I inherited a pool that was built in 1976. Its an inground 33,000 gallon pool that I have diligently been trying to get clean for the last 6 months. I've brushed everyday my testing levels all say that the pool water is good. I've shocked, I've flocced I've vacuumed and brushed. I've even vacuum to waste. Nothing works. The pool continues to have a layer of what I think is brownish dead algae on its floor everyday. The money I've spent is ridiculous. I've read every article, I test my own water and the results are always good, but the water is either cloudy or the floor is dirty ALWAYS even after daily brushing hours of it. I let the filter run 24/7 . I did notice after backwashing and rinsing that the jet ports are returning something dirty back into the water but it clears after about a minute. Do I need to replace the sand in the filter? I read that the filter is from 2006 so it probably hasn't been changed since then. Will changing it do any good? When I vacuums I have two skimmer baskets. I put a ball in one for better suction but the suction barely does anything . There is hardly no pull in the suction at all. So I end up brushing everything to the bottom and filtering to waste but even that doesn't work. Any help is appreciated I'm tired and ready to give up. I bought this place because of the pool, I was hoping to be able to swim but so far its only been a time wasting nightmare.