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FAQs about Marine Aquarium Heating, Control

Related Articles: Heater Impressions (Reviews) by Steven Pro, Marine System HeatingColdwater SystemsControllers

Related FAQs: Heating 1, Heating 2, Heating 3, & FAQs on: Rationale, Heating Methods/Gear, Measuring/Thermometers, Heating Troubleshooting/Repairs, Makes/Models by Manufacturer, & Chillers, & FAQs on: Fans For Cooling, Chiller Rationale/Use, Selection, DIY, Installation, Maintenance, Troubleshooting, & Water Temperature

Mmm... therms in (lighting, pumps, powerheads, UV's... heaters!), therms out... a factor for evaporation, thermal insulation...

Titanium heaters   5/2/10
Hi crew!
I need your help. I've got a 240 gallon aquarium with three heaters
<Mmm, I don't generally "trust" small "aquarium heaters" to their own controllers... I strongly suggest you look into an external controller to plug two heaters into, give up on the third, or use it in the intermediate
sump suggested below>
in my sump. These heaters are capable of maintaining its temperature, except while I'm doing a water change. I have my 1/4" tap water filtration plumbed into the discharge side of my sump, and a 1 1/2"
drain plumbed into the intake side of the same sump.
So my dilemma is that during the water change my temperature goes down.
<I'd pre-heat, heat the new water before introducing it... and have some sort of "fail safe" mechanism/s built/engineered into this water refill system. That is, I would, do not trust the one quarter inch delivery to
"stop"... I suspect it is actuated/controlled by a single "float switch" mechanism... I would use an "intermediate sump" for your make-up water... Heat, do whatever treatment you want there... and have this finite volume of water available to do your changes... re-fill it periodically>
If I do a trickle, the temp. could take 8 hours to go down, If I do full force (rapid WC), the temp. goes down in about 2 hours. We're not talking about a huge temp. drop, about 3 to 4 degrees.
<Depending on the livestock, this drop may not be a big deal>
It then takes another 12 to 16 hours to regain the original temp. So I'm restricted as to the duration of my water changes.
So my thought was to get a 800 watt Titanium heater to cure the problem. I'd be happy if I was restricted to doing a trickle change for 24 hours if the temp. stayed the same. I've heard these types of heaters heat faster
than the conventional glass tube types. Does anyone have experience with these. What brands are better? Anyone been using one for years? Best prices?
Thanks for your help.
<See Aquatic Eco-Systems site for their offerings if you go the Ti heater route. T'were it me, I'd do what I outline above instead. Far safer, less energy consuming. Bob Fenner>

One More Skimmer Question To Add To Your Site, sel.. Chaetomorpha tumbling, fan CFMs -- 03/26/10
Hey guys!
<<Hiya Drew! Sorry for the delay'¦ Work has been a bear and I'm afraid I let your query linger in my box a bit too long. But hey, as I have been reminded'¦I'm just glad to have a job [grin] >>
You've helped me out before so hopefully you can again.
<<I shall try>>
I read through your info on skimmer selection and found that really helpful, but am still in need of some guidance.
<<Mmm, indeed'¦ It can be a bit confounding/intimidating considering the considerable outlay of funds involved with the purchase of a 'quality' unit>>
I have a 180 gallon drilled tank with a MegaFlow 4 sump/wet-dry. It is going to become a well stocked reef and have a moderate bioload.
<<Do research our site re reef tanks and wet/dry filters'¦most don't advocate the use of such filters in reef systems>>
I found a Coralife skimmer 220 that was used for 3 weeks for $100 which is about half the cost of a new one
<<Mmm, did you check yourself? Marine Depot sells this skimmer new for $112.00'¦and a search on the net can get you one 'new' for as little as $105.00>>
so I picked it up just to have something on the tank.
<<And that's pretty much describes it'¦am not a fan of these skimmers>>
How well will this skimmer work when the tank is dully stocked with corals and fish?
<<I do think you will find the money would have been better put toward a better skimmer>>
Following that should I look into a better skimmer down the road?
<<Absolutely'¦ AquaC, Euro-Reef (now Reef Dynamics), H&S, Tunze, Deltec'¦and maybe even the Octopus line of skimmers>>
I know you guys are fond of the AquaC and Euro-Reefs.
<<Yup'¦the ER is my current fave>>
What style and price range am I looking at if I decide to get one of these down the road?
<<I favor the needle-wheel 'style' of skimmer, but other types offered by the manufacturers I've listed will also serve. As for price range this will be variable among the differing manufacturers. I do suggest you get the 'next size up' from what is 'suggested' where possible'¦and expect to pay $300.00 and more>>
Also I took out the bioballs in the sump/wet-dry because I heard they are a nuisance in a reef tank.
<<One way to put it'¦do research our site for a full explanation>>
Should I replace them with live rock or rubble?
<<You can, yes'¦or even use/rig the chamber for chemical filtrants (carbon/Poly-Filter)>>
The previous owner of the tank threw in a refugium that he had running with some success, but it was neglected and became a rotting mess.
The dimensions are 8"wide x 7"tall x 36"long. Because of the shape of it I can't figure out how I will ever get Chaeto to "tumble" any ideas?
<<Not to worry'¦the Chaetomorpha does not have to tumble. I have kept 'non-tumbling' Chaetomorpha in a 55g refugium for nearly seven years now. Just supply adequate lighting and flow (as little as couple hundred GPH has proven sufficient in my experience), and keep it thinned periodically, and it should be fine>>
It's hooked into the main pump using a tee section and a ball-valve, but I can't adjust the flow too much higher because of the baffle system at the entrance of the refuge that causes the sand bed to float into the water which drains back into the sump.
<<As stated'¦no need for a huge amount of flow>>
I know this won't work as a true refuge,
but my main concern was added filtration from the macro by pulling out nutrients.
<<It can/will work'¦but within the confines/limitations of its size>>
Lastly I've been looking into cooling fans for the halides in the canopy to keep them from running hot, keep evaporation under control,
<<Actually mate, 'promoting' evaporation will assist with cooling of the tank water>>
and to make sure the heat doesn't warp the wooden canopy I built. I found some great prices for a variety of fans, but don't really know what CFM I should be getting?
<<Pretty much anything that moves air will help'¦just keep in mind the higher the CFM rating the LOUDER the fan is likely to be. I utilize 12v fans for this reason (generally not as powerful as 110v fans given the same size'¦but lots quieter) but if you use 12v units you will also need a suitable transformer/s>>
I also don't really know what CFM means in layman's terms.
<<CFM stands for Cubic Feet per Minute and references the 'volume of air' the fan is rated to move>>
Could you guide me in the right direction?
<<I hope I have'¦do look to sources 'outside' the aquarium industry for the best prices>>
Sorry for the length of this, but I know you guys are busy and I hate to bother you with multiple questions.
<<No worries mate>>
So with that being said, I'll let you get back to work. Thanks for all your help and guiding words.
Sent from my iPhone
<<Is a pleasure to share, Drew'¦ Cheers'¦ EricR Sent from my HP desktop>>

Temperature Question, chilling? 9/14/09
Hey Crew,
My tank is averaging 86 degrees in the day and 83-84 at night. My tank is a JBJ nanocube 28 HQI and I do not wish to purchase or rather cannot afford to purchase a chiller at the moment since I am still a student. Now, I do
realize that there are areas in the world where natural reefs occur in this temperature range and that there are even some reefs the get into the 90's.
Being that the temperature is at 86, it shouldn't produce any adverse effects to the organisms inside, should it?
<The "90's" generally occur in shallow lagoons. One thing you must keep in mind is that organisms do their best when living under the conditions they evolved in. Not all organisms are going to do well at this temperature extreme. Hardy/tolerant species should fare well in your system. A small fan blowing over the top of your hood may help some. Would be worth trying. >
Thanks Crew.
<You're welcome. James (Salty Dog)>
-Jason Quan

Heater sensor location   9/26/06 Ahoy mateys and good afternoon! <Aye bee gar!> A really dumb question but one which I would really like to know the answer. I have searched the forum and FAQ's but no one has ever asked this dumbest of questions. Where exactly on the body of a submersible aquarium heater is the sensor that activates the heater to heat, or not to heat the tank water? <Up near the "top" where the electrical cord exits generally... though there are makes, models with this remoted> It's not the big things that confuse me but the wee-est of life mysteries. Thank you very much. Sue :) <There is likely an "indicator light" that comes on when the heating element is energized... the sensor is likely nearby this. Bob Fenner>

Temperature Controller 12/5/06 Greetings! <Hello devoted Webber.> I always research your web-site for advice before I attempt anything new with my small set-up. I read with interest the article that extolled the necessity of a temperature controller and now I am a true advocate. There are just a few technical points I would like explained to me. I have my controller set at 80 degrees F and the actual heater at 82 degrees F. I understand that this allows for a redundant heating solution for my tank. I understand that the heater is basically" on" all the time and the controller supersedes this anomaly. <Yes> I understand that this is why the controller can still modulate the heater if it ever sticks in the "on" position. <Yes> First question: Is the opposite true? Can it control the heater if the heater fails to come "on"? <No, if the heater is defective, nothing is going to make it come on.> Second question: Does the controller actually manipulate the bi-metallic strip inside the heater-closing and opening the connection -or does the bi-metallic strip stay immobile in the "on" configuration allowing the controller to perform this task via its self-contained computerized components? I know that heaters fail due to the bi-metallic strip wearing out and I need confirmation that this is prevented by the very nature of the controller. <The heater should be set about 5 degrees higher than the temperature you want to maintain.  This will insure the bi-metal strip is always closing the circuit and giving full control to the controller.  Controllers basically are just a hi-tech thermostat that maintains the temperature selected more accurately. There are heaters available designed to be used with controllers.  These types have no internal thermostat.> Thank you very much. <You're welcome.  James (Salty Dog)> A devoted "Webber"!

ZooMed 500R for Saltwater?  1/26/07 I have tons of extra ZooMed 500R thermostats left over from extra reptile projects. Am getting back into my saltwater setups after some years of wanting. Right now I have a 29 and 75g. Both setups are reef, under Halides, and have sumps. With the cold weather right now, I have purchased extra heaters for them that I would like to hook up to controllers to keep nighttime temps level- all titanium heaters with built in temp controllers (which are WAAAY of what the dial reads) and temp probes. Am wondering if the ZooMed reptile thermostat would be ok to use in a saltwater setup? My concern would be the probe being submersed in water 24/7. I do not know if controllers that are specific to aquariums use any different materials that one made for reptiles. <Mmm, these should work... But I would contact Gary Bagnall at Zoo Med (.com) just to make sure. Bob Fenner> Temperature Control Hi Bob! I have a 75 gallon tank with about 100 pounds of live rock. I am using a 48" Brite Lite power compact fixture by Custom Sea Life with two 65 watt 8800 Kelvin bulbs. I'm having trouble with the temperature. During the day, it creeps up to about 82 degrees and then at night falls to 80 degrees (when the lights are off). The heaters at this point pretty much never come on, so I think the lighting is causing the temperature to be so high. <Possible, yes... along with the diurnal changes in the space there... this range/change not too problematical... > This seems odd to me considering PC's aren't supposed to heat the water all that much. <Hmm, well, likely the tank is serving as a thermal bottle... oh, I see you address this below> Would it help to remove the glass canopy under the lights? <Yes... for sure... for other reasons too (light transmission...)... do regularly "top off" for the added evaporation...> Should I change my lighting period (to night time only)? It's currently 1pm to 1am. <Not IMO... as I state, the change isn't excessively large, temperature not too high... if concerned I would set your thermostats on the heaters to the higher mark (82 F.)... and they will come on at night and maintain the temperature around this... Need to be concerned possibly during the Summer... perhaps change light photoperiod then... or...> Finally, should I just try to maintain a stable 82 degrees? <Ah, I should read these queries all the way through ahead of starting to respond....> Sorry for all the questions. I live in Indiana, and it's been really warm the last few days. I haven't had this problem before, so I think it may be something I'll have to deal with in the summer only. <Mmm, yes...> Thanks for your help!!! Dave Hopkins <Glad to be here my friend. Bob Fenner, who was just up, palling around with a friend, Morgan Lidster, of Terre Haute... Inland Aquatics, at a hobby conference in Monterey.>

Storing Heaters - 3/28/03 I live in Florida and don't need my heaters (2 Ebo Jager 150 watt) in the summertime.  They are set on 77 degrees but never come on due to the fact that the tank stays a steady 80-81.5 degrees. <Set them to 79 to keep from too drastic of a fall (sic)> Should I leave them in there or would it be better (prolong their life) if I took them out and stored them during the summer months? <I would leave them in there unless you need more room. Good just in case the temp falls for some reason, or if it gets too hot in the tank (due to heated ambient room temp) and you decide to blow a fan over the top of the water for cooling.>  I didn't know if they were like TVs -- when you leave them sitting off for months on end they tend to not last as long. <I don't believe this to be the case. Again, up to you though. I would leave them in.> Thanks for your advice! :) <The pleasure is all mine. Paul> Elizabeth K. Birdwell

Thermostats for Fans, Chillers, Heaters Hello guys, Can anyone tell me where I can find an adjustable thermostat with a submersible temp probe that I can Connect my cooling fans to. THX, Wayne. <Sure Wayne! Surf over to one of our fine sponsors and look at the single and dual stage therms for heaters and chillers. The single stage will run either a heater or chiller and the dual stage runs both a heater and a chiller. Either will work for your application, just plug in the fan instead of the chiller. They are a bit spendy, but worth it!  Make sure you tell them we sent you! Have FUN! Craig> -Mounting fans in canopy- Dear Crew I just received my MH/PC retrofit. I also bought 2 Ice Cap fans.  My question is this: What is the best way to place them?  One at each end of the fixture? Across from each other?  What? <One on each of the long ends, one blowing in, one blowing out. Good luck with your new lights, and enjoy the new found heat! -Kevin> Marion

- Setting Dual Heater/Chiller Controller - How are you Gents... <Fine, thank you.> Thanks for reading... question is regarding my temp control. I have a pacific coast chiller 1/4 HP with its own built in digital temp control... and my 500 watt Gen x titanium heater also with its own temp control (dial) the heater also has a temp probe that is supposed to be submersed... I want to hook both of these units up to my 3 digit dual stage medusa controller... my question is since all items have their own temp control built in what do I set each one on... <Set the heater and chiller to full on, and let the medusa regulate between the two. Alternatively - and especially if you want a margin of error - set the heater just below the low point on your Medusa, and set the chiller to just above the high point of the Medusa, and this way if the Medusa fails, you won't be without heating or chilling.> and also being that the medusa has a temp probe to be submersed do I need to use the one on the heater...? <Either way, and especially if you want the heater to "work", then yes, all temperature probes should be in the water.> thanks for your time guys.... <Cheers, J -- >

Saltwater/Reef temperature 6/2/05 Management of SW reef aquarium temperature in San Diego, CA: I've been reeding WWM, best single hobby information source on the net as far as I can tell!  <Thanks!  Glad you think so.> Anyway, I'm gearing up to do a SW reef tank, taking lots of baby learning steps about the various techniques to run a healthy tank. I have three related questions.  <Kudos on your patience and looking before you leap!> What should I expect the natural temperature swings of an otherwise unregulated tank to be in San Diego?  <This is hard to say, since it depends heavily on your lighting, the temperature that you keep your home, the number of submersible pumps, air movement, etc., as well as how you manage your proposed outdoor sump.> How do these compare to allowable ranges for SW reef tanks, generally.  <IMO, 80-82 is the ideal range, perhaps a bit lower for fish only and a bit higher for reefs.  Avoiding large sudden swings is the most important goal.> Finally, the placement of my aquarium would allow me to build an outdoor sump through a nearby wall, holding approximately 200 gallons.  The appeal is size as well as a convenient way to pop a lid and harvest and dispose of Chaetomorpha.  How concerned should I be that this might turn into a heat exchanger for my aquarium?  Joe Kraska  <An outdoor sump will definitely affect your temperature control strategy, but could be used to your advantage.  In the winter, the sump could be kept covered and well insulated to retain heat and in the summer the insulation and cover could be removed to improve heat dissipation.  Best Regards.  AdamC.>

- SW/Reef Temperature, Follow-up - Well, I'm realizing this is a difficult subject to have an opinion on. I guess I was hoping to get a hint about what kind of cooling or heating I might need in San Diego, given the hottest few days in Summer, or the coldest few days in Winter. This part of my house is fairly well insulated, and doesn't swing in temperature as much as it might, because one whole wall is entirely retaining wall against soil, and two other walls are the same at half height. But thinking about this, and when one is running a reef tank, I'd guess that at 5-6 watts per gallon, maybe simply shutting down the fans an the halides might heat the tank sufficiently on those "chilly" outdoor 55 degree days. And if it gets too hot, extra fans can kick on, and perhaps partial lighting shutdown in an emergency? I'm planning on a programmed controller of some kind. Anyway it sufficient to "wing it", at least at first, on temperature control, using fans alone, in this climate, in a well insulated home do you suppose? <Have lived in San Diego, and know first hand that you'll need both a properly sized heater for the tank as well as at the very least fans. If you run high intensity lighting - for instance metal halide - you will almost certainly require a chiller. Most San Diego reefers that I know will not run without a chiller when most homes don't have central air conditioning. Fans often are not quite enough alone to get past the high temperatures of summer.> Joe San Diego, CA <Cheers, J -- >

How much can they take? Temperature question. >Hi, Hope all is going well there for you. I have a couple of questions for you. First of all, I live in south Florida and the temperature of my tank during the summer is usually 80 during the hottest part of the day (even with heaters off). Early in the morning when I wake up to go to work the temp usually drops to 78. Is this too much of a temperature change in about a 12 hour period?  >>It's pushing it, but no, it's not terribly bad. >Should I set my heaters to 80 so that the temp won't drop during the morning hours?  >>How about this? I'll meet you in the middle at 79. >Also, my tank is a 75 gallon F/O with 2 false perculas, 1 flame hawkfish, 1 royal Gramma and 1 coral beauty angel. I am thinking of adding a yellow tang in the next few days. I know he will probably be the most aggressive fish in the tank. Do you think there is anything to worry about as far as fights?  >>No, I honestly don't think so with that mix. If you can make sure it's a smaller juvenile then you should be golden. >Thanks for your help, James >>Quite welcome, James. Marina 

Temperature Crisis Hi, You have been very helpful in the past and I would appreciate some help again with bringing down the temperature in my tank. I have a 75 gallon Tenecor "simplicity" plus. It started off simple, then I added a protein skimmer, UV sterilizer (both in a very overcrowded sump area) and a Seio pump in the main part of the tank to increase circulation. I also removed the bio-balls and added live rock and filled that area.  I believe that as result of these add-ons/modifications have increased temperature in the tank. It's now hovering at around 86 degrees. I thought maybe something was wrong with the heater sensor so I unplugged the heater 5 days ago and no improvement.  Any suggestions on how to bring down the temperature? I really don't want to have to buy a chiller.  I've been thinking about putting the UV light on a timer and running it only 8 hours a day. I'm not sure how much that would reduce the benefits of the UV or how much that would bring down the temperature.  Also, would this temperature have hurt my live rock or any other living critters that I can't see?  <UV's aren't much different than heaters. If you have a 16 watt UV for example, then you have a 16 watt heater also. Eighty Six degrees is not a good temp for any marine animals that we keep. I'm thinking your lighting is also contributing to the high temp. If not already using, you definitely need a cooling fan in your hood also. As far as UV benefits, I personally do not like them. They kill what we are trying to produce in our live rock, such as pods etc. Whatever goes through them, good or bad is zapped. James (Salty Dog)>

Hammer coral question Hello WWM Crew, I am very new to this hobby and have learned so much from you! (I need to apologize upfront for my run-on paragraphs - my kids spilled on my laptop and the Return key does not work-he..he..). <Yikes... do either take it apart or have someone show you how to do this... can be cleaned, dried...> I have a 75 gal reef tank that just cycled. I bought 7 Turbos, 5 hermits, and 2 scarlet cleaner shrimp from my LFS about a week ago (after cycle) for a green algae problem. All my water parameters are fine (78 degrees; pH 8.2; 0 on Ammo., NO2, NO3; Alk-Normal; Calcium-460) so my LFS said I could add a Hammer Coral and pair of Percula at the same time. Everything was fine until yesterday. I added a 3rd Powerhead (CAP 800) the day before, and while positioning it, it blew some sugar fine sand all over-including a little on the Hammer. It seemed fine, but yesterday half of it retracted into its base and now all of it is retracted. Was it the sand? <Very likely yes> I am wondering if the current is bothering it now? <Not if it is not too brisk, direct> I adjusted the temp cooler for the algae problem and now the temp of the tank fluctuates from 77-82 when the two   250watt 14KMH lights are on - Is that a problem? <Mmm, yes... five degrees is a bit much... three is acceptable diurnally... you'd do well to look into fans for cooling the tank while the lights are on. To say this in another way, the daily temperature shift is likely adding too much stress> The Hammer is sitting on the sand for now, so I was wondering if I should pick it up and gently shake it to get the sand out, leave it alone, or what?  <Leave it alone... Has mechanisms for "dusting itself off"> Also, I plan to get a jawfish and watchman goby eventually, so I'd like to move the Hammer from the sand to a ledge. How high should I put it and how much current? Thank you in advance for your advice! -Stellaboom <Wait a good month before touching the Euphyllia, can be positioned about midway in depth here. Medium to low water current. Bob Fenner>

Re: Hammer coral question and "The Pepsi Syndrome", temperature variation Thank you Bob for your input! I just purchased your book and am looking forward to reading it and learning more (especially on Refugiums - I set one up based on WWM's and LFS's advice, but still am a little in the dark about it (me.... the refugium light is on 24/7 <g>). The Hammer coral has half of it's polyps out today (better than yesterday).  <Ah, good> I do have 2 4" fans with heat sensors mounted on the back of my hood, and they run non-stop when the lights are on. <Mmm> I was thinking about adding another fan over the sump (30gal sump/refugium) inside the stand. <Good idea... if not... perhaps changing, shifting your light cycle to later on in the day, more off when the room is warmer... will bring the temp. shift down a couple of degrees> I didn't have the large temp fluctuation when I had it set at 80 deg.  Should I try the sump fan first or would I be better to just leave it set higher?  <It would if this was the only practical means of reducing the variance> If so, any other suggestions for the hair algae? (which is still out of control) more Turbos? Lawnmower Blenny? Wait it out?  <Actually, perhaps "all of the above"... and more. Do take the long read on WetWebMedia.com re algae control> Thanks again! PS. Laptop will be going into the shop for a cleaning and overhaul soon-that's what I get for letting my 5 yr old twins play Spongebob on it (I was only trying to "enhance their appreciation of the living world" and the love of all sea creatures-hee :) <Heeee! I had friends spill a Seven-Up on mine on a live-aboard on the Red Sea once! What a sticky mess... but luckily the camera rinse tank was stocked with... Bottled water! So, rinsed the keys over and over... dried them, re-installed... and luckily no problems. Bob Fenner>

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