Very nice setup.

Knock your PH down to 5.0 or 5.2 and it won't go up so fast.

When we first put clones in our drip with hydroton it does the same. We check it twice a day and bring it down. Seems when we only bring it down to 5.6 it rises back fast.

Don't worry about the acid it does not hurt anything. Not having it hurts.

We have used what comercial boys use sulfuric acid.That's right battery acid is what large hydro opps use for ph down.