Why do you get dirt back in the pool when cleaning?

There are a few ways to get rid of dirt in your swimming pool. Firstly there is a chemical that you can get in which will force all dirt suspended in the water to sink to the bottom. To clean the bottom of the pool for the first time, you will need a swimming pool hose, a vaccum head and a telescopic wand. All are available from a pool shop. You plug the vaccum head onto the telescopic wand and plug one end of the hose onto the vaccum head. Leave the vaccum head sitting over the water. Turn the filtration system on. Take the free end of the hose and fill with water by placing over a return jet. When all the air is out of the hose, take the free end and plug into your skimmer box. You will now be able to vaccum your pool by running the vaccum head along the bottom of the pool. Once clean, disconnect all equipment and backwash the pool. The pool should now be clean. Afterwards, you could consider buying an Auto Pool Cleaner - they move by using the filtration system and clean whenever they're in the pool. The only thing to remember though is that you will need to backwash regularly, since it is always cleaning the pool.

The chemical is a floc which is mixed in a bucket of water and spread of a maximum surface of the pool while the filter is operating for several hours on "Recirculate". Then turn off filter for a day or two to allow the sediment to settle before vacuuming. When vacuuming the sediment from the floor of the pool, do not vacuum through the filter. Vacuum to waste.