Sorry this may be lengthy, first a little history/equipment . Just put in pool 4 months ago with so called reputable pool company. Pool is gunite/plaster about 12000 gal, Pentair VS pump, cartridge filter, and CMP PowerClean chlorinator. Now the issue, I first started off with a Rainbow Pentair chlorinator. After about 8 weeks I noticed none of the 5 tabs had dissolved (not even a little bit). Pool Co. came out to trouble shoot but ended up installing the current PowerClean chlorinator. It has a glass window so I can see what is going on inside. I put 2 tabs in it, removed the air and started the system. During the initial surge of the pump start, the water clearly enters the canister through the tall standpipe. This occurs for only a brief period. As the pump speed reduces to preset 2500 rpm, the flow from standpipe decreases to a barely noticeable trickle. As the day progresses, the water level in the canister slowly becomes less and less until it is dry (about 8 hours). The next morning when the pump kicks back on at 8am, a fairly decent stream of water enters the canister, again until the pump slows down to the 2500 rpm-- then back to a tiny trickle. I have to manually crack-open the canister lid to bleed out the air before a decent water stream from the standpipe is observable... However the process starts again, the canister slowly empties though out the day until it is dry. Another tidbit of information is, if I bleed the air out at the end of the day the canister will be empty by morning... this is without any equipment running. So far the trouble shooting by my pool expert has been: check for air leaks around equipment, ensure cartridge filters are clean, make sure there is no clogs in check valves or lines feeding chlorinator. He increased the operating flow of the pump to 2700 rpm which did not help at all. Now he is proposing to increase it another 200 rpms. It seems to me there is a problem somewhere in the system and his intent of speeding up the pump even more is putting a bandage on an underlying issue. I would sincerely appreciate advice!!!!