Low Chlorine


New member
Jul 23, 2007
Free Chlorine 0
ph 7.5
TA 90
CYA 50
Total Dissoloved Solids 1550
Phosphates 75

My water has been cloudy since the beginning of the season in May. We have pine trees close to our pool. I cannot keep chlorine in my pool. I recently had a bout with yellow algae which is visually cleared up after adding a strong algaecide. I followed up with 5 lbs of shock that had a stablizer and clarifier over the course of 2 days. Then my chlorine went back down by the next day. What are your thoughts on this? The pool company says to add 5 lbs of CYA.

Thanks so much.


In The Industry
Mar 29, 2007
Knippa, Texas
Assuming you DON'T have an SWG, DO NOT add any more CYA. The amount you have is good but a little on the high side. Are these numbers from your own tests or a pool store? What about CC's?

I'm not one of the experts on this board, but I have been hanging around a lot so I know a few things. Cloudy water can have any one or more of a number of causes. It could be dead algae, in which case you just need to filter it out. I believe it's Waterbear who's fond of saying a clarifier can clear your water in seven days while filtering may take a week.

In the absence of other information, I'd say keep your FC level up, say 15-20, with bleach and run your filter 24/7 for a couple of days. . .


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
A CYA level of 50 is just fine. Raising it will make fighting the algae much more difficult.

The key to beating algae once and for all, particuarly yellow algae, is to bring your free chlorine level up to shock level and hold it there for a day or two. This requires being able to acurately test high chlorine levels and being able to distinguish free chlorine from combined chlorine. You need test the FC level, add chlorine to bring it up to shock level, which is normally 15 (but could be as high as 30 for some kinds of algae) (at a CYA level of 50), and to repeat this process at least three times a day until your free chlorine level holds overnight and you don't have any more combined chlorine.