I've used Reef Crystals for the past two years+, and I've never had cloudy water for more than a half hour. My RO/DI water is usually around 62F, and I always mix it cold. I'm only mixing 25 gallons at a time, so it's much easier to churn it than 100 gallons would be. I use a 2400GPH pump laying on it's side on one side of the 30 gallon vat, blowing across the bottom. An 1100GPH powerhead at the top on the other side helps with the heavy gyre action. I use a large spoon to stir up any salt that makes it to the bottom. There is heavy agitation, so I get a good, clear mix in about 20(ish) minutes. I let it stir for 24 hours before use, but I could use it immediately if I wanted, or needed to, as I certainly don't have to worry about oxygen/co2 equilibrium.
You didn't have this problem when you were mixing 50 gallon batches using a Mag-Drive 12, did you? You've doubled the volume of water, and mixing with basically the same equipment as before. Actually less, as the Quite One 4000 is rated at 991GPH (yeah... right). Naturally it's going to take a lot longer to get a good blend. If you want it to mix like the 50 gallons batches, you'll have to double the flow of the equipment you used. Instead of a 1200GPH pump, you'll need a 2400GPH pump to get equal performance in 100 gallons. I have twice as much flow in my 30 gallon vat! The harder the water churns, the faster and easier it is to mix in cold water. You always want your water cold while mixing, so you don't have elements precipitating. Looks like you need a bigger pump, bro... a MUCH bigger pump.
