Interesting Stuff...thanks for the responses Here is what I am facing (in Western Oregon) Yesterday... LOW 29 HIGH 45 OK, to me neither the soil temp or the air temp would be conducive to plant growth...even a cool weather crop, such as peas. Under these conditions, it was not raining but the sun didn't appear until late afternoon so things never warmed up. I have been gardening for (only) six years so my experience is limited, but my observation is that peas planted at this time do not germinate well...therefore I went to starting them in cell trays. They are my unheated greenhouse now and are growing some there. I would say yesterday's range in there was (like) 34 to 65. I don't want to go to "analysis paralysis" ...but there might be a useful quantitative number that I might use...any other thoughts welcomed

Really nice ! Very attractive ! My pond is kind of disorganized and lately since it has been drought conditions - I've added a dwarf banana and two palm like succulents - so it has a miniature oasis effect. I'm no math wiz - but your question about other features which I don't have - except for a return from the inground filter - raised for splash effect and the pump fountain (turned low so the filter gets most of the pump water flow) - makes me think that having the waterfall flowing over warmed slate and being shallow - evaporation rate would be more. My pond is shaded a bit more than half the day. But it is still miserably hot during the day - even the toads and frogs, fish too, are not visible much during mid-day. All the care you have taken with building your pond - I think it is just evaporation and not a leak. Global warming around here - no joke! :-)

I don't use aquarium water pumps, I use fountain/pond pumps. And I never bothered to check, but I still have the box. The largest one I have pumps 500 gallons per hour, with a maximum lift of 8.7 feet. The power consumption is 35 watts, and 0.6 amps. This pump is larger than I need for any system I have done so far. In fact I usually need to use a "T" connector and run half the water directly back into the reservoir so it wont overflow the systems. I mainly run flood and drain, or drip systems (as well as water culture systems that only uses a air pump). So my pumps are never running for long periods either. At most 30 on, and 30 off (50% of the time) during the hot parts of the day in the flood and drain systems (with only one or two cycles during the night). The Drip systems usually have enough growing medium to keep the roots moist for hours, even during the hot part of the day. So those usually run 30 on, and 2-3 hours off. I can see how the theory of a external pump being able to dissipate some of the heat through the casing and into the surrounding air, rather than directly into the water if it was submersed makes sense. But at the same time if the surrounding air is warmer than the pump, there wont be any dissipation of heat into the already warmer surrounding air. And it would be pointless if the air temp wasn't significantly higher than the water temp, otherwise the ambient air temp would be enough to keep the water temp in range. The pump would need to put out a significant amount of heat to make a difference. But using the pumps I do, and from simply touching them after they have been running for a while (that I often do). Like every time I do a nutrient change, and take them apart and clean them each time. I simply have never noticed any noticeable heat from them. I would need to do a side by side controlled experiment using identical water volumes, starting water temps, air temps, and containers. Then run a pump for hours in one of them, then compare water temps to see if there was any difference between the two. Even if there was I cant see it being more than 1 or 2 degrees at most. At least with the pumps I have. grizzman I guess it depends on the pump/s your using. The pumps I use/have would need extensive modification to attach a housing that I could attach a hose to the water inlet side (and that was durable enough to last), and it would need to be gravity feed into the pump. Unless it was going to make a significant difference, I just don't see the effort being worth it. As I mentioned I haven't noticed any significant heat coming from the pumps I use, and 1-2 degree change at most isn't going to make enough of a difference to me. The water temps I deal with from late April to early October need much more cooling than that. But I'm sure under the right circumstances that could be useful.

Hi Betty heres a trick you can use to cool the COW. Get a piece of burlap to go around the COW and soak it hang it on the outside of the COW the evapotation process will cool the air under and around the sides of the COW 10-20 degrees. The air intake is in the legs of the COW and thermal convection will draw the cooler air up into the COW. Make it so it goes from the ground to the lid lip. Paper clips fashioned into little hooks will work to hang it on the COW. Wrap it completely around the COW. If you keep the top off you will need to check and keep the burlap wet. This will increase the humidity in the COW but if its dry the bedding will not dry out as quickly and the surface will be cooler. Pick up a little thermometer at Walley World with a short probe and check bedding temp. 80 deg F or less and the worms will be fine. This method of cooling is called swamp cooling and was used before the present day air conditioners. I think its still in use in some places today.