Circulating Bath Cleaner

For those of you using a circulating bath with water as part of an apparatus, what are you using to clean it? I have a polyscience bath, and I use the polyclean clarifier as an algaecide to prevent buildup. However, I still get some buildup after a while, and I am looking for something akin to a fryolator boil-out product. Polyscience used to make a bath cleaner, but it’s been discontinued. Have you folks used anything else?