total chlorine vs free chlorine

[magnus]

Will review the "bucket test" and do it. CYA is same as "stabilizer", right? Mine was 33....which looks to be low but still within "normal" range? I don't have a Ca++ category on the water test....but Total Hardness is 163 (normal 175-225 acc to sheet). Aren't they related?

Thanks for the help.

[PoolDoc]

CYA = cyanuric acid = stabilizer

33 ppm is OK, but low in most cases. However, I don't trust the reading -- the actual accuracy of test strip reading for CYA is +/-30 ppm OR worse! Your actual CYA might be anything from 0 ppm to 60 ppm!

Total hardness = Ca + Mg => but on most pools, it's 90+% Ca (Ca = calcium; Mg = magnesium). And, Mg doesn't cloud the water when you add soda ash!

BTW, your bucket test results for chlorine demand won't be too accurate, till you have the K2006. There are work-arounds, but they are tricky.

[magnus]

Here's my concern.....the bucket test looks like it takes a couple of days to fully complete. I can start on that tomorrow after getting the ingredients. BUT....I don't want a green pool, since I've shut down the chlorinator (per advice of the pool store guy). In an effort to head off an algae bloom, would you recommend that I kick the chlorinator back on high and then add some amount of Bleach??.....in an effort to get a registered amount of Free Chlorine. Any guide on how much bleach?

[magnus]

In reading around.....I've read several recommendations for "non-chlorine shock" in order to oxidize and free-up the bound chlorine....and break the "chlorine lock" that I apparently have. Any thoughts on this?

[chem geek]

I don't think that will help and it will be a lot more expensive than chlorinating liquid or bleach. You need to shock your pool with chlorine and keep adding it until you start registering an FC level. You may have a lot of ammonia in your pool, though normally that comes from a breakdown of CYA by bacteria. Did you just open your pool and find this problem? If so, then that may be what happened, though all the CYA didn't get converted since you still measure some.

[PoolDoc]

=> The chlorine demand bucket test doesn't take a couple of days. A matter of hours should be enough. It *will* require a K2006 or equiv for meaningful results.

=> If you raise the pH above 7.6, and continue to maintain high levels of CC, the CC will gradually take the form of monochloramine, which is a very effective algicide. But, you don't want to swim in 7.5 ppm of monochloramine -- it will severely irritate your eyes, and possibly, your skin.