Hole In Bottom Of Tank…Missing Bulkhead – 02/08/08
Eric - are ya there? Linda from GA here.
<<Hey there Linda! Yes, I’m still here…>>
It's been a while.
<<Indeed it has>>
I want to purchase a used 75-gal drilled tank from someone who bought the tank but is uncomfortable about it being drilled and has decided to go with a smaller tank for freshwater. (!?!?!)
<<Hmm… Although I prefer drilling the side panels when possible, many-many hobbyists have bottom-drilled tanks>>
Anyhow... Underneath this particular 75-gal, there are two holes - one has a bulkhead that connects to the drain which flows into the wet/dry and the 2nd drilled hole has no bulkhead...just a hole. Doesn't there need to be a bulkhead for each hole?
<<There does, yes…else you won’t have a “sealed” attachment point for the plumbing. The wide flange of the bulkhead also provides some strength to the hole>>
I noticed this tank came with a lot of PVC, so I am not sure how the previous owner hooked it up.
<<Most assuredly used a bulkhead fitting…>>
How do you run PVC thru this return hole without it leaking without a bulkhead?
<<You don’t…you “will” need to replace the bulkhead fitting. You can measure the diameter of the hole to determine the size bulkhead needed. Likely this will be either a 1” bulkhead (1.75”-hole), or a ¾” bulkhead (1.5”-hole)>>
Thanks so much.
Linda
<<Always welcome. EricR>>

Bulkhead question of day 10/23/07
Crew,
<Scott V>
Does the rubber O ring of a bulkhead go on the inside glass or does it go between the nut and the outside glass? Or does it even matter? Thanks!!!
Ben
<You are very welcome Ben. The gasket needs to go on the opposite side of the nut, regardless of whether you put the nut side of the bulkhead on the inside of the tank or the outside of the tank. Putting the gasket against the nut will still allow water to pass down the external threads of the bulkhead. Thank you and have fun with your set up Scott V>

Plumbing/circulation, will this work? (Diameter) 2/18/07
  Thank you humbly in advance, I'll take my fifty lashes happily if this has already been answered before somewhere else.
<You asked for it...>
I have searched WWM and its archives looking for a chart or something that is the definitive answer to probably the most popular question "How Much Will My Drain/Overflow Flow".
If you have something like this then great but if not perhaps a chart with bulkhead sizes (1",1 1/4",etc.), how much they can drain (max), how much they will drain (real world est.), and how much they should drain( quietly). This would eliminate many boneheaded questions from people such as my self. please disregard this if you already have this up somewhere and I'm too dumb to find it.
<We don't house a chart for this purpose here on WWM, because it can be found without much looking on the web. Here is where many answers will be found: http://www.wetwebmedia.com/pbholesftngs.htm , but I have seen and used: http://www.plumbingsupply.com/pluminfo.html and found it to be enough for me to go on, along with http://www.plumbingsupply.com/flow_charts_for_pipes.html . You may be more interested in the actual calculation though, and would find this useful: http://www.lmnoeng.com/ and one more at http://www.efunda.com/formulae/fluids/calc_pipe_friction.cfm though I think you'll find both of these to be a little more than necessary for your needs. Still, it doesn't hurt to have as close as possible to an accurate number for your system so as to provide for intentional over-engineering.>
Now on to my question.
    I have a 75g. tank with a 20g.sump. The tank came with a 1 3/4" hole in the back for a 1" bulkhead. My return pump is an Iwaki md55rlt with about 1100gph+/-. Now you are saying to yourself that's not going to work and you're right, it didn't work. so <So> I take  <took> the tank down to the LFS and have <had> the tank drilled for an additional 1 1/2" bulk head. Now here is the funny part, have you guys ever heard of doing this? the LFS suggested instead of a 1" bulk head in the 1 3/4" hole  to use a sch40 1 1/4" male adapter with the bulkhead gasket inside the tank to a 1 1/4  female adapter outside with the threads siliconed. should <Should> work right?. this would give me  1 1/2 " and 1 1/4" overflows, and both would run through separate 1 1/2 pvc to the sump. <<This can be made to work... I would use two gaskets, one on the inside, one on the outside... and apply a liberal amount of Silastic to both/all... and synch the threads up... hand-tight. RMF>>
<Are these fittings inside and overflow chamber? Are they just plumbed through the glass and allowed free-flow?>
This will be a FOWLR tank with poss. some corals in the future. Will this work? Will this drain quietly? is <Is> the 1 1/4 pipe idea a bad one? the <The> way it will be piped exactly is a 1 1/2 st 90 into a 1 1/2 / 1 1/4 male adapter which has a flange on the threaded side as wide as the gasket. this goes through the tank wall to a 1 1/4 th. / 1 1/2 bushing into a 1 1/2 tee down to the sump and vented on top of the tee. I hope this isn't too confusing.
<Can't picture this setup. First you mention the separate lines from each fitting, then you mentioned a "tee" to the sump. Does this mean each line has a tee with open air to quiet the siphon, or that each fitting tees and has two lines down? In either case, this depends greatly on how it is implemented; i.e.., behind a rampart in an overflow chamber or directly in the display-body. I would not be concerned of a lack of flow, but as to the noise, I can only speculate that your tees would quiet the whole thing down.>
   please tell me your thoughts on all this stuff. thank you much , John P
<If the calculation links don't give you what you need, and the WWM reading isn't enough for you (Fat chance) then I welcome some follow-up q's, John. Good luck!
-GrahamT>

Re: Plumbing/circulation, will this work? (diameter) pt.2 2/18/07
Graham T,
<'Allo again, John.>
   Thank you for responding to my questions.
<Absolutely welcome.>
There is no overflow box or rampart to speak of. Picture a 1 1/2" bulkhead on the top right side of the tank about 4" below the top. Going into the bulkhead is a 1 1/2 st. elbow, open end facing upwards acting as an overflow and setting the water level in the tank. Outside the tank is a tee on the vertical, top acting as a vent reduced to 1" going slightly above the tank. The bottom of the tee is 1 1/2" pvc piped down to the sump. Top left of the tank picture the same setup as the right with 1 1/2" elbow (setting tank level, same height as right side) reduced to a 1 1/4 male adapter fitted through the wall of the tank back (gasketed, siliconed) into a separate 1 1/2" tee on the vertical, vented on the top with 1" etc.. etc.. . Each overflow has its own 1 1/2  piping down into the sump.
<Ok, was not sure with the last email, thanks for the clarification. Good clear description.>
So basically I have a 1 1/2" overflow and a 1 1/4" overflow to drain 1100 GPH. Is this adequate to drain this volume quietly?
<I think that the tee's will help immensely. You will still have some slurping/gurgling, what with the elbow being at the surface of the water like that. I service a few accounts in the field that use a similar setup, but where noise is not an issue; i.e.., restaurants, nursing homes, etc. Not the quietest setup, but - again - the tee's really do a lot to quiet everything down.>
I am asking you this because I can't fill the tank right now (that would be too easy to check). I had the tank drilled last weekend and didn't have anyone to help bring it back into the house. Well it was about -5* outside and I thought it's just glass, silicone, and plastic - what could happen?
<Exactly! What could happen...?>
Well the plastic trim on the top and bottom cracked in about 5 places.
<Could *THAT* happen? It could. Dang. [Sniff]>
I ordered new trim pieces from AGA but hat will take 2 weeks, bummer. I'm just trying to get everything right the first time and get good advice from the right people who know.  
<Gotcha.>
Also what are your thoughts on a return manifold for the top of the tank?  
<You mean style, location or fittings? I love loc-line all the way! I suppose with the drilling being done and all, you probably have only one option: over the lip. I'd utilize 1" I.D. for the return double-elbowed over the lip with the obligatory hole at or above the water-line to mitigate power-outage-related flooding. I suppose if you have a sufficiently rated pump, you could run a return manifold at the lip with multiple nozzles... but, it is a bit of work, and you need to have a good pump... not to mention it helps to have the basic "over the lip" setup first to gauge flow-rates, et all. I wish you luck, John. Plumbing is fun for me, as I like building the system almost as much as running it!
-GrahamT>
Thank you so much for your time and your advice,  john P
<Welcome.>

Overflow Drain Placement - 03/27/06
Hey guys, good afternoon/evening/morning.
<<Gals here too...Good Morning>>
One more question about my sump setup.  I've got two returns (on each side) and two (soon to be three) drains plumbed very near the top (center) of my tank, utilizing strainers attached directly to the bulkheads, and no overflow box.
<<Mmm, much like mine...>>
My problem is because of the location of the drains (about 1" from the top), one of them creates an almost constant and irritably loud "sucking" noise as air funnels into it.
<<Yes...know what you mean.>>
Ironically enough, this process seems to be the one thing allowing my drains to keep up with my oversized pump because the water flow through the drain seems to be much greater when this is happening.  I am going to add a third drain, hoping that this will alleviate the need for the other drain(s) to suck in air, and still keep up with the water flow desired.
<<It can't hurt to add the extra drain, but I would like to suggest you replace the bulkhead strainers with PVC 'elbows' (you may need to cut/shorten/modify these to suit).  These can be positioned (angled) to pull water from the surface...this will allow some air to enter and let you "adjust" the water height in the tank, as well as "skimming" the surface film from the water.>>
My pump is teed off with a valve, so I can adjust the flow (right now the valve is fully open).  Is the water level in the main tank always going to level off at the point of intake?
<<Usually, though "overdriving" the drains can keep it elevated slightly as you seem to be doing...a dangerous balancing act.  Best to employ something similar to what I have suggested.>>
I am aware that it possibly was foolish to plumb my tank like this because of the weak water flow through the drains (due to lack of pressure at the top?), I just got the impression in my research that it was alright.
<<Is "alright" in my opinion.  Much better than "bottom" drains in the event a bulkhead begins to leak...won't drain the whole tank.  If these are 1" drains, it's my opinion that it is unrealistic to try to push more than 300-350 gph per drain...no matter where they are located.>>
Have you heard of any tanks plumbed like this (with the drains at the top of the tank, and no overflow box)?
<<Yep...mine!>>
On a side note, my AquaC Remora stopped producing skimmate when I placed it in the sump - any common reasons for this?
<<Yes...the fact you are pulling water from below the surface (bulkhead strainers) in the tank, coupled with the water turbulence in the sump, reduces the "concentration" of material the skimmer picks up, thus reducing skimmate.  Placing the skimmer in a skimmer "chamber" within the sump that receives raw surface water from the tank can help with this.>>
The intake for the skimmer is very near the top of the sump water level, and there is a lot of water movement in the sump.  Thanks again guys for all your help.  Regards, Chris Stevens
<<Cheers, EricR>>

Overflow Drain Placement II - 03/27/06
Eric - thanks for the reply.
<<Quite welcome Chris>>
Glad to hear someone else runs their tank in a similar fashion.
<<Yep...Probably more prevalent than you realize.>>
Do you know a good source for BLACK PVC elbows (1" and 3/4", at least one end male) - ordered one from marine depot, but it's white.
<<Mmm, nope...haven't ever found black PVC fittings, though I hear they exist.  I've used black ABS fittings before, but I don't think you can get anything smaller than 1.5" (can be bushed down)...but then I always buy local (HD, Lowe's), you might find something smaller on the internet.  Likely your best option will be the gray schedule-80 PVC fittings.  You should be able to find these locally at a home center/hardware/plumbing store...and at a better price than from a fish shop etailer.  The fitting you describe with the one male end is called a ‘90-degree street ell’.>>
Thanks again.
<<Regards, EricR>>

Equipment/Overflows/Operation    4/12/06
Thanks for all the help you folks provide. <You're welcome.> I'd probably drop this hobby if I didn't have your site to research. I am setting up a 140G tank and had a few
questions.
1)  My tank is acrylic with two cut-outs. The internal overflow box is very noisy since I have a 30" high tank. (I know it wasn't a smart move but
I purchased it for the volume before reading your site and discovering it's quite a bit more work to maintain.) Anyway, I don't want to put in a Durso
tube but I was wondering if there was any problem with putting a 15-20" PVC tube onto the overflow so that the water level in the overflow is raised and
the subsequent drop is less noisy. Do I have a higher chance of clogging with the tube than without?  <Geez, most come with a standpipe.  I would cut
slits near the top of the PVC, will reduce noise some.>
2)  Would I adversely affect my tank by using a piece of Plexiglas to cover my overflow box? <No.> All the noise generated by my setup is from the drop
in the overflow box. I have a Megaflow 4 sump and it is pretty quiet.
3)  When curing live rock, would it help using a poly filter and/or carbon?  <Yes, but a protein skimmer would serve much better.>
Thanks again for all the help.  <You're welcome.  James (Salty Dog)>
Mike

Sump/Refugium (Overflow?) Confusion - 04/08/06
Hey folks me again.
<<Hello "me">>
I have a Perfecto 125 gal reef ready with two corner flows.  I called the company and they said each overflow is rated at 700gph.
<<Mmm, yes..."rated" indeed...but expect only about half that before incurring problems (excessive noise, surge, air entrainment issues, etc.).>>
This gives me about 1400gph to use.
<<A lot of water to try to push through a sump...hope it's not in your living room.>>
I would like to use a Mag 18 for my return and according to spec it will give me a little less than 1400gph with the head length.
<<As I've intimated, I think this will be too much flow for your overflows/sump.  Go ahead and give it a try...just be prepared to make adjustments/downsize the pump if things don't turn out as you expect.>>
I will use a "T" and a gate valve on the return.
<<wise>>
My question is this.  First question I have is can I run a "T" off one of the drains, put a gate vale on it and let it drain into a refuge chamber in a sump.
<<You can>>
The water would then flow over a baffle to the second chamber.  This is where I will be doing the skimming.
<<I would design the sump/refugium to skim water 'before' the 'fuge to keep from trapping/removing beneficial plankton/epiphytic matter on its way to your fish's/coral's mouths.>>
Then I will pump the water back into the display with the Mag18.  If this sounds ok what size should I have for the refuge.
<<As large as physically possible.>>
I want the main purpose for nitrate reduction.  If macroalgae is suggested then what type could I use and feed the extra to the fish.
<<My personal fave is Chaetomorpha (is what I use), it provides an excellent, dense matrix for pod/plankton production.  But if your looking to feed your fish with the algae, Gracilaria is probably a better choice.  Though excellent nutrient export mechanisms, I tend to keep away from Caulerpa species due to their inherent risks (toxicity, sexual events, et al).>>
Would it be a problem with the raw water going directly into the refuge portion?
<<Nope.  I have separate vessels for my sump and refugium...the 'fuge receives raw water from the display which then flows to the pump chamber in my sump.>>
The last and biggest question is, I have been looking all over the internet and can not find a sump/refuge that will do the above.  Any suggestions.
<<Have a look here and among the indices in blue:  http://www.wetwebmedia.com/sumpusefaq10.htm >>
I don't know if a DIY project would be appropriate with my skills.
<<Not all that difficult...really.>>
If you have other suggestions for the sump/refuge let me know as I am confused on how to do it right.  I know 'right' is a matter of opinion but I trust your opinions.
<<Indeed my friend...for a combined unit, my "opinion" is to have raw water flow in to the skimmer chamber (first chamber), then overflow to the refugium, which then overflows to the pump chamber.  Baffles to help eliminate excessive bubbles can be installed between the skimmer chamber and refugium chamber.>>
Thanks a bunch and I am still reading your site.
<<Excellent...lots of material/help abounds.>>
With all this knowledge I am starting to look like I am on steroids (hehe).
<<Heee!  EricR>>

Inlet for closed loop manifold  - 04/05/2006
Good afternoon WWM crew.
<Trevor>
I am currently in the planning stages of engineering a closed loop manifold for my 180 gallon AGA.  Through your extensive FAQ,  which is truly priceless, I believe I can successfully generate the manifold component and also appropriately "size" the pump for the desired flow rate in the display tank relative to head, horizontal run, elbows, tees nozzles.
<Yay!>
What I have not been able to clearly extract out of this wealth of information is the appropriate inlet size relative to desired flow rates in the display tank.  I have come across information on drain rates through bulkheads:   ~ 300 gph, 750 gph, 1000 gph for 1", 1.5", 2" bulkheads respectively.  Do these aforementioned numbers remain the same if one is "attempting" to aggressively pull water through the inlet with a pump or are they based on a  flow rate due to gravity's "pull" alone (my instincts tell me that if most inputs and outputs on external pumps are 1" that a 1"inlet  in the display tank should be able to handle whatever the pump is rated ... but I have been wrong before and I am sure I will be again)?  
<Can't address the last adequately (is a great question/statement), but you are correct in questioning the intake sizes as stated if there is any restriction/vacuum consideration... that is to state, these diameters are idealized for no such restriction, including intake screening>
If I have a 2" inlet in my display plumbed directly to the input of a pump of infinite flow rate what would be the maximum flow rate that  could be produce, for simplicity, at the output of the pump (I am assuming at some point the 2" inlet has to limit the pumps ability to intake water at a greater flow rate ....
<Let's stop here: about 800-1000 gph...>
or am I wrong and my flow rate is actually infinite gph)?
<Ah, no. There are practical limitations, induced drag, sp3 hybridization, Brownian effects, affinities of water to contend with>
I want to maximize the flow rate of my closed loop manifold using a 2" inlet from the display plumbed directly to an external pump, but I do not know what I can expect to maximally pull through the 2" intake.
<The above values are about it in practical terms... one can (of course) pull/push more through a two inch diameter line, but there are other considerations, principally screening issues, that need to be addressed>
Thank you in advance for the sharing of your knowledge and experience, again, it is truly appreciated.  Trevor
<Is this clear? You want to avoid "sucking up livestock", cavitation, drawing in air... Bob Fenner>

One pump or two?   5/15/06
Hi Crew
< Hello Adlai! >
I am trying to plumb my new 120 gallon and wanted some advice before going down this path.  Taking your advice I swore that my next tank would be reef ready - no more dinking saltwater for me via J tubes.
< I cant say I blame you a bit! >
The tank has 2 overflows rated at 600 gph each so I expect 1200 gph approx into my sump. In ADDITION to sending water through the 2 returns which come with tank setup I also plan to draw water from the sump via a SCWD using a ViaAqua 2600 rated at 740 gph. This means I will have 4 returns (2 with the overflows and 2 with the SCWD) using the sump water.
So I figured I needed approx a 1200 gph submersible to make allowances for head loss pressure etc. Since the drains are only rated at 1200 gph that is the maximum amount of water that will be coming in to the sump which is 12X24X14. The 2 returns can be powered by either 1 pump (any recommendations) or 2 separate pumps ( I have an Eheim 1260 and a ViaAqua 2600). In addition, another ViaAqua 2600 which is also in my sump, will be shooting water through a SCWD and 2 separate returns.
In regards to the SCWD return, my thinking is that since the ViaAqua is rated at 740 gph, I expect about 50% of water flow because of the SCWD and the returns i.e. approx 370-400 gph of flow.
< You are correct, the SCWD reduce the gph significantly. You may want to employ a larger pump to enjoy the benefits of the SCWD. 400-500 gph will be almost unnoticeable. Think about running the SCWD on a closed loop, with a pump rated for 1000-1200 gph. This can be done without drilling any more holes in the tank. When plumbing the SCWD, consider installing true union ball valves. This will allow you to shut off the water completely, and service the SCWD without losing too much water. Some people will have a secondary SCWD to switch out, while cleaning the first. >
In regards to the regular returns , the Eheim I currently have is rated at 635 gph will give me about  50% water flow at a 5 foot head approx 320-400 gph. The other ViaAqua 2600 will give me about 350 gph at 5 ft head So when I add all 3 pumps in the sump I will be getting approx the 1200 gph which the returns are rated at.  Are there any flaws to this logic?
< Three pumps in the sump may generate too much heat! >
Am I not considering any potential challenges. Should I just use 1 submersible pump to send water back the 2 tank returns so that I will only have 2 pumps in the sump.
< Think about running one pump for the return, rated at or near 800- 1000 gph. With the build-up of detritus and biological waste over time, the maximum water handling of the overflows will be reduced. It is better to be slightly underpowered in that regard. Also, if contact time is crucial in the effectiveness of the filtration methods employed in the sump, slower is better. Think of it this way... Let's say your job is to steal hubcaps. Would you be more successful on the freeway, or in a parking lot? >
I hope this makes sense.
< Makes sense to me! It is good to see planning and consideration! >
Thanks in advance
< You are very welcome. RichardB >

Re: New 90 Gallon Setup... closed loop issues   6/13/06
Hello Bob,
   <Scott>
  Thanks for your reply.
   <Welcome>
  Based on the expert advice I have been getting (including yours), I decided to increase the size of my new system to 135 gallon. This will afford enough space for external pumps, and hopefully provide more options for (healthy and happy) fish stocking.
   <Great>
  Also, I believe this size should provide adequate space for my Centropyge aurantius (currently in quarantine and eating habits continuing to improve). Would you concur or should I consider finding another home for this beauty?  
   <In the wild this is one of the Centropyge species with a large "territory"... like many cichlids, it can be crowded a bit...>
  In discussing the new tank configuration with a LFS, they suggested an enhancement which I would be very appreciative to hear your thoughts about (I did not find it addressed in the Circulation FAQ's in WWM and apologize if it has been addressed before). Anyway, here goes - The current setup would use 2 overflows to feed an Ecosystem 3612 (roughly 1200 GPH per the manufacturer) and back to the display. The balance circulation (say another 1200 gph) would be provided by powerheads. My LFS representative suggests doing away with the powerheads and plumbing a separate loop taking water from the back of the tank (about half way up the tank) behind the overflow boxes (the boxes would be equipped with Durso standpipes so that a water column would remain in them). The lines would be joined together to feed a parallel external pump and back to the display via 2-3 additional bulkheads located at the lower portion of the tank.
   <Sounds like a plan>
  I like the idea because it eliminates the "issues" with powerheads such as heat generation, exposed intakes, etc., but am wondering if we are drilling too many holes in the back of the tank. Would you have any thoughts to share on this?
   <More holes can lead to more potential problems... if it were me/mine, I would not cut these through-puts quite so low... "just in case"... But near/closer toward the upper surface... not too close though, to prevent loss of water during change-outs>
  Thanks again for your help on this project.   
  Scott
<Glad to share. Bob Fenner>
 

DIY...Internal Overflow Question    8/13/06 Hello! I have a quick question that I can't find the answer to anywhere else. I'm in the middle of designing/arranging my new [and first!] set-up.  It will be a 125 gallon salt water tank-- reef with some fish. I am mainly working on the sump/overflow.  I am using a few 10 gallon tanks as a sump underneath the display. <Much better using one sump.> I want to use an internal overflow system to get water to the sump.  Here's the question:  Can I NOT include the internal walls (i.e. just have the two pipes sticking up in the water)?  A very basic drawing is attached.  In this layout there are two drains (1.5") and two returns (1").  I'm probably going to try to pump/drain about 1000 gph through the display.  What are the issues with no corner box section?  The pressure on the bulkheads?  Fish getting through?  A lessened ability to pre-filter the water?  Accidentally draining 125 gallons if there is a leak?  Is this idea something I can even consider? <Would not consider doing this.  Should one of the bottom bulkheads develop a leak (while you are at work, of course) you will come home to a flood as the entire tank could drain.  Is best with a sealed internal overflow, or overflow returns near the top of the tank exiting out through the back wall.  If a leak develops with this set-up, you will still have an angry wife, but on a scale of 4 rather than 10.  I have seen your design employed often, but is very risky. > Thanks so much, <You're welcome.  James (Salty Dog)> Chris

Using Old Rock/Drilling Bulkheads - 08/27/06
Hey guys,
<<Hello (but don't forget the very capable ladies here as well)>>
Thanks again for your time and dedication to our hobby!
<<Is an honor/pleasure to help>>  
I have 2 issues I need help with:
<<Alrighty>>
First, I have read thru the LR section in depth and could not find an exact match to my problem.  I recently purchased a used, and neglected 120 gallon that housed a single clown grouper with several large pieces of rock (it was a FO with rock??).
<<Indeed...that would be a FOWLR (Fish Only With Live Rock)>>
I have kept the rock wet for a few days and can see a few small life forms on it (actual moving little white/clear bug things).
<<Amphipods...probably>>
The rock looks terrible as the tank was neglected and the rock is all dark brown and black.  I will be setting this tank up as a FOWLR and I am thinking that I would like to start over with the rock.  Letting it dry and cleaning it somehow and then letting it cure in the tank for a month or two before adding new fish (pending testing results).
<<Mmm...letting the rock "dry out" will negate its benefits...why not simply keep the rock as it is?  If the color is an issue, it will likely change with improved water quality/lighting>>
Can I get the rock to look better?
<<Depends on what you consider is "better">>
Is it worth losing whatever life it has on it?
<<Not in my opinion>>
It was not really a traditional live rock,
<<...???>>
it has life but it looks very bad.  They are great sized pieces.  The substrate is crushed coral, I would like to reuse it.  It also has black and brown staining on it.
<<This is most likely forms of algae, and will "change" with changes to the environment, as stated>>
Can this also be cleaned?  If so how?
<<Swirling/rinsing with clean saltwater will do the least damage, though you will still loose some biota>>
I don't mind starting over on the rock but will my cleaning methods effect any future fish or possible changes to inverts/coral down the road if I go that direction?
<<Indeed it will...you could give the rock a rinse and a "light" brushing with a soft-bristle brush, or replace it (entirely or in portions) with fresh live rock>>
Second, the tank is a traditional (non RR) tank.  It came with a sump/wet-dry and a HOT overflow.  I am weary of the overflow as I hear that they will eventually fail.
<<Is a good chance, yes...but this risk can be lessened a great deal by employing a redundant system (two siphon overflow boxes) with the first>>
I have once again read on WWM about tank drilling and am thoroughly confused by all the different opinions and issues.
<<Let's see if I can help un-confuse you>>
I would like to drill the rear for 2 sump supplies and 2 sump returns.  Where exactly (how far down and over/apart) do you recommend?
<<Well, if you've established the back glass in non-tempered, I recommend you place the throughputs the width of the hole-to-be-drilled from the edges of the tank, and no closer re to any other throughputs...clear as mud?  For example...a heavy duty 1.5" bulkhead requires a 2.6" hole...the edge of the hole should be no closer than 2.6" from any edge of the tank, or from any edge of another bulkhead hole.  Adjustment of water height in the tank can be accomplished with elbows to raise the level of the pipe outside the tank, or used as adjustable "overflows" within the tank>>
Also what size is best for this size tank if I use a strainer for the supplies down and a directional elbow for the return up?
<<Two 1.5" bulkheads for the drains, and one or two .75" or 1" bulkheads for the returns...or you can simply plumb the returns over the back/ends of the tank>>
Should both the supply and the return have a T installed before the sump?
<<For what purpose?...in what configuration?>>
Also, are there and tips for drilling?
<<Indeed, yes...have a read here:  http://www.wetwebmedia.com/pbholesfaqs.htm >>
I have seen a tank drilled before and they used cooking oil for the lubricant while cutting?  Is this OK?
<<I've always just used water for lubricating the drill bit...works well and is easy to clean up>>
I plan on ordering the needed bits online, any recommended sources?
<<Several choices about...I bought my last bit here: http://www.diamond-drill-bit-and-tool.com/Diamond-Drill/MAIN.htm >>
Any tips?  
<<Heat is your enemy...follow the recommended rotation speed for the size core drill bit used.  The manufacturer states these bits can be used "dry", but use of a lubricant (water) will keep heat down, greatly extend the life of the bit, and speed the drilling process...I use simple 'Play-Dough' to create a "damn" around the area to be drilled and fill/refill with water as needed while drilling.  Also, when possible, use of a drill-press or drill-jig to keep the bit vertical to the glass surface will lessen the chance of damage/fracture of the panel>>
Thanks once again for your help and contribution to our obsession!!!
Randy
<<Quite welcome.  Regards, EricR>>

Tank perimeter trim and back wall over flow vents   8/30/06
Hey crew!
<Jean-T>
I made a sump out of an old 55 gal tank. I added silicone over the existing silicone
<Not a good practice... doesn't adhere well. Should be cut out, replaced...>
just to be safe. (I know this is somewhat useless since its the film between the glass that does the job..
<Oh! Yes>
but I feel better still)
I noticed that the plastic perimeter trim on the top and bottom of the tank was cracked in all corners.
<Mmm, this is more for assembly, looks than structural...>
I am having a hard time finding replacements at local pet shops and have no  credit cards to order them via internet.
<Make a deal with someone who does... send them a check in advance...>
Do I really need this trim ?
<Mmm, very likely not>
I have 4 baffles in the sump so this may compensate as reinforcement??
<To some extent yes... I wouldn't worry re... you probably won't have this filled very high...>
   Also I have 4 drains across the top of my back wall (1 inch bulk head)  and my pump will be pushing 1200 gph.
Do I need to pipe  vents into the overflows so they can draw air?
<Mmm, likely a very good idea to have "tees" at the down junctions... may well have to aspirate these to cut the "gurgling" noise... See WWM...>
  I once herd that if no vent is present it can greatly lessen flow? is his true?
<Mmm, in some cases these small diameter lines can/do operate as siphons... but this is not a good idea all the way around... if the size, number of drains is insufficient and one or more should become occluded...>
Do you think my drains will handle 1200 gph?
<No... all this is gone over and over...>
my return to the tank is via  4   3/4 inch  returns ? does this sound right for 1200 gph in a 90 gal tank?
<Depends on the pumping mechanism, but no... not real 1,200 gallons per hour>
tanks so ever very much for your precious time! thanks!!!!!!!!!!
  Tristan!!!
<Please read here: http://wetwebmedia.com/marsetupindex2.htm
Scroll down to the areas on plumbing, overflows, bulkheads, noise... and read... Better to re-drill, fit large-enough through-puts now. Bob Fenner>

Check valves and Overflow - 10/15/06
Hi there,
<Hi.>
I found your site after doing an exhaustive search for alternatives to Check-valves.  I have a 250 gallon tank with a classic wet-dry sump design with overflow boxes on each corner.  The problem is my return lines.   I have two ½" returns on the very bottom of the tank so there are no stand pipes to break the siphon. <You should consider building some. This is a very weak point in your setup. Try to visualize 250g of water on your floor.> Additionally, I have a ½" return that has a standpipe that runs up the left overflow box and then goes back down to 2 bulkheads that return the water to the tank, this one has a small tube that is supposed to break the siphon.  The same thing exists on the right side except it does not go back down to the bulk-heads through the return box its just a single ½" pipe that has t connectors to the two bulkheads and just ends at the top so there is no anti-siphon pipe at the top.  My question is:  Is there an alternative to completely changing the way water is returned to the tank or using un-dependable swing check-valves. <If there is, I'm not sure what it would be... check valves are about as reliable as they need to be but need to be inspected/tested at regular intervals.> I guess I could do check valves but will have to clean them every month and there is still the possibility they won't work. <If you clean them at this interval, then they will work for years. I use the dual-union style so that they are easy to take out of service for maintenance.> Any thoughts would be welcomed.
Thanks,
Jason B.
<Cheers, J -- >