My girls stopped drinking!

So last week I tried including a bit o powdered hydro nutrients into my tank. A few days later I noticed a film developing on the top of the water. I dumped the water and went back to my normal botanicare nutes. Since the film developed there has been a significant drop in water consumption. They use to drink 1/2 gallon or so a day and now they seem to not drink anything. I've tried using clearex twice and still nada. They are in mid-bloom right now so I expect some diminished thirst but this seemed a bit extreme. Many of the leaves have yellowed prematurely but some of the newer growth remains green.

Any tips to get them to start drinking again? I'd hate my girls to become full on anorexics..

I would run clean PH'd water for a few days. Kinda reminds me of a lockout.

I'll try feeding straight water and see what that does. Thanks!