I am just starting to give H&G Dip Clean a try and mixed it into my 40 gal. rez after my nutes and ph adjustement. I have an air stone in the bottom with a lid on top of the rez. The rez will usually last about 5 days. When I checked it the other day when it was half full I noticed a white film all along the inside of the rez, which I am guessing was salt build up. Is this normal? Does this mess with the suspension, availability, and amount of nutes in my mix? I did notice that when I mixed a new batch of nutes without cleaning out the rez, that a lot of the white film came off from the sides and were mixed into the solution. It looked like little white flakes floating around. Any experience with this? And how do you like this product?