Chimiclean

[avi3386]

Question about the material Chimiclean
Can i use it more than 48 hours to make sure all the Algae (red) disappear then replace water?

[mcgyvr]

Per the instructions after 48 hours you can repeat the dosage.

Its recommended to do a 20% water change after the first dosage but you could just wait until after the second dose to change the water if you want.
I have used it a few times and never change the water after using it.

[bertoni]

I'd have plenty of water on hand for changes, and also I'd siphon out as much cyanobacteria as is easy to get, to limit the amount of rotting microbes in the water column. I agree that you can repeat the treatment after 48 hours.