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I've got a 38 gallon tank and I bought a 100 watt heater with it at the LFS where I got the tank. The owner said it was ok, I didn't really think it was big enough, but I figured he knew what he was talking about since he's had the store for a long time. Anyways, I'm still having my doubts that the heater is big enough. The heater is a 100 watt Neptune by marineland. I'm even wondering if this is the submersible type because it doesn't look like the other ones that I have. So I guess my questions are, do I need a bigger heater? if I need a heater what size should I get? should I just get another heater to compliment this one? I tried to find my heater on the marineland website but the only ones they have there are the dual-temps which aren't either type that I have...weird. I was kinda thinking I should just buy a couple of 100 or 150 watt visi-therm stealths. They looked really cheap on big als, a lot cheaper than you'll find them in stores and they seem really popular around here.

The general rule is 5 watts per gallon.

Check the water temp in different parts of the tank. If it's lower in certain areas (most likely furthest from the heater) it might be a good idea to either replace it with a higher-watt heater or supplement with a second heater.

BigAl's has great prices, even with shipping costs. Visi-therms are my personal favorite heaters

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There is water at the bottom of the ocean

If it was me I would go with a 200watts heater at the very least, even better would be 300 watts, it won't have to work as hard and increasing the life.

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

totally agree with djrichie. in my 150g, i have two 300 watt heaters. and of course, IMO, fully submersible heaters are alot better. one major advantage that i enjoy, is to put them under the output of your filter to help circulate the heat. and again, not make the heater work harder.

Fish tanks are an expensive addiction

Maybe you can have two 100W heaters, instead of a big one.



http://www.flickr.com/photos/corydoras/
Member of the Malta Aquarist Society - 1970.
http://www.maltaaquarist.com

Randy,

The guy at the LFS was right, if the temperature difference between the room and the aquarium is 9F or less. See the attached guide from FreshAquarium.about.com.

A couple of responses indicated that you need more heating power in your aquarium. Richie suggested 200w enough for an interpolated 22F difference between room temperature and water temperature.

In any case, I like having more than one of anything in my tanks. I like two filters, just in case one quits. In the case of heaters, I like two undersized heaters just in case one quits. Jason got it right.

Unlike filters that shut down when they quit, heaters can fail in either the "ON" or the "OFF" position. Having too much wattage in a single unit may boil your fish if a unit fails in the "ON" position.

Like Theresa, my personal choice is the Marineland VisiTherm. Depending on your temperature differential, I would consider two 50 watt units or two 75 watt units.





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__________
"To steal ideas from one person is plagiarism; to steal from many is research."
researched from Steven Wright

and also what that chart doesnt say and alot of people never consider, is that as i pointed it, its all on heater location to.

as i stated, i have the 2 300s in my 150g and they keep the tank stable and do not run alot, as i have them right on the out put of my filters.

Fish tanks are an expensive addiction

Hi,
I have always placed my heaters in the flow from my filter
return as the water from the filter is "cooler" than that
of the tank. By doing that it mixes the water near
perfectly.

Normally the rule of thumb is to use 5 watts/gallon of tank
capacity. What the chart is doing is refining that rule
to increase or decrease the wattage/gallon based upon the
temperature difference between the tank and the ambient
temperature of the room. If the room is cooler than the
tank, then the flow of heat is from the tank to the room
and the heater is, in effect, trying to heat the room too!
In that case you would need a higher wattage to make up for
the constant drain of heat into the room. How much larger
depends upon the temperature difference.

Frank

-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

frank, i think maybe it was you whom i got that idea from and since then, i have all my tanks like this

Fish tanks are an expensive addiction

Well I can't really put the heater in the out flow of my filter because I've got a HOB. Unless I put the heater on the front glass that is. So it looks like my options are 2 x 100 watt heaters or one 200 watt heater.

Rnady,

If the heaters are submersible, place both perpendicular to the substrate. One should be beneath the outflow from the HOB. I have AquaClears on each end of a 125G. The flow from the right unit sets a current down and to the left. The unit on the left sets a current down and to the right. The collection zone for "stuff" is the center of the tank. Water flow is good over both heaters.

By the way, what is the temp of your tank and the lowest temp of the room that it is in?



__________
"To steal ideas from one person is plagiarism; to steal from many is research."
researched from Steven Wright

So one of them would be sitting right next to the intake and parallel to it? I only have 1 filter, a penguin biowheel with two outflows.

Hi,
I have a 30G tank with an AquaClear 150 hanging on the back
of the tank in the center of the tank. Sitting along side
the filter, on the output side, is the heater.
At the other end of the tank is the UGF power head.
I have plenty of circulation and the heat is carried
throughout the tank by the currents. I dont see the problem
with hanging the heater along side the output side of your
HOB.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--