Question about pump purchase....

[Bifferwine]

Not all internal pumps will heat up the water. If you buy one that has a tendency to heat up, it may heat your tank up enough that your heater won't have to work as hard. If you want an external pump, your sump will have to be drilled for it. Most sumps aren't, so most people use an internal pump.

If you read descriptions of pumps, many internal ones will say "will not heat up the water" or something like that, because it's usually considered a bad thing.

[fatman]

All submersible pumps will produce heat, as will all external pumps. Submersibles have nowhere to channel that heat but into the water, an exrenal pump can channel most of the heat to the surrounding air. Turning electricity back into mechanical energy (electricity into a pump) is far from 100 percent efficient. That is why most electric motors have built in fans. That and the fact that heat further reduces a motors life expectancy. A submersible pump could be more efficient, however aquarium submersibles are basically just the same pumping design as external pumps. Basically they are both just centrifugal pumps. The submersible is just sealed. Anyway that is probably more than you wanted to know. Pumps put out heat constantly therefore it will be putting out heat when other heat sources are supplying heat. Such as your lights. Heaters are really most important because they provide consistency. They should allegedly always keep the tank water temperature the same. Picture your tank during the hottest part of summer, without air conditioning, with the lights on over your tank, plus the pump heating up the water. Now figure that your pump is a 100 watt pump and it is probably 60 percent efficient (really that is a good efficiency). So that is 40 watts of heat going into your tank 24 hours per day. Of course if it is to much heat, you can use a fan to cause evaporation from your tank to provide cooling, but then you have to pay for running the fan. Viscous circles everywhere. Submersible aquarium pumps are cheaper to produce and are therefore cheaper to purchase. Not better or more efficient, just cheaper. Not cooler running (they both basically produce the same amounts of heat), but cooler to the touch as water is a better thermal conductor than air (meaning water holds and transmits heat better than air). Remember also, that powerheads aso are putting out heat. They are even less efficient than larger submergible pumps. Probably around 40 to 50 percent efficient. I live in Alaska and I still have heat problems with my 120 gallon tanks at times (summer), and I do not use power heads, although I am presently using TurboFlotors in tanks and they require submersible pumps. I run around four hundred watts of external water pumps per tank though, and using submersibles would be like running a 160 watt heater 24 hours per day. The only thing 100 percent efficient with a tank is the electric heater. You put 100 watts of electricity in and you get out 100 watts of heat energy out. 1 Watt per second in gives 1 Joule per second out. They are essentially the same.

[AngelLeah1981]

whoops sorry.