Hi Sherra;

You should only expect your 'numbers' to be stable, when your pool chemistry is.

When you are in the midst of a major treatment process, for whatever reason, it's normal to see fluctuations.

Being able to independently measure 5 parameters of your pool's chemistry (chlorine, pH, total alkalinity, calcium hardness, and cyanuric acid) tends to create the mental illusion that these are 5 *independent* parameters. But, they are not. What you do to affect one thing, almost always affects another as well. This fact is one reason why I emphasize avoiding unnecessary chemicals: they complicate things beyond comprehension, and make it exceedingly difficult to understand what you need to do to your pool.

In reality, your chemistry readings appear to be quite stable to me. Your calcium is unchanging, as I'd expect unless you did something to either precipitate it (raise the pH a bunch) or add to it (use cal hypo). Your stabilizer can diminish when a biofilm is present, but that doesn't appear to happen. Your one low reading is likely either a simple reading error on a hard to read test, or else a sampling error, such as taking a sample from the zone where you were refilling the pool after backwashing. Alkalinity is HIGHLY affected by small changes in pH . . . and your pH did change some. Plus, it can be affected by large quantities of bleach . . . and it appears that you added large quanties (as you should have done).

But, the reality is that over-testing can provoke over-treatment! I wish I could come up with simple -- but accurate --rules to say just when, and how much to test, but I haven't been able to do so.

What I'd encourage you to do is kill and clean up the algae completely, before worrying too much about the other stuff!

Ben "PoolDoc"