we double shocked the pool as told by the pool place and it lightened up from dark green to cloudy teal blue. we shocked again and used banish. we used clarifier because the pool was cloudy. we woke up this morning and it is turning green again. they are saying we dont have any chlorine in the pool but we filled the chlorinator and the skimmer. we are at a loss because we dont know what is going on. it stayed clear and beautiful all winter long and up to spring but now it will clear up and turn right back green. also the pressure is reading 20 to 25 could this be the problem? this all really started when we noticed the pressure was high. we were told that we may have a leak or air was getting in somehow. we have done everything that we know possible. we put new sand in back in april before we opened the pool. we have had to shock it a lot, but this time it wont come clear. please if anyone can it would be appreciatted. it was swamp green when we moved in last year and we finally got it clear in october. this is the first time we have dealt with a pool.