Very good, I have been using it for a while and it's worth the money. The only problem was with the shipping, they left it wherever they wanted instead of taking it to its destination as the order stated. Bad shipping

I used it for 2 months in a surface round pool and the water was free from greenness and algae while also giving it clarity. I did not notice any skin problem from its use (according to the instructions). The quantity is more than enough and with weekly use of 85-90 ml, it did not exceed one liter.