How do you apply aluminum sulphate to a swimming pool?

Answer 1

Aluminum sulphate is a floculant and these is generally cast evenly as possible over the surface of the water. the material will then work it way down to the bottom of the pool attaching itself to impurity's as it does so. if the remains undisturbed for a couple of days a cloudy layer forms along the bottom which can then be vacuumed to waste.

Answer 2

Alum is recommended for use in a sand filter but not a cartridge filter as it will gum it up. Because cartridges will only filter out about a 15 micron particle sometimes a pool will have a lot of particulates that pass through the cartridge. Especially if it is more than two years old. You can get some temporary help by adding a scoop (1lb.) of DE (diatomaceous earth) through the skimmer. This will drop your particle size down to about 3 microns. Clean the cartridge after the pool is clear. You may have to clean the cartridge a few times. Watch the pressure gauge on the filter and when you get about 8 lbs. higher than when you started, clean the cartridge and add another scoop of DE and keep doing this till the water is clear. If you need to superchlorinate to kill algae do that first.