Try soaking the ineffective carts in Cascade automatic dishwasher detergent, the powder. If that doesn't work, try soaking them in Muriatic Acid--what have you got to lose if they are clogged anyway?

Switching over from Bacq may be your best answer. Be prepared with lots and lots and lots of chlorine...I'd suggest getting the 5 gallon carboys of 12% from the pool store--there's usually a deposit on the carboy, but you only pay it once. I'd get two and as one was empty I'd get a replacement--it may cost a little more (maybe not--depends on prices) but disposal becomes a non-issue.

Normally, I'd say just buy the bleach, but with the amounts you'll need for the switch, the carboys may make life MUCH easier. Besides, if you can get 12% for $15, that's like getting 10 gallons of Ultra bleach for $15.--$1.50/gallon. Around here, Ultra is now running $1.80/gallon (.45/quart).

I only said that those are the possible reasons for your yearly purchases.

I have never understood the attraction of Bacquacil, or Bromine.