I have an ~15,000 gallon pool and when I opened it this year it was very green with a lot of debris in it. I have been adding copper algaecide, fresh n clear shock, and regular granular chlorine. While it is no longer green, there are a lot of suspended particles now and I cant seem to make any progress on clearing it up. I would say the visibility is around 18-24 inches down at best. I bought one of the recommended test kits I saw on this site and below are my results:
CYA <30ppm (I fill the tube all the way and can still faintly see the black dot)
Another serious issue I am having (which I believe is related to whatever is suspended in the water) is that my cartridge filter will not get clean. I have hosed it down repeatedly, soaked in it a cartridge cleaner bath, muriatic acid bath, and TSP bath all overnight with no noticeable change. The pleats still feel slimy to the touch and the instant I turn the filter on the PSI jumps back to 18 psi (normal is 10psi). I even went out and bought a new cartridge and after only 1 hour the PSI jumped from 10 to 18 and got the same results after soaking the new filter in the above mentioned baths. I now have 2 filters (the first was only 1 year old) that are utterly useless. I am soaking one in a copper algaecide bath to see if that has any effect. The cartridges are so bad that I have decided to run the filter with no cartridge at all but use a filter saver on the skimmer basket (panty hose type netting), which i have to take off and clean about every 20-30 minutes.