White gritty scale

[PoolDoc]

FC=5.72 ppm??

Must be going to a BioGuard dealer. There are no consumer or commercial grade mechanism for detecting chlorine levels to 0.01 ppm, but BioGuard is notorious for terribly erratic and often very inaccurate test results that their 'program' presents as super-accurate.

What that list of numbers tells me is, we have NO idea what's in your pool. That sort of computerized bogus testing is sometimes reasonably accurate (5.72 actually should be 4 or 4.0) and sometimes completely bogus (CYA = 0 or 50, instead of 14). We have no way to know, till you test with a reliable test kit.

By the way, you can probably confirm the identity of your scale, by scraping off a bit, and putting in in a clear glass (a wine glass would be perfect) with a bit of white vinegar. If it bubbles, it's calcium carbonate scale. If it does NOT bubble, cover the glass with Saran wrap, and wait till tomorrow. If the scale bits have dissolved . . . .it's calcium carbonate (limestone) scale.

OK, we can't do ANYTHING till we know what's in your pool. Do NOT use the chemicals you were given. (Don't take them back, yet, either. You may need them.) Instead, do this:

1. Get an OTO(yellow drops)/phenol red testkit. If possible, get the excellent Taylor-made HTH 6-way drops kit sold at some Walmarts (and nowhere else!). Check local availability here: HTH 6-Way Test Kit .

2. While at Walmart get 10 gallons of PLAIN 6% household bleach. Add 2 gallons of bleach this evening, and then each subsequent reading if your OTO test shows less than a strong yellow result the following evening.

3. Measure your pool. 16' x 48' is a VERY unusual size. On Google Maps it looks like maybe an 18x36 with steps. Measure only the main rectangle; do not include the steps. We can use those measurements to get a reasonable estimate of the gallons in your pool. (Most builders and pool stores over-estimate gallons.)

4. Read the test kit page in my signature, and then order a Taylor K-2006. You'll need it.

5. Report your test readings tomorrow. If you can find the HTH kit, report chlorine, pH, alkalinity, calcium and stabilizer. Otherwise, just report pH and chlorine.

6. Use these links to log in your pool info:

Pool Chart Entry Form
Pool Chart Results

By the way, the scale you describe is often deposited by algal & bacterial slime over the winter. Here are a couple of pictures:
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