Backwashing and shocking

[CarlD]

Sorry!

There is a learning curve on chlorine tests. There are 3 tests:
1) OTO. This is simple and reliable and comes in the cheap, $5-$10 test kits that test chlorine and pH. But it's got two limitations--the kits usually only measure to 3ppm and a FEW go to 5ppm--we frequently need measures up to 15 to 25ppm. Also it only measures Total Chlorine. The good thing about OTO is the color gets more and more intense with higher chlorine even if you cannot measure it.

2) DPD. This is a test capable of measuring chlorine levels up to about 10ppm--but the test kits rarely go above 5ppm. It can measure both Free Chlorine and Total Chlorine, allowing calculation of Combined Chloramines (which, if more than 0 means something's growing). But above a certain point, the chlorine BLEACHES the tests making them look like you have NO chlorine. For these reasons I don't like DPD.

3) FAS-DPD. This is the gold standard. You don't need to recognize shades of color--you add a powder to get a colored solution and then you add drops until it goes clear again. You can safely measure up to 50ppm of Free Chlorine and it also measures Combined Chloramines. (you get TC by adding Free Chlorine and Combined Chloramines). If you use FAS-DPD testing, you don't need to use any other chlorine tests.

Also there are strips, but to me, they only indicate if you have LOTS of chlorine or need to measure it with OTO, DPD, or FAS-DPD.

[jmcrae]

Thanks Polyvue and CarlD.

I appreciate the input. It rained tons last night (due to hurricane Alex) so I'm in the pool to vacuum and backwash. There's lots of stuff on the bottom but nothing on the sides yet. I'll check back in when I get the FAS kit and post the new levels. Meanwhile, I'll vacuum, backwash, bleach, vacuum, backwash, bleach, .....

[aylad]

Once the fallout from Alex is over with, I would definitely shock the pool--goodness only knows what kind of crud came with the rain from the gulf!!

Janet

[jmcrae]

I vacuumed this morning at 6:30 and put in 7 quarts of bleach. By 4:00 pm, the pool was full and I could see a layer of brown on the bottom. It's almost 7:00 pm, I've had to let more water out of the pool (so much for the bleach!), and it's still raining cats and dogs. I'm setting the alarm for 3:00 am ... thanks so much for all your encouragement everyone!

[jmcrae]

Hey, I'm back!
My pool hasn't beat me yet. Hurricane Alex almost did! We had constant rain in Katy... 26 miles west of Houston ... for two days. Needless to say, lilly-livered coward that I am, I did not venture into the pool for any length of time. I took advantage of breaks in the rain to vacuum when I could and every time I vacuumed I backwashed to waste (Alex was doing just great in replacing the water!) and I dumped a gallon of bleach morning and night.

Every time I looked at the pool after dumping the bleach, I had a visible layer of algae... but it decreased with each application. Yesterday evening I vacuumed just before sunset, poured another gallon of bleach and lo and behold, this morning I had negligible algae!!! I vacummed, dumped another gallon of bleach and raced to WalMart to get some distilled water. I did the 3-1 (OTO) ratio for the Chlorine: FC/15; TC/15; I did the regular DPD test for the rest: AK/140; pH/8.2; CYA/55.

The water is beautifully clear.

Did I do good?

[Watermom]

Yep. You done good! Tonight, test the cl at sundown and then early tomorrow morning and see if you lose more than 1ppm. If you do, shock it back up. Continue keeping high cl until you can hold it overnight. Also, retest your pH whenever your cl isn't high so you can get an accurate reading.

[jmcrae]

Will do.
Thanks to all for your wonderful assistance!