each) * (1) 400W metal halide single-ended bulb <Okay...> I'm not sure if you're familiar with the hoods for Oceanic bow-fronts, <I am> but the design requires me to remove the entire hood every time I need to get my hands in the water. <Yes> To get easier access, I plan to install some rigid plastic legs that will hold the hood up above the tank, leaving a 12" gap between the bottom of the hood frame and the top rim of the tank.  If I do this, the VHOs will be about 18" above the surface of the water, and the metal halide will be about 17" above.  Will this still allow enough light to penetrate into the water to support a variety of clams, softies, and LPS corals? <Mmm, for the more high-light-intensity species, I'd arrange these more directly under the single MH... otherwise should be fine (though bright!)> Thank you in advance, Steve in Denver <Welcome. Bob Fenner in San Diego>

90 gallon Reef MH question, heat   9/5/06 Bob,     I have read a lot of your articles on WWM about the  Metal Halides and everything else.  I currently have a 90 gallon all glass  aquarium with a corner overflow.  I'm currently using a Aqualight Plus  Fixture contain 2 10k whites and 2 actinics all being 96 watts with the standard  wooden canopy above the lighting and the tank.  The tank without the use of  a heater stays around 77-78 degrees.  I'm playing with the idea of getting  the New Outer Orbit lighting system that contains 2 150w 10k  HQI MH and 2  130 watt PC Actinics.  With the tank being a taller tank and liking the  shimmering effect of the MH I wanted to know if there was a way to include the  canopy at least on the outside without worrying about the heat issue. <Fans... a chiller...> I  don't mind having an open top canopy but I would like to at least have some type  of a canopy so that I don't see the light fixture.  I was thinking about  installing two fans in the back on the canopy to blow the air out from under the  lights as well as drilling some holes on the outside of the canopy to allow air  flow thru the fixture itself that does contain an 3.5 inch fan always. <Better to blow in and out...>   I  just don't really like the fact going somewhere and seeing the lighting fixture  and the light peeking thru the sides between the light and the top of the  canopy, but I do understand that MH put out a lot of heat but I wasn't sure if  these HQI lights with the new design of ballast put out else heat.  But my  main issues is being able to put the light system on the tank without it being  too much light for the corals, LPS, Calms, SPS and zoos and polyps. <Won't be here>   And  having some type of a canopy around the sides so the tank looks complete like a  piece of furniture not just a tank please let me know Thank you Drew <Can be done... will likely need a chiller. Bob Fenner>

Re: 90 gallon Reef MH question.  9/6/06 With the MH being about 7 to 8 inches off of the water is this ok, or is it going to cause the light to be too intense for the tank. <Need to elevate this high or higher for light distribution and safety reasons... see the manufacturer's recommendations re>   Do you believe that with fans I can keep it cool or more than likely I will have to have a chiller, which I really don't want to purchase at all. Drew <More than likely the chiller will be needed if using 250 watt units or higher. Bob Fenner>

4ft T5 Lighting Placement   8/31/06 Hey guys.   Great web site! It has helped me out a great deal in the past.    <Good>   Just a quick question.      I have just picked up my new 4ft T5 with 4 tubes for my brand new 4ft x 2ft x 2ft tank (FOWLR). The light came supplied with small (but not small enough) stands to mount the light on. However the hood (which I have installed fans in, thanks to your FAQ's suggestions) will not fit, due to the light being too high with the side stands fitted. Will it hurt if I simply place the light straight on top of the tank, with lids etc fitted? <Mmm, likely will be okay... do take care to not knock the whole thing in... If it were me/mine, I'd fasten some sort of "wings" to the ends to prevent this> If this is a "no no" can I simply use some strips of wood placed at either end of the light to elevate the light unit off the glass? If so, how high do you think? <Oh... yes... an inch or so... maybe with some sort of extension in the front to diminish the blinding effect on viewers, of the light there>   Or do you have a better suggestion?       A big thank you from down under!   Garth <Mmm, not really (haven't quite woken up...), other than fashioning a whole new canopy. I'd try what you have listed above first myself. Cheers, Bob Fenner>

Light + Heat = Frustration  8/2/06 Greetings to each and every member of the crew. <And to you.> My question today concerns some difficulties in keeping our reef tank cool.  We're hoping for 79 deg., but 80 would be OK.  Having a hard time achieving that and wondering if something is wrong. This is a 40 gal. tank - 36" long, 24" deep, 12" wide.  We have a glass canopy.  Lighting is a Coralife 36" Aqualight compact fluorescent light fixture - w/two 34" long 96 W bulbs (10,000K daylight bulb, 96W actinic).  This fixture has 2 built-in cooling fans.  Accessory mounting legs were installed that raise the fixture off the canopy 2".   The daylight bulb is on 11-12 hours per day; the actinic a total of 6 (2.5 in the morning, another 3.5 at night).  We have central A/C, but rather than try to keep the entire house at refrigerator temp. levels, we closed off the room with the tank (a small room, perhaps 11 x 11) and put in a window A/C unit.  The room temperature maintains at 71 degrees.  Shades even kept closed because it's been so hot.  We have also been keeping the aquarium stand doors open and the cover off the sump so that the sump is exposed to the cool room air.  At present there are no sump fans. <With an ambient of 71, your lighting should not be raising the temperature that much.> My question is - daily tank temps go from 81 deg. to the high 83 deg. area.  I hear the light fixture fans, but does it seem excessive that mid-tank depth temps are in that area in a darkened 71 degree room?  I'm wondering how to tell if the fans have become compromised in some way.   Would you expect to see a tank that's 10-12 degrees warmer than the room under the circumstances I've described?   <Not with your conditions.  I'd make sure your heater isn't coming on, may be defective.  You may also have a powerhead overheating.  Unplug pump(s) one at a time for a day or two and see if your temperature comes down.> Given the relatively dark, very cool surroundings of the tank, doesn't something seem wrong?  I certainly can't imagine going to MH lights at this rate. <If you have a custom wood hood with the light fixture inside, your problems may lie here.  There won't be much room, in this regard, between the fan intake and the wood canopy.  If this is the case, you will need to have a hole drilled, at least the size of your fan diameter, that will align with the fan on the light fixture.  A decorative chrome guard can be placed over the hole.  Another area to check is the amount of dirt/dust on the fan blades.  Most fans are held in place with four screws.  Remove these screws, with the power off, and clean the blades with Q-Tips and alcohol.  The motors in the mini fans do not have any more power than necessary to turn the blades.  Excess weight, in the form of dust/grime, on the blades can result in a slower RPM of the unit and impede desired CFM of the fan. A coincidence, since I have a 40 gallon minireef with the same wattage lighting system and I have no heat problems.  My ambient (room) temperature is 76. I am not using a Coralife system.  My lighting unit is completely enclosed in acrylic whereas the air is forced through the housing and nowhere else.  Hope this helps you out.> Thanks in advance for any help you can provide. <You're welcome.  James (Salty Dog)> Laura

Re: Light + Heat = Frustration   8/3/06 James - Thank you for this answer.  We feel sure the solution is cleaning the fan blades.  We have already ruled out a problem with the heater, and will do a test of the powerheads one by one if the fan cleaning doesn't do it.  However, we think that's it.  The fact that you have a similar-sized tank and do not experience these temp problems with ambient room temp of 76 degrees confirms that something's wrong.  (That's what we had our central A/C set for, and couldn't keep the tank cool enough, which is why we closed off the room and put in a window unit.)  We had suspicions about the fan lights, but would never have thought about a messed up powerhead supplying heat, so that's great info even if not the culprit this time.  Thanks again so very much for your input. <You're welcome.> Have a wonderful day. <And you, also.  James (Salty Dog)> Laura

Lighting, cover/canopy questions   8/1/06 I have a 215G, 29" tall,  aquarium that I would like to set up as a hardy reef, with more of an emphasis on fish.  Really the only corals I plan to keep are a few mushrooms and perhaps a few other corals which can withstand higher nitrates and low lighting.   I would like to keep a radiata lionfish and a smaller moray as two of my few fish, along with perhaps a maroon clown.   I was looking at the 72 Inch Orbit power compact light fixture, which produces 576 watts, and was wondering if this would be enough lighting to enable me to keep the mushrooms, while not making the lionfish uncomfortable? <Should work here. Particularly with providing rock overhangs for the Lion to get out of the light> Would you have a better suggestion concerning the amount of light I should use? <Mmm, all are posted on WWM>   Also,  I was wondering what your suggestion would be for the aquarium top since I would need to make it escape proof for the moray. <A heavy canopy that entirely covers the edges... holes in the top or side for a fan blowing in, one blowing out for heat control>   I was hoping to do a glass top, <See here: http://wetwebmedia.com/marcanopies.htm and the linked files above> I will have a separate sump and refugium which should allow for oxygenation of the water.   How much would the glass top decrease the amount of lighting reaching the aquarium inhabitants? <Depends on the make-up of the glass and how clean it is kept... can be very little to considerable. Best not to use such a device>   When people do eggcrate tops, how do they access the tank for fish feeding or other chores without completely removing the eggcrate? <They do the latter... remove it> Obviously glass tops have hinged access panels, but I'm not what I would do if using eggcrate.   Thank you for your reply. Kevin Jackson       <Read on my friend. Bob Fenner>

Building a Canopy 7/27/06 - I need to build an aquarium canopy for 125g salt water tank. What all materials do I need to get? <Can probably get by with wood, screws, glue, and a long hinge.> Do you have a diagram I can go by? <No, we do not, but you might search on Google or your favorite search engine for such a thing.> <<Ozreef.org, RMF>> Thanks! <Cheers, J -- >

I was just wondering if UV light is blocked by Plexiglas more, less, or not at all more than glass.  7/14/06 <Mmm... well both can/do... which one more? Depends mainly on thickness: http://www.newton.dep.anl.gov/askasci/chem00/chem00539.htm but Plexi wins in "oranges to oranges" comparison with "ordinary" types of glass> My question is really more of would it be better to have a glass top over  my saltwater aquarium or glass? <Safer?> I assume glass would be easier to keep clean but I was just wondering if I could use Plexiglas for a smaller tank I have just setup for saltwater? <Mmm... yes> Thanks. Oh and by the way I love this site you guys do a great job with even the simplest questions. Mike <Few are simple to/for me... I want to render something complete, useful here... The "best" cover/s for marine systems are actually none... Discounting increased evaporation and the very real possibility of livestock exiting stage up, there is generally no concern for avoiding/filtering UV A, B... And (hopefully) the lamps/fixtures folks use have lamps that produce negligible amounts of these wavelengths, come with shielding of their own... Is this (semi)clear? Please read here: http://www.wetwebmedia.com/marcanopies.htm and the linked files above. Bob Fenner>

General Husbandry; Lighting'¦and I.Q.   7/4/06 This is probably a dumb question , <I'll take your word for it.> I'm a newbie, but maybe the only dumb questions are the ones people are too afraid to ask: <I used to think that 'till I started working at a police station, anyway'¦'¦..> Is the result of combining  multiple sources of light a cumulative thing ? If I have two 40 watt lights on top of my aquarium does that mean it is getting 80 watts of lighting or is it  getting 40 watts ?? <80 watts'¦'¦however in aquaria you should be concerned with lumens not wattage.> Thank you. <Anytime.> Rick Horton <Adam J.>

Canopy / Fixture.. retrofit?   6/18/06 I have a 55 gal saltwater tank, with a 4x65watt PC Orbitz lighting fixture (with moonlights).....and I bought a hood today, but it will not fit over the fixture......is it possible for me to take apart my $250 Orbitz fixture and make a DIY retrofit into the hood? <Mmm, yes> Have any idea if anyone's done this? <Oh yes> I'd like something to go by. I figured I could cut a hole in the side of the canopy for the fans, and mount the reflector, clips and lights all to the top of the inside of the canopy, run all the wiring to the side and down around the back. But I am a newbie at this so do tell me if I'm about to light my house on fire...LOL ....thank you <I would take all this into a friendly LFS (or secondly to a local marine club meeting) and ask for their direct input. Can be done. Bob Fenner>

To Cover or Not...Let Your Tank "Breathe" - 06/18/06 Hello Crew! <<Hi Pedro!>> I plan to add metal halides to my 75g tank, I have now 2x96w pc + 2x56w T5, and want to add 2x150 MH on canopy.  Don't know if to go with fixtures with built in UV glass filtering pendants or to use the All-Glass Versa Tops with do it yourself HQI sockets.  Will save some money with the second, but will I block too much light and build up heat? <<Yes to both...having the glass on top of the tank will trap heat/slow gas exchange as well as reduce light penetration due to the "mineral buildup" that will form on the heated glass due to its proximity to the water.  It is much better to have the UV filter on the light fixture/pendant rather than on the top of the tank>> Nobody in Florida wants more heat.  I will have 2x4" IceCap fans blowing across the glass tops with all the lights on. <<Won't make enough difference>> I heard that the glass tops reduce evaporation which I like, but  will I give up too much light for too little evaporation and add more heat? <<Yes>> Is egg crate a better option? or no top at all?  Just the canopy with the fans that can give me surface movement and deal with the evaporation? <<The egg crate material is fine if you have fears of jumping fishes, but I prefer "no top at all"...lets the tank "breathe">> Pedro  Velasquez <<Regards, EricR>>

Perspex/Acrylic covers, effect on light   5/27/06 Dear Bob Thanks very much for your web site it is like our bible. <Mmm, I'd settle for a good, handy guide...> We have a question for you. Can you substitute a sheet of 3mm Perspex as a cover glass instead of using a sheet of glass. Will Perspex diffuse the actinic blue light or is it best to use glass. Kind regards Peter and Marilyn Smith <Some acrylics do more selectively absorb and phase-shift these wavelengths of light... The best cover over/twixt the water and light source is actually none... Acrylic will do, but I'd like to add the proviso that it can "catch on fire" if heated too high... like by being too close to metal halides. There are posted measures for the degree of loss here... posted on the Net. Bob Fenner>

VHO Bulb Proximity to Acrylic? - 04/18/06 Hello, <<Howdy!>> I've been reading a bunch on your site, (great stuff by the way!!) <<Thank you>> I'm bumping up from a 55glass to a 125 acrylic gal tank for my reef. <<Cool!>> My question is how much clearance do I need to allow between the VHO bulbs and the top of the tank?  I know the MH gives off a lot of heat, the VHO not as much, what is a safe distance? (I'm planning on using 6- 48" bulbs across the top (2' wide) <<You'll want to get the bulbs as close to the water as possible for maximum effect/efficiency.  A standoff height of about 1/2" or so above the acrylic will provide sufficient airflow around the bulbs.  I have known folks to lay the bulbs right on top of the tank...but I prefer not to do so>> Take care, Mike <<Cheers, EricR>>

Finding A Suitable MH Reflector - 04/11/06 It has been quite some time since I had to go to the all knowing WWM Crew with a question, but since this is a continual learning hobby, I have returned! <<Indeed it is...for me as well...welcome back>> I am rebuilding my 65g reef tank due to a forced relocation.  I have 4x 96w VHOs and 2x 250w MHs.  It isn't hard to fit all the lights in the canopy (19"x37"), but I had to seriously mangle the reflectors to put them in the first time. <<I'll bet>> Basically the MH's parabolic reflector had to be partially bent closed from their ~13" width to about 8" and I had to cut the VHOs' reflector in half to about 5" each because I have 2x VHOs on either side of the centered MHs. <<Not so much an issue with the VHOs, but this would seriously affect your "spread" on the metal halides>> I want to put a "less mangled" reflector in the hood this time. What do you think about a simple 36"x18"x2" reflector instead of the mix-match I have now? Do you know where I can get such a reflector? <<Indeed I do!  PFO has a 36" parallel reflector with dual mogul sockets and "shelf" to mount your VHOs.  I have two of these over my 8ft tank.  Check out an example here:   http://oceanencounter.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=OE&Product_Code=P3PRW2MS&Category_Code=RSC  ...if you have any questions about the reflector, call Vince at Ocean Encounter...a very helpful individual>> Thanks (again) for the help! -Jeff <<Always a pleasure, EricR>>

Equipment/Lighting/Egg crate light obstruction  4/6/06 Hi guys-  <Hello Ed> My library now numbers 28 books and I still find myself turning to you for answers.  <Excellent, a well stocked library.> I am planning a reef tank - 90 gal. LR/LS + refugium. I will be keeping SPS/Clams and a few LPS. The following lighting has been recommended: " would get a fixture with two 150 watt double ended or two 175 watt  single ended MH lamps versus one metal halide. And, I would be sure to get one  that used VHO or T-5 actinics instead of PC. Lunar lights/LED's, I would take or leave." <My personal choice would be two 150 watt 14K HQI's.  No other lighting is really necessary unless you want a dawn/dusk effect.> The fish I have selected for ultimate inclusion includes a number which  have been described as jumpers. It has been suggested that to contain them I should use egg crate.  I  cannot find any information on the reduction of light which will result with the use of egg crate.  Would you recommend increasing the wattage to 250? <Why not a glass/acrylic top?  Why waste energy or add heat to incorporate an egg crate top. Thanks,  <You're welcome.  James (Salty Dog)> Ed

Re: Equipment/Lighting/Egg crate light obstruction  4/6/06 Dear James:  <James is good enough.> Thanks for your speedy reply.  <You're welcome, luck of the draw.> I was under the impression that the use  of a glass or acrylic top was discouraged as it impeded gas transfer and  increased heat retention.  <Using a sump will cure the gas exchange and fans are definitely going to be needed to exhaust heat from the canopy.> I was hoping to avoid the expense of a chiller  as the ambient room temperature is 70 to 72 degrees, the light fixture I had  selected (but not yet purchased ) incorporates fans and the was to be  mounted on legs with the tank top remaining open.  <Should be fine, but as with all high output systems there will be an increase in water temperature, but I'm thinking your system (with two 150 HQI's) should run around 78/79 with your ambient room temperature of 70/72. Thanks,  <You're welcome.  James (Salty Dog)> Ed

Lighting/Canopies  - 03/28/06 Hello again,  <Hi> Read the FAQ in the canopy/hood section and just want to make sure I interpreted everything correctly. Plan on buying a 90 gallon with an oak stand and oak canopy. After reading about covering the tank itself, it seems that you propose no glass covers for various reasons.. greenhouse effect, salt creep, light refraction etc. So my question is won't the water that will be evaporating be trapped by the canopy? <Will be humid to say the least.> I plan on mounting a 6 bulb T5 fixture inside the canopy. Is there anything I need to do other than painting and sealing the inside of the canopy? <It will require a cooling fan to exhaust this air out of the canopy.  It's a DIY project and the fans are inexpensive.> Anything I should watch out for in buying the canopy? <I prefer a canopy where the entire top opens for ease of cleaning, etc.> Anything I should look out for in buying the T5 fixture? <No.  James (Salty Dog)> Thanks for your help.  <You're welcome.> Jim McDonald

Use of Canopy   3/24/06 Hello Wet Web Staff <Hi Bonnie - Tim answering your question today!>, I am considering upgrading my lighting system on my 30 gal. reef tank.  I currently have power compacts.  I've noted that some of the HQI systems I am looking at state that they should be used with a glass canopy to help cut down water evaporation.  I always thought that any tank must be well ventilated.  I would think by placing a glass canopy over the entire top surface of the tank/water, that this would be bad.  I'm worried that the heat would build up in the tank from the lights. If you could tell me your thoughts/comments on this, it would be appreciated <I completely agree - the tank should not be covered with glass as this will result in a heat build-up, lack of gas exchange and also reduce the amount of light entering the aquarium.>.  Thanks.  Bonnie

Lighting/Canopy   1/27/06 Hi, <Hello Kathy>   Newbie to the whole lighting thing, but I have been reading the posts on lighting so I do understand a lot better now. Just a quick question if you don't mind.  I will be getting an 80g acrylic bowfront next week and the guy made a canopy for it from solid wood and had his lights attached to the top of the canopy w/these metal round clip things that you screw to the canopy and then pop the light in the circle holder and it pops right in, he's done it this way the whole time he had this tank and I noticed a lot of green algae residue in the canopy which he apparently wants,<Why would he want algae residue in the hood?> I believe they're compact fluorescents but I don't know how much wattage and such.  He's been doing this for over 10 years and has a 125 gallon also, and has some bright lights in that canopy without a fan or anything.  From what I've read it seems that I should get 4x96watt lights, but I was wondering should one of them be the actinic since I would like a little blue color to the water? <Yes, you would want to if a little blue is desired.  Will help coralline growth also.> I was considering at some point getting some hammerhead coral or other easy to care for corals that don't require a ton of lighting and would like to keep my coralline growing. (not to mention having some algae growing for the tang) What do you think? <Sounds good, but I wouldn't encourage nuisance algae growth for the tang.  Much better to feed Ocean Nutrition Seaweed Selects or a similar product.> I have a yellow tang, clownfish, fire gobies, coral beauty and flame cardinal, not to mention the hermit crabs and 2 different kind of snails.   Thanks a ton for your help! <You're welcome.  James (Salty Dog)>   Kathy

MH upgrade and tank cover   1/18/06 Guys,   Have a 48x15x24 DAS 75 gal with angled front corners. Upgrading light from 2 96w PC to MH of some type. I have a few fish, leathers, Shrooms, and RBTs and clams which are needing way more light but doing OK so far. Have the same setup about 2 years. Looking at 36" (because of in tank filter/skimmer) PFO or Hamilton 2x- 150 W HQI plus actinics. The fish are jumpers and need some type of covering. If I make a wood cover with cutout on top and about 8" off water surface and sit the fixture on top of it, and add a fan to the cover to draw air across the water, work? <Likely so> Or is it best to hang pendants and cover the tank another way? <Could... a raised border on the edge...> Worried about heat buildup, tank runs around 80 deg now. Hoping the 150's will be enough for Acropora, clams and anemones and move my soft corals to the bottom or will 250's be needed? <If it were me, I'd use two 150s... but do know of folks here who would go higher... not worth the trade-off in other maintenance, risk IMO> Thanks and hopefully see some of you in Irving soon. Darren <... Maybe. Bob Fenner>

Wood finishing, plumber's tape for threaded connections, painted backgrounds, whew! Hi Guys (a generic term that includes the female members of the crew ;o) <Watch this...> I have searched WWM & couldn't find a relevant answer - hopefully I've not missed! <We'll see... or add to it> Just a quickie re finishing the woodwork for my new 24" cube - I will need some sort of finish on the veneered panels that I have now got for the new tanks cabinet and open topped hood but I am not sure what would be most suitable, I have been looking for some sort of polyurethane varnish type stuff but have so far drawn a blank (maybe its just called something else in the UK?).  The main area for concern will clearly be the hood woodwork as this will be the closest to the (salt) water & thus more chance of particles of finish (or some sort of reaction leading to leaching of nasties) entering the water column (clearly something to be avoided if at all possible (however I believe in planning for the worst - comes from working for the UK government I guess lol!!)) Any pointers to a suitable finish would be more than welcome. <Polyurethanes are fine (durable, non-toxic once cured, attractive), though I am a bigger fan of Varathanes (as you speculate, perhaps a "Yank" (formerly colony) term... These come in different reflectivities (I like the less shiny), and are even more durable> Would you be able to confirm my suspicion that PTFE (plumbers) tape will be fine for sealing my new closed loop system? From what I can gather this should be fine and nicely inert. <Is... though I am a bigger fan (here we go again) of using 100% Silicone (the same material/el used for making glass aquariums... for thread to thread connections... makes a nice flexible joining, and allows for easy unthreading if needed later on... and "makes a seal" rather than allowing salt creep over time. Bob Fenner> Ok just 1 other question ;o) <Oh!> I also need to paint the back (outside obviously) of the tank black to match the weir - I am planning to use enamel paint - Japblack I think the brand is (do you see any problems here?) <Am unfamiliar with this term> - will I be OK just to go ahead and paint this or would I be better running some sandpaper or such over the area to be painted to provide a "key" or rougher surface for the paint to adhere to? <Mmm, I have used latex or water-based in-door wall paint here... sans scratching... to good effect...> Sincere thanks as usual in anticipation Cheers   Chris

Question about glass canopies... 01-10-06 Hey, first off, I find a ton of useful information on your site. <Glad to hear it.> Keep up the good work. By running across your site, I've taken the plunge into the saltwater department! I've got everything up and running, however I'm having trouble finding canopies to fit my 55gal tank with a center divider. I've got an Emperor 400 taking up one side of the tank, and a Coralife Protein skimmer on the other along with hoses for the Eheim canister filter. I've talked to the guys at the LFS and they told me to go to a glass shop and have hoods custom made. They claim it will save me money. I've thought about buying the All glass-Versa tops, however I don't think that they will fit because the protein skimmer is sitting an estimated 3 inches in the tank, and the back strip on the versa top adds approx 2 inches. What do you suggest to do in my situation? I can't wait to get fish and rock in there! <I personally do everything I can to avoid glass tops.  By not having a glass top you will increase gas exchange. The main reason I suggest avoiding glass tops is that they end up blocking up to 50% or more of the light's spectrum and penetrability. If you do still choose to use glass tops I would suggest going to a glass shop. Travis> Thanks, Kevin

DIY light hood  - 01/03/2006 Hi. <Hello. John here with you this evening.> I'm planning to build a hood with 2 250W MH and 2 96W PC bulbs. My question is, what type of reflector is best? <For the halides or PCs? For the halides, the shape of the reflector is critical - there are a number of variables. Do check out Sanjay Joshi's interesting work on this subject- the most relevant of which is here: http://www.advancedaquarist.com/issues/july2003/feature.htm . Bear in mind that all double-ended bulbs must have a piece of protective glass installed below the bulb to block damaging UV radiation - it may be easier / safer to purchase a fixture.> I have read that some people  paint the inside all white, some black <Surely not black!.> Others use a mirror type  reflector and some polished aluminum. thanks for your advice. <You're welcome! Best regards, John.>

DIY canopy Resources  12/20/2005 Hey Crew, <Hi.> I really want to buy a new 10 gallon tank to house some Dwarf puffers. <Okay.> I was thinking about making my own canopy to save some money, as the tank itself is only $10. <A worthy project.> I was wondering if any fluorescent light would do the trick, I won't be housing any live plants, the light would be just for lighting up the tank. <Yes this tank just housing fish needn't have any special lighting. Just enough for the fish to see, whatever meets your aesthetic qualifications. Normal Output fluorescents are just fine.> Also , if there are any good links you guys know of how to build a canopy. <<I would start by searching through google also visit some of the aquarium chat forums for ideas, try ours here: www.wetwebfotos.com/talk. Also try Home depot/Lowes for good deals on cheap "shop"  lights and wood parts/tools.> Thanks for all the help! Have a great holidays! <You as well, Adam J.>

How Do I Get a Tank Cover - 12/13/2005 I have an older tank- not sure of the manufacturer, its probably an All Glass or Perfecto.  Please let me know if you have any advise on how I can put a lid on it. <Easiest would be a Versatop type. Could also take your tanks measurements and shop around online/locally. Probably a "standard" 125, so it should be fairly simple.> Thanks, Brian <Surely. - Josh>
Re: How Do I Get a Tank Cover - 12/13/2005
Thanks Josh, <My pleasure.> The problem I'm having is that there is no cross beam and all tops seem to need that. <Ahh, I see.> Do you know if there is a kit I can put on to replace that cross support? <Not that I've seen. You would need to contact a manufacturer for that I think. Even if you're not sure exactly who made it, they don't have to know that;) Just make sure the dimensions are correct. What is this top for (intended purpose)? If just holding lights, Have you considered suspending them? Can also make top covers just to close off escape routes (eggcrate or some such).> Thanks, Brian <Quite welcome. - Josh>

Netting for a top/cover 11/24/05 A couple of quick ones guys - as I am unable to provide a hood for my aquarium (due to siting, light fixture etc), would it not be possible to secure a little netting of some kind over the top? <Yes>   I know it sounds a tad crazy/makeshift and I've not heard of others doing this, <Many folks do... that have suspended lighting, naught twixt their water surface and such... some folks I've seen have rigged really neat tilted trampoline type arrangements to allow jumpers to flop back in...> but would it pose any problems IYO? <Mmm, a bit more evaporation...> (I was hoping to perhaps include a known 'jumper' you see!) <Most all fishes, invertebrates are...> Secondly, I have Percula Clowns, Green Chromis, a Royal Gramma and an Andaman Damselfish.  With these fish in mind, should I conclude with a Yellow Tang or a Long-nosed Butterfly fish IYO?  Many thanks in anticipation, Steve Morse. <Mmm, please see WWM re Systems, Compatibility for these, other possible livestock. Bob Fenner>

Paint inside canopy  9/5/05 Hi crew. I was told to paint the inside of my canopy with exterior white high gloss acrylic latex, then finish off with two coats of polyurethane. After applying the paint I looked over the FAQ's. The paint says it provides mildew resistant coating. From what I read this is bad. Do I sand down all the paint and restart, apply a different paint over the existing paint, or will the poly seal it to be safe. Thank You, Terry <The two coats of Polyurethane will seal the mildewcide from contact... Am a big fan of urethanes... Bob Fenner>

A short simple question: fence height required to prevent these fishes from jumping 8/14/05 Hi! I want to leave the top of my reef tank open and build a fence out of Plexiglas or buy the pre-made Giesemann rim (which is 6" high). What height you think should be the fence to effectively prevent these fishes from jumping out of the tank? Would 6" be fairly sufficient? I believe I read about it once on WWM but can't find it anymore... Yellow tang Ocellaris Lawnmower blenny Green clown goby (Gobiodon atrangulatus/histrio) Firefish (Nemateleotris magnifica) Many Thanks!!! Dominique <Of these, the biggest, highest jumpers are the Firefish and blenny (at times)... they need a good few feet of rim actually... to absolutely restrict the possibility of leaving the system... The best rig I've seen here are screens that encompass the entire top... Bob Fenner> Re: A short simple question: fence height required to prevent these fishes from jumping 8/15/05 But wouldn't a screen restrict the light or is there a product/material I do not know of that would not filter the light? Thanks! Dominique <Yes... life is a series of trade-offs, compromises... all types of screening will reduce light transmission. Bob Fenner> Paint for Inside of Canopy 8/1/05 What type of paint might you suggest for painting the inside of a canopy white, and perhaps the same for inside the stand to help reduce moisture being imparted to each?  How about a white, one part epoxy paint (saw this at Home Depot, by Behr). <Should do>   Wouldn't the epoxy style paint provide a nice hard, durable finish? <Yes> I also ran across another idea by someone else (on ReefCentral or some such) - a Behr white paint coated by a Minwax polycrylic clear gloss?  Any general ideas?  Thanks. <Epoxies, water based latexes and polyurethanes are my faves. Bob Fenner>

Going topless or no... tank covers I'm trying to decide whether or not to purchase VHO's and mount them directly to the top of the canopy, and having no top on the tank, or using a lighting source that can lay on the tank top. My question is how much does the glass tops that come with these aquariums affect light transfer? Are you significantly better off leaving the top off of a tank for light transfer? <From my experience, glass tops will often be covered in "salt creep" (dried salt) within a few weeks. With that said, the light is going to be blocked unless the glass lid is constantly cleaned. Glass tops will also trap heat inside the aquarium and possibly raise the temperature of the aquarium significantly. However, Glass tops will keep fish from jumping out of the aquarium. Overall, I would not recommend using glass lids for aquariums. You would be much better off mounting the lighting to the top of the canopy. This would also make it easier for aquarium maintenance for the fact that you would not have to take off the lid and lighting to have access to the inside of the aquarium. Take Care, Graham.>

Tank top/lighting question 6/9/04 hello friends!   <howdy!> just a simple one for ya': <Okey-dokey> I currently use the 1/4 inch (greenish tint) glass top that came with my tank to set my 110w pc fixture on. I have access to quality acrylic/Lexan at my work and could rout it to size. Would making a custom top out of this material (I would most likely use 3/16 or 1/4 Lexan) allow more/less filtration of  light to enter the tank, or be better for it's inhabitants? Hmmm... yes. There are two things at odds here: light admission in general, and UV admission specifically. Glass or Lexan will have various admissions of these two param.s. Many/most that allow  a lot of light in still often reduce UV severely (not good for corals). You need to see the mfg specs top decide on any of these random products> I want to maximize my lighting obviously, and don't think I'm willing to go topless for fear of "Gumdrop" the clown jumping out. thanks, I appreciate your time and willingness to help us all. Erich <always welcome my friend> 30g glass 15g sump, CAP 1800 return 4"sand -fine 40lbs live rock cs90 overflow urchin skimmer JBJ Versailles 110w pc lighting Millennium 2000 HOB filter -no media 1 Xenia (fingers pulse again.... hooray!) 4 hermits 5 small colonies of zoos 1 colony Shrooms 1 small (for now) gold maroon clown 1 cabbage leather frag 1 Galaxea frag  (lots o' room) ;) 1 medium meat coral 1 banded coral shrimp 2 Turbos *will be adding more zoos and Shrooms <the Galaxea, Corallimorphs and zoanthids are all quite aggressive and noxious... enjoy them in this tank that specializes in them, and do resist any more of the weaker/incompatible species (like Xenia here). Best of luck! Anthony>

Looking for a hood I have an old flat back hexagon tank that measures 48 1/2 x 18 1/2 x 20 1/4 high.  I think it is a 55 gallon tank but don't know for sure.  I think it is made by Oceanview Aquarium Products.  Where can I get a hood for this tank?  Any suggestions?  Thanks < You could try a google search for the manufacturer and see if there are any suppliers that may still have a hood that will fit your tank. Or you could try and "marry it from another tank. Just take the dimensions and see if there are any currently available hoods that may be the right size. Try eBay but it may take a while.-Chuck>

Tank lid I have an aquarium with two glass lids that totally cover the top of the tank. Is it ok to have the tank pretty much sealed all the time?  <Not a good idea to have the top completely sealed. CO2 needs to be expelled from the water to help keep ph levels up along with a good air/water exchange. If you are using a sump/wet dry, then this will do that for you allowing you to keep the top sealed. James (Salty Dog)>

To Cover or Not to Cover, That is the Question - Or Is It? Hello Crew or Eric R., <<Hello, Marina here.>> In Tuesday's (05/24/05) FAQ, someone posted a question  "Wrasse Behavior - Jumping, Freaking And Hiding (Oh My!) - 05/23/05" and in the question the writer stated that he has the top 100% covered because the wrasse likes to jump. Eric R. then responded with <Mmm...not sealed I hope...possibly covered with egg-crate or similar?>  <<Yes.>> My question is why not 100%? Why use the egg-crate? <<Actually, those are questionS, not one question. And the answer lies in a couple of areas of concern for reef aquarists. First being O2-CO2 exchange; this exchange is greatly hampered if the tank is covered in such a way as to create almost a seal. Using something that does not allow fresh air to come across the surface of the water means that this exchange won't take place here. If one is running a wet/dry trickle filter, then it's a non-issue. However, many folks have eschewed this technology in favor of that which does not encourage this exchange. The other issue has to do with heat gain, again a problem in closed reef systems. Glass not only does not allow heat to escape, it creates a greenhouse. Higher heat means lower O2 saturation. Why eggcrate? Because it is chemically inert (unlike aluminum or brass window screening), relatively inexpensive, and very easily cleaned and configured to fit any system. Neat stuff to work with, actually.>> I'm asking because I'm currently running a 100% glass covered 150gal Oceanic RR tank. What am I doing wrong now?  <<Ha! You sound like my father-in-law ("Ron!" "What'd I do now?"), and I KNEW we'd catch you! Actually, not knowing anything else about your setup we cannot say that you're doing something wrong. But if I catch you then I will. <wink> >> Thanks in advance.  Stan <<You're welcome Stan. Now don't let me catch you doing something wrong!  Marina - The One Who WILL Catch You If You're Doing Something Wrong>> 

Finish Used on Wooden Cabinets and Hoods I am building a cabinet and hood for my 29 gal reef tank out of solid oak. <Nice> What sort of finish do you recommend for these items that is non-toxic to the inhabitants of the system? <I am a huge fan of polyurethanes... in whatever choice of "reflectivity" of finish> I was planning on a typical wood stain covered with an epoxy varnish, with just the epoxy varnish (no stain) inside the cabinet where the sump will be located. Do you have any thoughts/suggestions on this topic? <I do... what you have in mind will definitely work... render the wood waterproof, protect it from rotting, be chemically inert. Bob Fenner> 

Tank top I have a tank that I bought used. I was told that it is a 220 gallon tank. The problem is I do not who makes the tank and I need to find a lid for it. It has that center divider so it makes it difficult to get one. I have found ones that fit but I have overflow boxes on the back of the tank so there is no support to hold the lid on. If there were tracks on the divider I could make it work. I realize it would be difficult to tell me who makes the yank just by the PIC I have enclosed but I need help. Please help me. The dimensions are 84"x24"x24". Thank you. The tank looks a lot worse than it really is. It has been setup for 4 weeks and is cycling. <Try white light grid or buy the plastic trim/hinges from your LFS and have the glass cut to fit.  Craig>

Odell 30gal hex tank (out of stock, biz, top-less) I have a Odell tank that needs the glass top. I've searched every where and can't find one do you know of any places that may stock them? If so I would like to know.                                                                  Thank you Cory <I would make a template out of paper (even newspaper will do) and take this to a glass shop and have them cut two pieces for you... and show you what they have to offer as "hinges"... or build one yourself out of a "pinched" bead of silicone rubber. The material for the back area (that you can cut to fit in heater, airlines, power filters...) can be had for 1/8" glass from a larger fish store. Bob Fenner>

Glass covers Hello. I just have a quick question on removing the glass covers over my reef tank.  I have a 75 gallon reef with mostly soft coral (colt, xenia, Shrooms, zoo's, etc). I have a retrofit 4X65 watt power compact lighting setup in my canopy. About 5-6 inches above water.  Should I remove the glass covers? I am worried about splashing and dog hair (yellow lab)?  Any worries or suggestions?  Mike <Hi Mike.  I am assuming you mean the glass covers on the tank, not on the lighting fixtures.  No worries with the dog hair.  I also doubt splashing will be an issue if you are careful.  If you will sleep better at night, you can fashion makeshift covers for the lamp sockets to protect them.  Best Regards.  Adam>

- Dealing with Jumpers - Hi to everyone at Wet Web Media <Hello to you.> I contacted you last year regarding a problem I was having with my lovely gobies preferring the living room floor to the comfort of their tank!  After loosing two gobies in rapid succession and subsequently reading up about their habits on your website I decided to call it a day as far as goby keeping was concerned! I lasted about 5 months before deciding the tank (or should I say the sand) just wasn't the same without one.  I racked my brains to think of a way to keep the goby in the tank and think I have managed to find a solution.  My current goby has been in the tank for 2 months now and so far (touch wood) is thriving - the sand is sparkling and he is quite happy to swim round all day with the other inhabitants and gobble up brine shrimp. I know you have had many e-mails from people with the problem of jumping gobies so I felt I should contact you with my idea so others may benefit from it! My problem was that I had many different sized cut outs in the back of my hood to allow access for the many tubes and pipes from filters, protein skimmers, heaters etc. and I assume it was these holes through which the gobies made their escape! I purchased some blocks of children's modeling clay, which is soft and pliable and can be molded into any shape, and made sausages and balls of the correct size to block up each of my holes.  I then wrapped each one in black polythene (cut from black dustbin liners/refuse sacks) and then with black electrical/insulation tape.  This ensured they were waterproof so would not dry out and also matched the black hood.  Each little package was then stuffed into the appropriate hole!  as far as I can see there is now absolutely no way for even the smallest fish to get out! So far this is proving successful but it has only been 2 months and my first goby lasted 3 months before making a nocturnal dive onto the floor!  It will just be a case of time will tell, but even then how am I to know if it was my hole blocking that stopped any escape or a very contented goby who made no attempt to escape!  Suppose I will never know but that doesn't really matter - so long as the goby does stay in the tank!! If it doesn't then I really do give up! Thank you very much for listening (reading?!), I hope this suggestion may be of help to any other goby lovers. <And thank you for sharing.> Gemma <Cheers, J -- >

Use of aluminium reflectors? HI Crew, <Hello Bob> On my Juwel tank, the fitted lights come with optional reflectors (which appear to be polished aluminium). <Yes... very nice units> As the lights are set very low in the hood, and directly above the water surface, I am concerned about the condensate getting back into the tank and giving a toxicity problem? <Me too> I called the supplier, and they told me that the reflectors would be "fine for marine use", but might "tarnish a bit from the salt" Hmmm? <He is steadfastly wrong here> I'd like to improve the lighting efficiency, but I'd rather add more light than do anything silly.......it's just that they are soooooo easy to fit, and they are also not too expensive.... Any comments? <I would NOT use aluminum/aluminium in or around marine systems> regards Bob (UK)  UK.. hence the "aluminium" for you US folks, I know you call it  Aluminum   :--) <A metal by any other colour. Bob Fenner in the colonies>

- Eclipse III Hood Problems - I am ready to move on from my Eclipse 3 system. <Seems a familiar theme today.> Right now it's sitting on top of a Sea Clear 30"L x 12.5w x 24H 40 Gallon acrylic rounded corner freshwater aquarium. I have the heater set for 78 degrees, and my two 24 inch lamps are on for about 8-10 hours a day. The reason I want to scrap the hood is despite what Sea Clear said about a perfect match, water condensation keeps dripping down the sides of the hood and then continues down the side of my tank. If there is an solution you can suggest... whether it be a modification to the existing hood or purchasing a new hood/filtration. <No suggestions that I can think of... probably not a marriage made in heaven, this hood and tank.> I have been looking at the Eheim Ecco/Pro canister filters, but if you have any suggestions I would really be grateful. <The Ecco canister filters are very nice - well designed.> Thanks! -- S <Cheers, J -- >

- Eclipsing the Eclipse - Hi all, my wife and I both love your site and try to keep up regularly. We have had moderate success these last 2 years keeping a 29 gallon saltwater setup.  It is in one of those eclipse systems by Marineland.  You are probably familiar, they have all the lighting and filtration in the hood.  A terrific concept but we are beginning to suspect not well designed for saltwater. <Yes, you are correct... you win... a brand new Eclipse system... what? You don't want it? They are a good enter into the aquarium hobby, but not made for upgrading.> We are able to only keep very hardy fish such as damsels and clowns and a few others.  We've tried a flame angel twice without success.  Anyways, we are positive it's gotta be water quality with the lack of protein skimmers etc. <Quantity and quality - the two are joined.> One other VERY disappointing result is our sand.  It started off great the first 6 months, very white, like the nicest beaches in the Caymans.  We both loved the sand.  However, over time, it was taken over by red slime.  We tried the yellow powder (can't remember for the life of me the name) and it helped somewhat, but in the end, it's a real mess to clean up by hand.  Again, I'm sure bad water quality. <Among other things...> So, we think we are ready to move up to a bigger system.  We have the room, the time, the money, and the desire and are considering tanks in the 125 gallon and higher range. <Ahh wonderful.> My questions are these: 1.) We are considering placing all the filtration equipment in the basement, about 10 feet below the tank.  Is this wise? <It will be quiet in the room where the tank is - that much you can depend on. Do take steps in the basement to deal with moisture, water spills, etc. Other than that, many folks wish they had the luxury of this option.> Can we do our water removal and additions from our basement as to not have to stand in front of a tall tank with buckets and hoses all the time? <One of many benefits.> Obviously, siphoning would still be done. <Sure, no worries.> 2.) Given our bad luck with sand, can we steer clear of any bottom material all-together. <If you want, but I think with some research and planning in advance, you can avoid these problems in future systems.> I have noticed this at my LFS who keeps a very nice 300 gallon setup in this manner.  Nothing in the bottom, just lots of fish and rocks. <Many folks do... think the fish seeing their reflection in the bottom glass is a bit problematic for the fish's mental health... best to at least paint the underside of the bottom panel if you choose this route.> 3.) At my LFS, the few display tanks with sand appear to have at least red algae in the sand, not to the degree we had, we had slime.  Is it that difficult to prevent even under the best of conditions? <Not difficult to prevent if you understand the origins/causes - read here: http://www.wetwebmedia.com/bluegralgae.htm > 4.) Without bashing any particular aquarium manufacturer, are my experiences with the eclipse system common among those who try to keep saltwater in them? <I think so - again, tank was designed to bring folks into the hobby, not be an end-all-be-all system for everyman. Most who use these realize at some point that they won't be building the reef of their dreams in an Eclipse system.> Thanks again for services. <Cheers, J -- >

Hood weight ?s Bob, I had a bad experience with my 125G (ALL-GLASS pre-drilled) FOWLR the other day. (It cracked and emptied about 1/3 out before I caught it.) The tank was only about three weeks old and just started putting a few fish in.  <What a nightmare> I think it was my stand because it seemed to be coming apart at the seems literally the wood was coming apart from each other in the right front hand corner and it cracked in the back right hand corner. And another thought about this is I built my own hood out of pine 1x8 for the sides and front and a 1x12 and a 1x8 pieces of pine for the top. this is a suitable amount of weight I know but is this to much for a canopy to be or what amount is too much for the 125G? <The hood/canopy is not to blame... it's the stand itself and/or the surface it was placed on> I ask because my LFS is replacing my tank and stand for me but I don't want to put the hood on again and it crack the tank. My wife and our carpet can't take this again. P.S. The hood was/is level on top of the tank thanks so much (and your book CMA is a great read. Waiting for the sequel) Brian Schwartz <Thank you my friend. Don't worry about the hood. Please do read about stands here: http://www.wetwebmedia.com/tksstds.htm  Bob Fenner>

What to Use for a Cover Material? Hi, just need to know what type of base I should use to set my power compact fixture on top of. I know one option is glass and I am not sure of acrylic, but any other suggestions on different materials would be helpful. I just want to make sure that the one I use does not somehow absorb any of the lighting intensity or affect the spectrum. And should I buy a piece that covers the whole surface of the aquarium or do you think it would be better to just get a piece that will protect the light? I have an aquarium with a width of 13" and the light fixture is 6". Thanks so much. <I prefer to use glass over acrylic. Acrylic tends to bend/warp over time and can even appear burnt by intense lighting. Glass does not have these same drawbacks, but both will affect the intensity and spectrum of your lighting system. Be sure to clean either of dust and salt creep often, at least weekly. -Steven Pro>

Egg Crate Material Reference Lighting Hi Steven, Just a comment about using egg crate material to cover the tank instead of glass covers. I read somewhere a few years back, that an enterprising student studied the effect of egg crate material on light and discovered by turning the egg crate upside down (opposite of the way they use it in elevators and office buildings) it increased the fluorescent light intensity by almost 30%. Don't know if its true, but I thought I would share. Paul E. Proue of St. Joe Beach, FL <It is definitely true. Egg crate has distinct top and bottom sides. If you look closely you will notice that there is a slight taper to the plastic. Used one way it blocks out light, the other way it focuses the available light. -Steven Pro>

Re: Egg Crate Good Morning, just a quick question about using egg crate. I read that it focuses light therefore increasing light intensity. Right now I am not using any cover at all, I have my 2X96watt lighting fixture on top of the tank with an acrylic cover on the fixture. So am I worse off without the egg crate since I am not getting the benefit of the increased light intensity and having the risk of fish committing suicide by jumping out? <Yes... better to trade for these advantages and put up with increased evaporation, heat loss> Is there any problem or con you can think of from using this product? If I use it should I keep the acrylic lens on the lighting fixture or take it off? <Leave it on, except when you're "in the tank" working> Do they sell this product at stores such as Home Depot? <Yes. Bob Fenner> Thx, Angelo

Fish with Suicidal Tendencies Hello all: <Hi there! Ronni here answering a few questions this afternoon.> I have set an egg crate on the opening of my 125G tank to hopefully eliminate the screams that my wife utters when she sees that a fish has decided to take up trampoline vaulting. The openings of the egg crate are approximately 1/2" square. Well, wouldn't you know it, my canary wrasse executed a perfect jump and found its way to its untimely demise. <Ugh! It's amazing how acrobatic some of these guys can be! My kids call this committing Sushi'¦> I would appreciate any suggestions that you may have, either to wrap the egg crate with something so I can drill smaller holes, or the use of some other material for the top. I still need to provide some sort of ventilation, as the tank can get warm during the So Cal summers. <Possibly try some of the plastic canvas that's available at all craft stores and some of the larger chain stores. You can get it in different size sheets and if you can't get one large enough to cover the opening on your tank it can be hooked together easily with zip ties. The holes in it are small enough that a fish can't possibly get thru but it should still allow plenty of air circulation. And it's completely safe to use, even inside an aquarium.> Thanks, Mitch <You're welcome! Ronni>

Plastic Canvas for tank cover Ronni: Thanks for your prompt reply! <You're welcome!> I just want to be sure that I get the proper material. I am trying to envision plastic canvas...for what purpose is this used so I can try and explain to store personnel if I don't readily see it on the shelves. Mitch <It's used in crafts to do cross stitch or embroidery with yarn. Do searches on eBay or the web for Plastic Canvas and you should find a bunch of listings so you can see a picture before going out to buy some. It's very inexpensive, an 8x10 sheet should only cost about 40 cents. It's usually found near the other cross stitch and embroidery stuff in stores. Ronni>

Top or not? I'm having a lot of trouble finding consistent advice on weather or not I should have a top on my tank. I have a 125 g reef tank, with an oak canopy top. In the canopy, I have mounted some power compacts. My tank has glass covers over the water. Am I loosing light needed by corals by having the covers on? Is it safe to take off the covers? Will salt and spray damage the lighting fixtures or the bulbs? There is 4 1/2" between the lights and the water surface. Is this enough? I need help! Thanks! Bob Bachmeier <<Hmm, a tough call... on the one hand, all the items you mention pro and con... in addition to worries over heat, water loss and livestock jumping w/o a cover are so... On the other hand, is it worth the concerns to do without a cover between lights and water? For the extra intensity, reflection, phase shifting (through a medium of different optical density)...? Yes, IMO, if you can discount the jumping, combat the evaporation problems, and prevent too much salt creep, electrical contamination, corrosion... it IS better to have nothing between the light source(s) and the systems surface. Bob Fenner>>

Hood I have purchased the all-glass oak trim 29-gallon aquarium from the Pet store and am planning to set up a marine and coral tank. What hood will I  need to purchase? Thanks, Kathleen <<Hmm, well, you could look into the SHO hoods by Perfecto.... or retrofitting (to fit a skimmer) an Eclipse top/filter combo. (by Marineland)... or ordering a top with lighting from one of the aquarium lighting companies (Hamilton, Champion, even ffexpress.com)... Or, if you're so inclined and handy, even building your own top, incorporating the lighting (for me, I'd go with some 5,500K "white" and some actinic) and making what you want in the way of service ports to clean, feed the system...Bob Fenner>>

Acrylic Cover Bob, I would like to cover my soon to be reef tank with acrylic to prevent vapor from getting to my lighting. I have been told that there is a type of acrylic that is UV admitting. Is this true or will regular acrylic suffice. Thanks. Regards, Tony Tognetti <<Hmm, don't know of any... If it were me, I'd rig up some protection of the lighting, and not cover over the top... and account for the evaporation through clean, freshwater replacement... Besides phase shifting the spectra of all the light (not just the U.V portion, placing an acrylic, glass or any material of different optical density) will also reduce transmittance... significantly. Bob Fenner>>

Glass Tops Bob, I don't think that it's because you're getting old so much as me. It's been about 25 years since I took physics class. BTW there was also Van De Graaf that was a renowned cryptologist. I rewired my lights this morning without too much trouble. This got me to thinking abut something else. I have a 75 Oceanic. I use the glass tops that came with the tank to reduce noise and evaporation. I'm wondering if I should leave at least one of the four panes off for gas exchange. I haven't seen this discussed anywhere. What do you think? Marty <<Worth a try... also for better light transmission (intensity and quality wise)... as long as there's not much risk of your livestock launching themselves out... or the management of water and heat loss too onerous. Bob Fenner>>

Re: Glass Tops So I have new project for this weekend. Give my lights a siesta or a hiatus or something after I do my sparky imitation. What kind of cryptic name is "Van de Graaf"? <Oh, it's/he's the man/scientist who gets credit for the invention of the "generator" (as in Van de Graaf Generator) of electricity... Now, I'm really starting to feel old...Bob "the ex-physics H.S. teacher" Fenner>

To paint or not to paint Hey Bob  I am about to build a stand for my 105 gallon show tank. Heavy duty construction 2x4 and 4x4 framing and solid white oak covering and canopy. The question is : I was wanting to stain it and poly-urethane it. Is this a bad idea considering the possible flare up of fumes later on if the house was to get hot or the canopy was to get hot from the lights. And would salt creep really make it look worse after a while.  I think it would look good just sanded and treated but would look great stained and sealed. Any thoughts on the subject would be appreciated. Kevin Johnson <<I definitely would seal the top/canopy in any case... and polyurethane's are fine, as are Varathanes... and come in less glossy finishes nowadays... And lastly, there are parts for separating hot components from the wood itself... and simply Mylar type products to install inside that serve dual duty as reflectors of light, deflectors of heat... use them. Bob Fenner>>

Designing Canopy Bob, I am designing a canopy for a tank. The tank is a glass tank. I am looking at various materials for the cover to be made of. (Glass, Lucite, Plexi-glass...) Also using Power Compact lighting. When reading the specs on a few of these they filter UV. Is this going to be a concern for the health of the life forms in the tank down the road?  Can you recommend the best product for the job also? Mark McCrary <<Hmm, for the canopy? I would use wood or plexi... and not worry about UV filtering effects... as I would coat the inside of the structure with reflective material (Mylar based). But, do be concerned at the get-go/planning stages about heat deflection, removal... with spacing of fixtures from the canopy walls, reflective materials, vents, fans if need be and seawater damage to the fixtures, fittings.... and do consider having nothing between your lamps and the water interface... i.e. no "top" between them. This is what I assume you really mean by "a cover"... I would use none. Bob Fenner>>

Paint for aquarium tops Hello Bob. I will soon be refinishing the inside of my oak plywood aquarium hood. It covers a 55 gallon marine tank and the old varnish is deteriorating. I'd like to use a non toxic epoxy or acrylic coating but paint stores are reluctant to recommend anything. Are swimming pool paints, acrylic and epoxy, safe to use here? I want to be certain there are no hazardous substances such as fungicides present in the paint. If you have any info on this subject I would appreciate some help. Thanks. <Good question... don't know about the CR (chlorinated rubber paints) or pool epoxies... would/do use Varathane products... try looking these over... cheaper than pool products, do last, look good... Come in stains, colors... Bob Fenner>

Mylar encased in acrylic? Dear Mr. Fenner, I feel so fortunate to have your web page and the chance to email you. I never want to take advantage of your generosity. Please tell me if you feel I am doing so! <Will, would do so> I need to clear up one thing though. In your last response you suggested applying Mylar encased in a thin acrylic to coat the inside of my new canopy. The store I ordered the canopy and lighting from told me they would affix the Mylar for me but changed their mind. That was no problem, so I went out searching for the product myself. The only Mylar I found (after days of calling and searching) came in sheets. It would be big enough to cover the inside of the aquarium. My question is if you would suggest tacking it down with an adhesive then applying a water proof clear acrylic paint over top of that? Or should I be searching for a different kind of Mylar material all together? <The latter... do contact the local "acrylic, plastics retail companies in your area... and ask re thin sheets of "mirrored closet, or wardrobe door" material or such... This product is ready-made and easy to cut into pieces (thin enough, it can be scored and snapped like thin plate glass... this is what you want. Sorry for the confusion.> I have another week before the canopy is ready so there is no need for a speedy response. Best wishes, Josie <Be chatting my friend. Bob Fenner>

Paint Hi Bob, <Anthony Calfo here realizing that I picked a bad week to stop sniffing glue<G>> Is it OK to use gloss spray paint on a canopy over a marine reef aquarium??? <No untreated... a two-part epoxy (tub and tile enamel) would be a lot safer. All would be best with a cured coat of polyurethane. No paint is the best solution. Exterior, Formica...interior, anodized aluminum reflectors and the like> Jeremy

Aquarium cover and overflow size I am building a 90g partial wood tank and was wondering if I should put a piece of plastic or glass over the top opening even though I am putting a 6" canopy on it just not sure what to do here. And any help would be appreciated.  <a glass canopy may still be necessary if for example you are using metal halide lamps that need UV filtering and protected from splash> Oh one more thing I put in a overflow box for my trickle filter and was planning on using 11/4" bulk head fitting will this be enough for say a flow of 600gph or so I'm sure it will but any thoughts. Thanks, Eric <that will be close or not big enough if you actually get 600pgh to the top of the tank. If you are only getting something closer to 400gph to the tank because the pump max is 600 against the head pressure on return from the sump, you may be just fine. Anthony>

Jumping Fish, Tank Cover, Reflector Hello there, I decided to remove the eggcrate grill covering my 55g tank's top. I noticed that the PC lighting made a cool looking shimmering effect. I also noticed that the white eggcrate reflected a lot of the light away from the water. <Eggcrate have a top and bottom. Take a close look and you will notice that the sides of each square have a bevel to them. You want to orient it so that the bevel works to focus your light.> Should I keep the eggcrate on? <I like them.> I'd like to leave it off, unless that shimmering effect is unhealthy for the fish and anemones <No, just fine for the animals.> (3 FL Condys, and a bubble tip...I'll be getting rid of the Condys in time). I have a yellow tang, Kole tang, cinnamon clown, 4 damsels (4striped, 3 striped, and two yellow tails). Are any of these known jumpers? <Anyone can jump.> I currently have 2x55w PCs (two more on the way) hanging off the inside top of my oak canopy...I drilled the clips that hold the bulb into the canopy and snapped the bulbs into place, then took some metal-like yarn and tied the ends of each clip together....just in case the bulbs slipped out of the clips, the wire would catch it...I don't know if this will actually work, but it gives me peace of mind since they are now just hanging over open water (3.5 to 4 inches over the water...hard to get an accurate measurement). I am saving up for reflectors, but right now I have aluminum foil reflecting the light back to tank. Is this OK/safe to do for the meantime? <Sure, have seen it done many times.> I came across a FAQ in the archive and Bob mentioned to someone something about using Mylar or Mylar sheets or wardrobe mirrors or something like that for "something", but that "something" was never stated in the question (it was a reply). Was Bob suggesting using this reflective material as a light reflector? <Yes> Could I use pieces of cut mirror as reflectors? <Yes, but rather heavy.> Oh, I realized the other day that my 55g tank is not really a 55g tank. If I use the dimensions/measurements of the outside of the tank, and divide by 231, I get 55 gallons. But when I measure the inside of the tank, it actually comes out to about 40 something gallons. Do tank manufacturers label their products based on inside the tank measurements or outside the tank measurements? <Outside measurements.> And last, do I use the manufacturer's "55g" label when considering lighting needs (e.g., 4 watts per gallon for 55g tank equals 220watts) or my own calculations of actual in tank capacity? <The manufacturer's labeling.> Very last, does this make a difference in calculating for live rock stocking? <No, everyone uses the manufacturer's labeling for convention.> Thank you again, Randy M. Yniguez, MA <You are welcome. -Steven Pro>

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