snadaud- According to the engineers I talked with (like you, I am no expert), it is evaporating water which lowers the temperature of that WATER. Whether that water is in an aquarium, a reservoir for an evap pad, a lake, wherever. In our tanks, we use evaporation to cool the tank water (water turns from liquid to gas, taking heat out of the water). In an evap cooling system, the water is pumped across the pads and gets evaporated which cools the water in the reservoir which in turn gets pumped across the pads (water turns from liquid to gas taking heat out of the water). As the incoming air flows across the now cooler pads, the air gets cooled (plus picks up moisture as the water evaporates from the pads into the air). The water in my reservoirs for the evap pads is very cool to the touch when the shutters are open and the pads are receiving water, usually in the 60's F or 70's F when it is over 90 F outside temp. The only drawbacks with this system is that when the ambient humidity gets too high, the pads become less effective because the incoming air can't absorb much more moisture and they don't cool the incoming air as well. As the air passes the pads, it also picks up moisture, which lowers the ability to pick up evap cooling from the tanks themselves (the air coming into the greenhouse is now more humid). If the pads are working efficiently, the air temp inside the greenhouse will be kept low enough that it won't matter if we can evaporate water from the tanks or not.
The opposite function is also true (according to the engineers), that if we remove water from the air, the air heats up. What you are saying is true, it takes energy (heat) for water to change states, from solid to liquid to gas to liquid to solid . The difference is in which way the energy (heat) flows, either from the air into the water, or from the water into the air.
There is much more discussion about the cooling aspects here, about 35 pages
http://reefcentral.com/forums/showthread.php?s=&threadid=465933
be sure to check out the psychometric chart, print a copy for yourself, it will come in handy.
Hello Treeman,
glad to see your rebuilding is coming along.
Just to add, I am using the Klerk's K-50 clear (all the way around) as well. I find that I have to shade everything with the exception of Sarcophyton elegans, but those corals can grow in ankle deep water in the tropics. I don't have any stonies stocked in any tanks yet either. Even in winter, I had some Actinodiscus mushrooms trying to bleach. Very strange though, there would be some trays with one or two mushrooms trying to bleach, and the rest of the tray would be fine. Other trays, the entire population would try to bleach. Other trays, the entire population would be fine. All trays in the same tank. I haven't lost anything (YET), so I am grateful for that.
P.S. You going to IMAC this year?
The UV blocking is just horrifying for many of the corals you are likely to want to keep/grow.
