Here is a step by step guide on floccing your swimming pool:
1. If you have a multi-port valve on your filter, shut off your pump and turn the valve to “Recirculate” or “Recycle". This will stop the water from flowing through your filter. All this does is spin the water around to help mix the chemical in.
2. Add the recommended dosage of Flocculant to your pool. Floc comes in liquid and powder form. Make sure you check the directions for the right dosage for your size swimming pool.
3. Circulate the water for about 2 hours to get the chemical fully mixed in, then shut off your pump and let it sit overnight. During this time, the chemical will start to bind the particles together and settle them to the bottom of the pool. In the morning you should wake up to a nice healthy particle cloud at the bottom of your pool.
4. Hook up your manual vacuum cleaner. Before you turn your filter on, make sure you have your multi-port valve set to “Waste.” When you vacuum this thick cloud OUT of your pool, you don’t want that thick water going through your filter.
If you have a cartridge filter, unfortunately you do not have this waste option and all this gunk will go through your cartridge, more than likely clogging that cartridge filter element up to the point of no return and needing to be replaced.
We do not recommend floccing your pool if you are working with a cartridge filter, unless you plan on replacing that cartridge filter element when you're done, which can be quite pricey, anywhere between $60.00 - $150.00.
5. Add your garden hose to the pool and turn it on while you vacuum. Since you are vacuuming to “waste” which will dump a lot of water out of your pool, it’s best to have your garden hose replacing the water with clean water as you vacuum out the dirty stuff.
6. SLOWLY vacuum the bottom of the pool. You’ll be sucking out this thick, dirty sludge from your pool, and as you move the vacuum across the pool floor, it’s going start to kick up debris. When it becomes to cloudy to see what you’re doing, shut off your pump and let it sit for a couple of hours to resettle. Then you can go back and continue vacuuming. You may have to to do this several times depending on how much debris you need to vacuum.
SEE ALSO: How to manually vacuum your pool
When you are done vacuuming the pool and everything looks good, I would suggest double shocking (2-3 Litres of acid over a space of 48 hours and adding 2-3 cups/600g of granulated chlorine) your pool to make sure ALL the algae has either been removed or destroyed.
METHOD #3: POOL ALGAECIDE
There are some good algaecides which directly kill algae, though they are pretty much a glorified combination of Chlorine and Acid. These algaecides may have to be added in large doses depending on the brand and can get expensive. Unless you're using specific black spot algaecide for a specific black spot issue, Hydrochloric Acid dosing and bumping up your chlorine should also do the trick.
You can add 200ml every week to prevent algae from growing in your swimming pool. Also, algaecides tend to include metal bases, and you don’t want to add too many metals to your swimming pool. Metals in your water can cause staining.