Moblaine's pool

[moblaine]

At 7 p.m. tonight, I added 4 gallons of 12.5%. One hour later I tested using the Taylor K-2006 and got FC of 7.5 and CC of 2.0. Was a bit surprised that FC was only 7.5. Will test again around 7 a.m. and see what has changed. Any thoughts about the pool store liquid only bringing me up to 7.5 FC?

[PoolDoc]

Just looked for your pool chart entry, and didn't see it. If you would, please complete our new Pool Chart form -- it takes about 30 seconds, but will save much more than that. This is not the same as the chemistry log.

Pool Chart Entry Form
Pool Chart Results

However, based on a 4 gal dose of 12% bleach, you'd expect about 18 ppm FC. The fact that you are showing 7.5 could mean:

• You have ammonia in the pool which can be VERY rapidly oxidized by chlorine, consuming a lot of chlorine in the process, OR
• You have old bleach, or bleach that was stored hot, and is now only about 5% bleach (quite common!), OR
• Your pool store has fresh bleach, but is diluting it. (Very easy to do, if they have their own bleach tank.)

[moblaine]

I filled out the chart right before I did my post. It was a complete set of testing as or mid-day. For the evening test one hour after putting in 4 gallons 12.5%, I only did FC and CC so didn't enter it. Should I have?

[PoolDoc]

There are two charts; one that's a 1-time record of what your pool is like, equipment, dimensions and so forth. The other is a continuous record of your pool test results. You've done the pool test chart; not the pool equipment record.

[moblaine]

Gotcha. Chart is now filled in.
Just did my "within 2 hours of sunrise" test. Results were 1.0 FC and 0.5 CC. I liked your advice from the other day about maybe not worrying about CC any more and it has been low, around 0.5 or 1.0 ppm. But clearly something adverse is going on if FC fell from 7.5 to 1.0 ppm during the 12 overnight hours. My #1 concern at this point is to maintain sufficient FC to avoid algae. In prior years when I ran my Frog in-line feeder all the way open, I would have had higher FC readings than I do now (seems to hover between 0.4 to 1.0 ppm and only goes higher if I pour in 12.5% LC or 6% bleach). My fear is that without pouring in additional liquids, I am not maintaining a high enough FC level and not sure what I can do about that without resorting to nightly shocking. Driving my family crazy with this!

[moblaine]

Just wanted to update with good news. I did another 4 gallons of 12.5% liquid chlorine the other night and tested one hour later. Finally, I got a high chlorine reading (like 22 ppm). Within an hour of sunrise the next morning, I hadn't lost any FC. That was 3 days ago and I continue to get a chlorine reading so am very excited (today's FC is 3.5 ppm and CC is 0.5 ppm). It seems like I finally broke through and got rid of whatever was keeping me from keeping chlorine in the pool. Altogether, it took over 44 gallons of 12.5% LC this spring but the pool looks great, we're all swimming and life is good. Thanks for all the advice.

[PoolDoc]

Thanks for the update.

44 gallons of 12.5% -- that's about 160 ppm of chlorine in your pool, or more. Actually, you were on the list to contact. You reported 25K gallons, but also reported that you had a 16x32 IG pool, with a 3' shallow end and a 8' deep end. If those measurements are correct, your actual pool volume is either approximately 15,500 gallons OR 17,700 gallons, depending on whether the 3' & 8' measurements were POOL depth (deck to floor) or water depth. So, you may have added as much as 340 ppm FC!!!

Let's hope this winter doesn't reproduce the conditions that produced so many cases of ammonia-pooping bacteria this past winter.