LegoZ81-There are GFI outlets as the lead outlets on both circuits that run down the sides of the greenhouse (for all of the outlets). The dedicated outlet for the blower is also GFI. I have a ten foot grounding rod for the house, ten footer on the greenhouse panel and eight footer on the generator. I do appreciate the info on checking for stray voltage and your contribution.
seldon-after recharging the deionizer, I have run about 150 gallons with the tds measuring from 1 to 3. The color is changing pretty rapidly though and will probably need recharging again before the RO units get here.
Unresistible Blue- just using regular limewood air diffusers. I usually use Lee's on my aquarium but am trying out Aquamedic brand on the greenhouse skimmers. If there is any difference, it's hard to tell because the skimmers are sized so differently and the vat is cycling fresh rock so there will be a ton of stuff in the water anyway.
scubadude-Thanks for all of the kind words, encouragement, and consider it inspiration returned. When I was doing the initial phases of research, your greenhouse construction, along with people like Dendronephthya, Treeman, and of course Calfo, was one of the ones inspiring me as well. Glad to have you along. H2OENG has made some valuable contributions in this thread for sure. The salt method is pretty straight forward. All of the specifics and how efficient it would be haven't been worked out yet. Some sort of container that would allow air to pass through would be placed outside the shutters and filled with salt. As the air comes in the shutters, the salt dries it thereby allow it to accept more moisture from evaporation. Theoretically, this would provide for a greater evap cooling capacity. I did check into some industrial desiccants but don't seem appropriate. Most of them are used in shipping applications for a short time. Others I have seen are used in combination with huge rooftop AC units like on large resort hotels. They are expensive for large quantities. They can be dried and reused but would require extra use of gas to have burners to dry the material or haul several hundred pounds back and forth from my household oven. That is not really an option either. It takes hours at 350-400 degrees to dry them and would take multiple loads in the oven and probably take a whole day to accomplish.
I am seeing now that the pool comparison isn't really appropriate. 13,500 gallons can't compare to even the 425 g live rock vat sitting in a greenhouse. If there are 2 or 3 days of cloudless skies, the temp in the vat creeps up to around 84, which by my way of thinking is pushing the limit. It seems like the sunlight itself, no matter what the temp in the greenhouse, contributes to heat gain in the water. Right now it's easy enough to compensate for by setting the shutters to open a little cooler, but come summer?....A man from our local club, Tschopp, had posted some good info about evap cooling in this thread. Geothermal is something I had read about in your construction and Treeman's but hadn't really considered it for this project. I'm not sure of the freeze line but would guess it's probably somewhere around 32"??? When I was plumbing, we were required to bury water lines four feet. Maybe someone in the club could speak up here if they know about the freeze line. Geothermal would have some potential here, the tap water temp at this time of year is around 55. In summer, it might jump up about 10 degrees. After the loop through system water and picking up heat, the warmer water could even be sent through the RO and increase it's efficiency.
I am on city water (technically) but it is just a series of 6 wells that is pumped up to the water tower. As far as I know, they just use chlorine and no other treatments. The water is very heavily laden with rust and it's a highly agricultural area so I'm certain it has phosphates as well. I have the town's water report for the last three years and the EPA report for my town's water but am pushed for time tonight and can't go dig it out right now. I'm thinking that any well I could drill would get the same water. I did have some trouble adjusting the water height in the skimmers. Mainly, I think, because I used ball valves instead of gate valves. One little movement of the ball valve resulted in a big difference in water height. I put some threaded adapters on the outlet ball valve and found that by turning the pipe up or down, I could get much finer control over the water height in the skimmer. I also added some 3" elbows to the bulkheads that feed the skimmers. The bulkheads were submerged and were not pulling water from the surface which left a ring of gunk around the vat. The ring is gone now. Don't hesitate to contribute, that what this thread was intended for. No body clogs it up by sharing information we can all gain from.
http://www.tampabayreef.com/03-15-2003.html
There are many catch 22's which im sure you are realizing to some of these approaches. I hated the idea of plumbing my skimmers inside the GH which I did like you. But eventually plumbed them outside the GH and want to (next go around) play with partially burying the skimmers, as I am thinking this may stabilize their temperature.
ZAP!
Glad it went to a good home! 
