Pools been up and running for a few weeks now with no real issues. I decided I had better check the chlorine in the cartridge and notice it was just about gone. Used my test kit and saw I was at 2ppm FC 0 CC. Ran to the pool store for another cartridge of Trichlor (just finishing out the season). My CYA is still maintaining at 20ppm but I did use pool math to calculate a 8.25% bleach add to get my FC to 4ppm before adding the cartridge. It seems to do the job at maintaining the levels but the price is stupid. Like $28 for 2 cartridges that will get me about 4-5 weeks.