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Something I've been wondering about, since I'm new to the larger tanks.

I have a 55 gallon tank, and it came with a heater that's rated for "up to 50 gallons" - which of course I thought can't be enough for 55 gallons, so I got a 10-30 gallon heater to supplement it. I put the 50g heater under the filter, and the 10-30g heater at the other end of the tank to try to make sure all the water was kept properly heated. But I'm concerned, because my fish seem to keep to certain areas of the tank, and when I get up in the morning I'll find some fish, like my mollies, clustered around the smaller heater, and the tank temp (according to the stick-on thermometer) is around 74. It seems that the house temperature is actually affecting the water temp more than the heaters are.

So, questions:

1) I'm thinking the heater that came with the tank (used) probably needs to be replaced?
2) What's the best location in a 55 gallon for the heater?
3) Am I better off with a single heater rated for the larger tank, or two heaters at either end of the tank? It just seems to me that even with the filter circulating the water, that the water temp in the farther end of the tank is going to be colder than it should be.

Layout of my tank (from the top):
----------------------------
|----FFLH----------SH--|
|--------------------------|
-T--------------------------

FF: filter
LH: large heater
SH: small heater
T: thermometer

Listen! Do you smell that?

IMO, I always go with the next size up in tank heaters. This way the heater doesn't have to work as hard, I feel it saves the life of the heater. I also use the hydor in line heaters with canister filters on my larger tanks this eliminates cold spots. I would look at the heater it see if has any visible damage. Burn marks, Broken coil wire, water inside the glass housing.

I think you correct in your thinking that the fish a huddling for heat. Yes the room temperature will effect the the tank temperature, and with a swinging water temp. the fish will experience stress which can lead to health problems. There are a lot of heaters out there, with different prices, I don't know what you can afford by I use the stealth heaters and have not had any problems with them, but at some point they will wear out I'm sure.

I hope that my opinion was helpful.




Djrichie
"So Long, and Thanks For All The Fish" Douglas Adams

Two heaters rated for close to the tank size is usually best. They don't have to work as hard as indicated in djrichie's post, and another benefit is that if one suddenly dies and you don't have a back-up handy, the good heater will sustain until you can get another.

Yes, atmospheric temperatures will mess with your tank temp, but as the volume of water gets larger, this effect will be less. A 55 probably won't lose too much heat overnight if you have a tight fitting hood unless your room really gets fridgid.

In conclusion, i'd get a larger heater for your small heater and keep the original around. Your tank needs a total of about 275 watts (going by the 5w per gallon guideline) so two 150's or 2 200's on either side of the tank would be best. Two heaters heat the tank more evenly and they'll last longer this way.

Also i'd suggest you step up to a floating thermometer, as the "digital" stick on thermometers are crap. They take the temp on the outside of the glass, and are more effected by room temps than other thermometers, so you really can't judge tank temps by them.

Good luck!

Yay, I always like to hear when my thinking is correct at least in one point. (having two heaters was better than one)

And a new hood is also on the purchasing agenda, but not til next month when I get paid again. The lady I bough the tank from didn't have a full hood for it, she was using two 'value' 20/29 gallon tank covers with lights. Not even really hoods. They're just plastic pieces with windows and hinged doors that sit on top of the tank and the light fixture sits on top, held in place by plastic tabs. And one of the lights doesn't work and I can't figure out why (have swapped the bulb, the ballast, the starter, and the round silver thing whatever it's called), so I'm just going to buy a full hood.

I have the feeling Fosters & Smith is going to make a good bit of money off me next month. :/

Listen! Do you smell that?

If you get heaters with the temperatures on the dial they will read the tank temp and turn on and off as the temp goes up or down. That takes out the effect of the room on the tank temp unless the room goes beyond the temperature you want the tank. If you have a room at 76 don't set your tank temp at 74 and probably better to set it slightly higher than 76 like 77-78 to avoid large fluctuations in temperature. If you don't have heaters with the numbers on the dial they will not read the tank temp. They will only put out a set amount of heat so if the room temp changes the tank temp will change by a nearly equivalent amount. No reason not to get the slightly better heaters since they only cost a few dollars more and can make a big difference in how stable the temperature is. Doesn't matter if the room is 65F or 78F my 55g sits right at 78F throughout the whole tank and right now I only have 200w from 2 small heaters instead of the usual 300-400w. I always use 2 heaters when possible since if 1 malfunctions the other can keep the temp from dropping too much or if one gets stuck on a smaller heater is going to heat the tank up slower so you have time to catch it before fish die.

Put heaters in the highest areas of flow but as far apart as possible. With hob filters I always put 2 on a 4' tank otherwise the flow is too low on one end. Even if it's just a small filter rated for something like 10g it helps to have that 2nd filter at the far end of the tank(opposite side of the brace) from your main filter. You can also stick a powerhead on one side. It will prevent dead areas with little flow and keep the water temp even throughout the tank.

Well, I have two UGF's in the tank as well, and one of the plans is to get a powerhead and put it on the far corner stick-up-pipe-filter-thing of the UGF to get some current going on that corner of the tank, especially since that side is where the fish seem to congregate most of the time.

See, that's what's been bugging me. The fish seem to stay in what would logically be the coldest part of the tank, yet they all should crave the warmer water.

The smaller heater I have is supposed to have a thermometer set in it, to read at 78 degrees F, and turn on and off as needed to keep the water at 78 degrees.

Listen! Do you smell that?

IMO is they are hanging around the smaller one because it is working the most meaning it stays on or is on longer, and they like the heat. In tank heater heat the water as it passes by then mix with with cooler water. Mostly likely the little one is trying to keep up with the larger one at keeping the temperature balanced and uniform.

Djrichie
"So Long, and Thanks For All The Fish" Douglas Adams

Either that or they're just congregating there while they sleep because it's the area of the tank with the least water flow.