I use Sodium Hypochlorite as my main source of Chlorine but once in a while use TCCA 90% Tablets to maintain the Cyanuric Acid level.
My Pool Chem supplier is now offering what they call "Magic TCCA" tablets which are a mix of TCCA, Alum and Copper Sulphate. The specs are:
Available Chlorine - 83%
Aluminium Sulphate - 4%
Copper Sulphate - 2.5%
PH Value - 2.72
Has anyone used these? Is there any downside to using these over the regular TCCA 90% Tablets? I do maintain 50ppm borates using Borax.