Fishermann- "Krish if your tank is sitting in a 81 deg. room your tank is going to stay atleast 81 deg. I would get a chiller for the tank. I live right in front of the pacific ocean in Wash on Pidilla bay and we have tremendous humidity, I run 2 dehumidifiers pretty much continually in each end of the house. I haven't seen the rise or fall of humity make much difference in the tank temp, it is the room temp that can make a big difference. Water evaporation is not the issue as much as getting the heat out from under that canopy when those MH's are on. My experience has been when the heat outside goes up the a/c comes on more often, not if the humidity changes. If your room temp is 81 your tank is going to stay 81 unless you can control it seperatly some how and that is with a chiller, lights on or lights off period, it isn't any pumps or motors it is room temp period!"
This is some terrible advice. You need a little thermodynamics before you misslead people like this. Warm air above the tank? Pff, thats one of those <5% heat source things, not an issue. Cooling air around the tank? Also one of those non-issues, if anything, AC drops tanks temps becuase it removes humidity.
Secondly, you could easily drop a tank below room temp with evaporation. This stuff about a tank not going below 81 deg in a 81 deg house is just completely incorrect.
Ok, let me try to break this down for the 10th time. This will be the last time, and then I'm just gona ignore it.
For water to evaporate, it requires an energy source, as its an endothermic process. The only place the water has to draw this energy is from the heat energy in the tank. This means, as water evaporates, it lowers the temp, and in a very substantial way. All the warm or cold (with small delta-T) air you want blowing over the tank you want removes or adds piddly little amount of heat. When you evaporate water however, you remove massive amounts of heat.
For example, have you ever seen a swamp cooler? Its a fan blowing on a giant flat wick of fiber paper sitting in a tub of water. They easily get 10+deg below room temp, and supply a nice cool breeze in a room. How are they below room temp if only warm air is hitting them? Because of the energy of vaporization being taken out thermally from the water to let it evaporate.
Now, what happens to a swamp cooler when humidity hits 100%? Nothing, its useless, no more cooling.
Ok, one more thing, human beings cool through evap cooling. For example, lets say we are in a 110deg day, and we are expending physical energy, which releases lots of heat. Our body is able to maintain 98.6degs because we sweat moisture onto our skin. Now, does warm moisture on our skin do anything to cool us? Nope, not a bit. So, how does it work? When the sweat evaporates it sucks tons of heat out of our skin, which is how a body can be internally generateing lots of heat, let staying well below room temperature because of evaporation.
Likewise, a human can stay cool and survive for many hours in 140deg+ dry heat, because sweat evaporates easily and sucks the heat out of the body. Where as humans can die of hyperthermia in just a 100 deg enviroment with 100% humidity, because the body is steadily making energy, but its neat cooling system doenst work.
Ok, thats the last of my talking about it. I hope maybe 1 person learned something.
-Luke
Here's a joke...How do you know you are a blonde? When you spend a week trying different things to cool a tank before reading the actual room temperature!:lol:
