My WECO RO filter puts out between 1 and 5 PPM. It takes about 8 hours to make 60 gallons at 65 PSI input pressure.
Get a storage barrel with a float valve in it so you can store filtered water. This way a slow filter is not an issue. Set it on some cement blocks, put a valve in the bottom side for getting water out. Toss a pump in there to mix the water so it's not stagnant. I actually mix nutes in the barrel when it's full, I shut off the input valve that feeds the float. Add nutes. pH. It's enough water for 2 days in one of my rooms. I have a 30 gallon barrel in each flowering room and a 55 gallon barrel in my veg room. Below is a pic of one of my 30 gallon barrels.
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