Original (many months ago) I had planed to use a high volume RO system. One like
Merlin 700 gallon per day reverse osmosis system, but besides the fact that it would still take about 12 hours to get 300 gallons out of it. The biggest issue and main reason I wont be using it is because RO systems waste a lot more water than they put out (4-5 times more). Living in the desert, and one of the biggest advantages of growing hydroponically is that it uses much less water. I just cant justify wasting all that water.
So I'll be building a custom water filtration system, with replaceable cartridge filters. It will have 4 to 5 canisters like these
GE Household Water Filtration Unit. Starting with a pre-sediment filter to get most of the large particles. Then it will have a "absolute 1 micron filter," the 1 micron filter will catch the small particles like fungi spores. But it needs to be a "absolute 1 micron," if it dosen't say "absolute," some spores can still make through. Then it will have the activated carbon filters, including ion exchange for getting minerals. After the custom water filtration system. Each reservoir will have it's own UV light filter as well, for pathogens, bacteria and fungi. Weather it's from the source water, or enters the system from being airborne.
P.S.
Thanks for the other options. I have only recently started using the hot glue for sealing hydro systems. But so far it's the best option I have used to date. Though the real test will be repeated summers in our heat. I know silicone wont work, it's just to flexible, and it peals off easily (I have plenty of it). But I'm defiantly going to look into using the Marine Goop and LEXEL as options also.