We were the same as you, paid $60 for a pool man to come out and go through everything with my husband, testing, maintenance etc, we now know what to do, we take a sample to our local pool shop and then but salt etc from bunnings as cheaper. If the pool needs anything other than general maintenance we get the owners to sort it out. It's worth paying to get a good knowledge as said above a green pool is a nightmare, pump now on 8 hrs a day as summer mode, but we run 4 hrs of it at night as cheap electricity, sooooooooooo worth it as children and husband now in it every day