backwash problem!

[Traci]

I need some help with my 20,000 gallon inground concrete pool. My boyfriend is incompetent and is constantly letting it get full of algae and not cleaning it properly. About 3 weeks ago he backwashed the system like he was supposed to, but because it is has been so hot, a lot of water had evaporated out of the pool leaving it about 6 inches below level.... not enough to properly run the filter through the basket catches. (I am a little lame on terminology.) A week later, after the pool was not disolving and circulating the shock.... it was sitting on the bottom in scattered sections.... he opened up the lid where he put in the backwash power (diamatacious earth?) and it was in a giant clump stuck in that basket! It was all clogged in the filter paddles as well. He cleaned it all out, took everything apart, and still nothing works right. The pump comes on, the jets work, the automatic vacuum in the bottom of the pool works, but the pool is still green and will not filter any of the water. The psi's jump back and forth between 10 and 40! And, the little basket under the water cycle lid is melted! I have no idea how that could have happened! The pool is heated, but the gas heater has been turned off for a year. What do we do? Please help and thank you for any suggestions.[/b]