Hi, I found this site a couple weeks ago after opening our pool to find a swamp. After reading Pool School, I've become much more educated on pool water chemistry and have started with the BBB approach. Everything is now working well (except the weather). We've had the pool since 2002 and this 'swamp' problem has occurred every 2 or 3 years and my solution has always been to replace the water -- problem solved for the summer. However, last year our water company started metering our water usage and I'd prefer not to refill the pool with tap water if possible. I still have some questions -- the learning process continues, but the water has been sparkling clear for almost 3 weeks now.