The second tank getting a wet test.
The cross braces on this tank were set up a little differently than the first tank. On the first tank, the lower two braces were located by dividing the tank into three equal parts. The top braces were then located by finding the center of those three equal parts. There is a longer distance between the braces, but an unequal length between the last brace and the end of the tank.
This second tank has three upper and three lower braces, so the tank was just divided into four equal parts. This left an equal distance between all three braces as well as the space between the end braces and the end of the tank. The extra brace in the lower position combined with the equal spacing down the length of the tank has made this one much straighter when full. I was satisfied with the first tank, I know it is sound and will hold, but this one just looks better. The difference is clearly visible.
Second tank.
First tank.
As expected, those evap pads from Atlas arrived just like clockwork. They are installed and operational. I also installed some actual pond liner in the troughs because I envisioned the vibration from the pump would wear a hole in the plastic that was in there for my initial experiment with the green pads. The vertical pipe was also shortened an inch so the pump doesn't sit on the bottom of the liner, it just sort of hangs there suspended off of the bottom of the trough. That should eliminate any chance for the pump wearing a hole in the liner.
I rigged a temporary semi-auto top off system.The pads are made of stiff corrugated cardboard (or kraft paper) and little bits of the material were getting stuck in the holes in the horizontal pipe. That is why there is a dry spot on the pad in the pic below. That problem was solved by simply installing the sponge screen on the inlet of the pump, and then cleaning out the holes in the pipe. The water coming out of the holes in the horizontal pipe let the water splash around quite a bit, so I cut some strips of the green material to wrap around the pipe and long enough to hang down to the top of the new pads. This distributed the water more evenly across the width of the pad and almost eliminated the splashing.
I do have the parts ordered for a real auto top off system. Only thing I expect to have trouble with is the fact that the tap water will have to be used for the top off. This will leave mineral deposits on the pads and shorten their life span. Right now, I am using the RODI water but those 58 quart (14 1/2 gallon) tubs only last about 3 to 3 1/2 hours and I have to run out there several times each day to fill them. The RODI can keep up with the need during the day (29 gallons every 3 to 3 1/2 hours), but that only leaves the night time to run water for the barrels and tanks.
The pads are definitely helping. The last several days, the outside ambient temperatures have been in the low 90's and humidity in the 55 - 70 % range. The temp inside the greenhouse has not gotten above 94 at any time. Having a peak of 94 inside the greenhouse seems to keep the tanks in the range of about 77 at night up to 81 at the highest. Remember, a week ago the temp inside the greenhouse was 96 when the outside temp was in the mid 80's with only the fans running for cooling. The big exhaust fan also doesn't turn on until about 9:30 am when it used to come on about 8 am before the pads were installed. When the exhaust fan first turns on, it only runs for a few minutes. The thermometer can literally be seen to be dropping, then the exhaust fan shuts off again until it really starts warming up inside the greenhouse, then it is on for good. The air coming in through the pads is around 76 - 78. Now maybe the evap pads won't give me the absolute ideal desired temp when the outside temp is above 100 and the humidity is very high, but I think it will help enough to keep the corals happy. If it starts raining inside the greenhouse, then I'll know I'm in trouble.