I have a 100 watt in my 20 gal that works great! but i need one for the 10 gal now that the fish are living in it. (they are in a storage/utility room at 77F and i want to keep them near the 80 mark. is 5 watt a gal a minimum or recommended? As in if i get a 150 watt for the 20 gal could i pass the 100 wat to the ten gal or would that be too much wattage...? ( i mean i know its too much wattage based on the 5/g) but will it hurt anyhting. heater or tank wise.

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When you pay that cash or swipe that card you are making a bond with that animal that you will treat it with love and respect, and its needs will be met, first and foremost (unless you have kids...) I don't care if you have to eat ramen noodles or nothing at all to feed your cat dog fish rat whatever. That's the bond you made! Life is precious!

On the back of most heater boxes it will tell you what you need. I have a 50 watt for my 10 gallon because I have no need to need to go 10+ degrees over room temperature. If I needed to adjust the heat that drastically I would have needed to get a 100 watt heater. It said it right on the back of my box.

My suggestion is to get a heater rated for your tank or get one rated for a bigger tank.

You could pass the 100 watt over to the 10 gallon and use the 150 on the 20.

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Hello Z...

For a small tank, you're right, just figure 5 watts per gallon of tank volume. So, if my math is correct, your 10 G will be fine with a 50 watt heater. It won't hurt to use a heater with more watts, but it may be too tall to fit vertically in the tank.

Just a thought.

B

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Low Tech Water Building Keeper

Good to know my math was right on the wattage. I think i will get a 150 for the 20g and pass the 100 down, the one i have is submersible and is quiet small considering its wattage so it should fit in the 10 gal tank. The winters are cold here, and the 100 watt in the 20g runs almost constantly to keep the tank at 80. Granted it is in the corner of the basement, but i have it insulated with foam from the back and sides. in the summer it does great though! but i figure if i am going to buy a heater might as well be a bigger one for the 20g that is all the way cranked up and running nonstop.

__________________
When you pay that cash or swipe that card you are making a bond with that animal that you will treat it with love and respect, and its needs will be met, first and foremost (unless you have kids...) I don't care if you have to eat ramen noodles or nothing at all to feed your cat dog fish rat whatever. That's the bond you made! Life is precious!

check this too:

Aquarium Heater Size Guide
Aquarium Heater Size Guide

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Hoopman
Sunny Orlando FL
55G W/Angel, loaches/cats, tetras, rasboras, Two Bio Wheel 350's (8 cartridges and 4 wheels) Dual T5 ATI bulbs which are blue & blue-plus (white), give a saltwater tank look/moons. - 37G w/Angel, Mystery snails, tetras/cherry barbs. Dual 24 inch T5 with same ATI bulbs/moons. Bio wheel filter (dual cartridges and one wheel) and Aqueon single filter Bio cage cartridge, both designed for larger tanks. n