# How many watts does my heater need to have?



## Manafel (Sep 4, 2011)

I am setting up (slowly but surely ) my 75 gal tank. I already have my substrate and filter up and going so I can have it cycle wile I wait. My next buy is a heater. I know there are quite a few different factors that have to go into picking a heater, but I want something that is fully submersable. I plan to(maybe) have cichlids. I have looked and I don't think a 300 watt would be enough. anyone have any ideas? *c/p*


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## JDfishguy388 (Nov 26, 2010)

I have a 100g with 2 Elite 300watt heaters and my temp never falls under 78.

your best bet is 2 heaters for even distribution of heat and in case one fails your fish dont suffer. 

Aquarium Heaters - A Guide to Everything About Aquarium Heaters

this link has a chart that will help you decide what is best for your aquarium.


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## jrman83 (Jul 9, 2010)

It is better to have two for even distro of heat, but a 75g will easily allow you to get away with one. You have to think about what temp the room the tank is in is going to be kept and the difference between that and the tank temp. Generally, just figure 5 watts per gallon. If you go with two, split what you need in half per heater. This way, if one fails to shut off, it won't cook your fish.

I use 2-300W heaters in my 125g. Seems to work pretty good.


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## Manafel (Sep 4, 2011)

ok thanks. I normally try to keep my apartment at about 72-76 in the summer and about 65-69 in the winter. During the fall and spring months I like to keep the doors open to aeriate the place. I know that the temp. variance through the year might seem pretty odd, bu I'm constantly fighting with my roommate(via the thermostat) about what temp it should be. -_-;; I'll probably just go with 2 heaters then. Does 200 watts a piece sound reasonable?


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## BBradbury (Apr 22, 2011)

Hello Man...

If I had your tank. I'd get two 150 watt heaters and place them at opposite ends of the tank. If your fish room temps stay pretty constant, approx. 68 degrees, then these two will be sufficient.

B


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## Manafel (Sep 4, 2011)

Thanks for the tip brad. But Idk how that would work because when I first set up the tank I had a betraying in it for a short while. I took the heater out of my 20 gal(I honestly don't know how many watts it is) and put it in the 75 just to see if it would do anything. After about 2 days of having the heater on full blast all it seemed to do was grow some kind of slime on the bottom of it and a small coat of the slime on top of the water. Needless to say I took the betraying and heater out and put them where they originally came from. Could that have just been because the tank was cycling?


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## BBradbury (Apr 22, 2011)

Hello again Man...

Because of the large amount of water you have in that 75 G, you won't get the temp changes you do with a smaller tank. So, heating the tank isn't as critical. Ideally, you have a tank this heavy in your basement, close to 750 lbs, where the room temps stay constant. I have three 55 Gs in my basement and can get by with a couple of 100 watt heaters in them, because the room temp stays at a pretty constant 72 degrees.

If you're not that fortunate, you'll need a little more powerful heater now that the outside temps are getting cooler. Someone may have posted this earlier, but a good "rule of thumb" for heaters is 5 watts per gallon of tank volume for smaller tanks around 30 Gs and three watts per gallon for the larger ones. For your tank, you'll need watts in the 225 range or better. With two 150 watt heaters, you'll have that plus a little "wiggle room".

B


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## snail (Aug 6, 2010)

Manafel said:


> ok thanks. I normally try to keep my apartment at about 72-76 in the summer and about 65-69 in the winter. During the fall and spring months I like to keep the doors open to aeriate the place. I know that the temp. variance through the year might seem pretty odd


Lol, my apartment doesn't have air conditioning or heating so it gets over 100 in the summer and down to about 45 in the winter, my fish have it better than me!


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## Manafel (Sep 4, 2011)

ok thanks Brad, I keep mine in my living room, but I'll do that 

Snail - Wow I cant imagine not having air conditioning in my apartment x.x


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## jrman83 (Jul 9, 2010)

On the other side of the coin....if the larger tank does get down to a certain temp, it will take a lot longer (sometimes days) to get it back to where it should be with lower wattage heaters.....not saying change, just something to remember.


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## stephgrim (Oct 12, 2011)

6-8 watts per gallon is a good rule of thumb, assuming you will need to raise the temp of the water 8-10F degrees above room temp.


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