3-watt or 5-watt / gallon rule

[acorn54]

just checked my 29 tank with a breeder pair and found the water temp. at 90 fahrenheit when the setting on the heater was at 84 so i threw the heater in the garbage
in ordering some new heaters i think i remember on this board someone said they used the 3 watt per gallon rule. so i went ahead and ordered heaters based on this.
i also read in some fish books years ago that it is 5 watts per gallon when using a heater.
i would like some feedback on what other discus folks use as watt per gallon rules for their tanks and the reasoning behind it.
acorn (guy)

[hirst_cb]

if you have a 100 watt heater in a 29 gallon you will be good but 150-200 watt heater would be the best bet for you. good luck my heaters never match exactly - they seem to be 2 degrees lower all the time


chris

[roger]

The only major thing that I can think of is how fast you heat your water and if you can keep a temp when the air temp outside drops.

The titanium based heaters seem to do a better job of transfering heat.

If you can I would recommend the 150 watt Won Brother (Pro Heat) heaters. That should give you enough punch to maintain the heat and your heater doesnt come on and stay on for as long a period of time.

Not to mention down at the lower wattage range the cost of the heater isnt going to be that much different from its lower wattage cousin.

Peace,
Roger

[slicksta]

the 3watt/gall works fine for me...but again you have to take into account ambiant temp.
I've had best results with 100-200 watt heaters. Below 100 they just wouldn't heat and over 200 they burn out. Multiple heaters on large tanks is best. Most heaters are not exact to there dial setting...but if it can hold a temp constantly...that is what you need. So if you need to set it to 80 to hold a temp of 84....that's OK as long as it is constant. You may want to hold onto the old one if you don't stock a few back ups incase one fails.

[Carol_Roberts]

I tend to lean toward 5watt per gallon

[Cosmo]

A great deal depends on the environment in which the tank is placed. Stable temp environment requires less than an environment that is less stable (like a basement). 5 watt / gal is the minimum IMO.

[SmellsFishy0]

might wanna consider what kinda temp gage u use as well.......stick on ones that go on the outside wont get u as close to the right reading as the ones for the inside of the tank.........IMO-----AndyM

[limige]

THAT RULE DOESN'T APPLY!

when heating to 84-90 degrees! if you check out the back of the boxes at the store there is a chart.

you must figure the max temp for the tank, lets say 90 for treatments.
and find your normal room temp lets say 72

so you must raise the water temp 18 degrees from room temp. acording to one handy it would take a 170 watt or so heater to do that with proper on/off cycles..(you don't want it on constantly)

i use 100's on mine, haven't hit a winter yet with them. cary used 50's but i think his basement was always pretty warm. mine gets to 68 or so.

if your room temp is 74 and you want to heat to 84 it would take a 100watt heater.

hope this helps.
mike