Hi i used a 250 gallon aquarium along with a seep wall along with temporay outside coverings biggest problem was overheating during daylight . Final solution to that was to only partially cover the outside Since most of my colletion in now in the trees I use temporay frostcloth structures two are heated by infra red with thermostat. Still have to open up a lot of the structures following the cold front but does stay below 85 even in full sun. last year 42 was the low so were not used at alllol good luck with finding a system that works lol gary

Hard water isn't bad for plants except for those needing acidic soil like blueberry. On those rainwater is better. If using hard water it needs to be acidified to pH ~4.5-5 with sulfuric acid or vinegar. Salty water is bad for all plants. But that's about sodium chloride whereas hard water contains calcium bicarbonate. Filtration won't cure either problem. Dissolved salts can't be filtered out by ordinary means. Use an RO system if you think that's necessary but it's not what I'd do.

I was curious to see how my water would compare to yours. Our water system measures the hardness of our water in grains. That 180 ppm equals 10.5 grains and our water system reports our water is 40-42 grains hardness right now, roughly 4 times their designation of very hard water. So, I am in the ballpark of the hardness of your water. These are things I can tell you. For my vegetables, I do not use softened water. I could not afford to use the potassium chloride for my vegetable garden. Since my soil is compose of the same stuff the aquifer is made of (limestone), I have determined one of the best things I can to do for truly excellent results is to amend the soil as much as I can afford to do (incidentally, with the low rain fall, the soil is low in organic matter). I find a great mix of things to more helpful than say, just grabbing horse manure from the neighbors. Peat moss, cotton bur compost, plenty of straw on top, etc. The water does play a part, so in your shoes, I would think short-term and long-term. I forget the exact numbers, but RO water takes something like 3 gallons of water to make 1 gallon of water. That is a lot of waste. Over the long run, the more water you take from the well, the greater the likelihood the quality will decline and the water will get worse. That is why it is likely a good idea to work on the rain catchment to at least use in conjunction. For those of us who have made our homes in arid regions, it requires more from us to find ways to live sustainably. I understand the expenses because I too am trying to figure out a practical rain catchment for my house and gardens (I also do not underestimate what it is like to haul water, as I bail 5 gallon buckets of water from my kids bathtub and carry it downstairs and outside, a 5 gallon bucket weighs almost 40 pounds, it really sucks but my arms look great!). Just some thoughts.

The top of the panels should be sealed with waterproof sealing tape, as you have found out. The bottom of the panels should be sealed with vented "breathable" tape that allows condensation to seep out, but keeps insects, etc. out of the panel channels. If the top of the panels are not sealed, then you are also losing some of the insulative properties of the twin wall panels. Drilling holes in the bottom would help remove the water, but not solve the basic problem. Removing the panels and sealing properly would be the best solution.