Cleaning up algae and water mold in a Intex AG pool after vacation

My pool did OK last year, even with the pump going out in July and having to fight an algae bloom after the two weeks it took to get a replacement. The SWCG got the water clear after about 4 days of running just about constantly.

This year, I ran across this site and started applying the principals here, testing more often and using borax and bleach to augment the saltwater generator and get my numbers right, and the pool snapped into summer shape quick and has been much less of a hassle, with sparkling clear water.

We went out of town for a week and when we got back I found the pump had tripped its GFCI (probably a power surge, not uncommon during T-storms or hot Texas summers here), so I don't know how long the pool sat unfiltered. The water was a little cloudy, but no visible algae, and I figured it would be no big deal to get it back in line.

Here are the numbers I found:

Free Cl = 0.4
Combined Cl = 1.4
Total Cl (OTO) = 2.0
pH = 7.4
Alkalinity = 90
Cya = < 30 (no reading)
NaCl = 2600

So I added 2 pints of bleach and ran the pump and SWCG (8 hrs pump, 7 hrs SWCG) and checked the following morning, finding the numbers virtually unchanged. The combined Cl really concerned me, because I thought the SWCG would break that down, even if the free Cl wasn't keeping up with demand. So I nuked the pool with an entire bottle of bleach (121 oz of 8.25% hypochlorite), cleaned the SWCG cell with diluted (1:5) muriatic acid, put 20 oz of Cya in a sock in the skimmer, and ran the pump/SWCG for another 8/7 cycle overnight, and the numbers were still virtually unchanged the next morning.

The water is a little clearer, but I really thought all the bleach I added would jack the Cl way up to shock levels, and also I'm still puzzled why the SWCG (which appears to be working fine, producing bubbles at the plates) isn't breaking down the combined Cl.

OK, important addition, I'm pretty sure the cloudiness is white water mold. I noticed tissue-paper-looking things in the water, although it appears they are diminishing/being filtered out. Would this explain the low free/high combined Cl? Should I just dump a couple of more bottles of bleach in and keep filtering/SWCGenerating?

1. Next time you go on vacation, buy polyquat, lower your chlorine to 3 ppm or below, remove your cartridge filters (or put the filter on recirculate), and add a double dose of polyquat (www.poolsolutions.com/polyquat.html)
a) This is Intex specific advice.
b) Polyquat is removed, gradually, by the filter. Taking the cartridge out prevents that.
c) High chlorine breaks polyquat down.

3. But, this time, turn the SWCG off for now, AND

4. Start adding 1/2 gallon of PLAIN Walmart (or other 8.25% bleach) EACH evening.

5. Skip a dose, if the OTO chlorine level is orange or orange-ish yellow. (Yellow / red test drops, bought locally)

6. Remove the cartridges and carefully follow the cartridge cleaning guide: Cleaning-your-Cartridge-Filter-wiithout-Damaging-It!

7. After you are done, soak the cartridge in 1/2 gallon bleach + 2 1/2 gallons of water.

8. Keep treating the water with bleach for ONE WEEK after all traces of the water mold are gone.

9. Get some stabilizer in there (use dichlor?) and do NOT let your chlorine drop below Best Guess minimums for the rest of the summer (See Best Guess page link in my signature.)

10. Do NOT worry about CC levels, etc. until you've completed steps above. Most likely, CCs will no longer be an issue once you have finished.

Thanks for the advice. Curious: why turn off the SWCG?

SWCGs typically only produce enough chlorine for *normal* water with no problems; running them when you have problems just shortens their life. Since you STILL will have to add chlorine by hand, it's better to add ALL the chlorine you need, and save the SWCG for when things are normal.

As it is, most people find that their SWCG cells have to be replaced much sooner than they expected.

Ah -- OK. I already replaced one, but it was the control board, not the cell. It's a project in my garage. ;-)

Oh, yes. Those projects you're gonna get done when you get around to it. I've got some of those. But I still haven't gotten the projects done.

However, I do have a nice round tuit:
https://lh5.googleusercontent.com/-L...d-tuit-web.jpg

PoolDoc, thanks for the tip -- after three days the Cl snapped back and the water's crystal clear again.

New numbers:

Free Cl = 5.8
Combined Cl = 0.2
Total Cl (OTO) = 3.0
pH = 7.4
Alkalinity = 120
Cya = 70 +
NaCl = 3000

(The pH dropped to 7.0 when I added cyanuric acid and I bumped it back up with borax)

I'll keep adding bleach for a week like you suggested so I don't have a recurrence (just added an extra pint this morning because I expect a heavy swimmer load for the 4th).

Strat,
Use a 10mL sample when you test instead of a 25mL one. It will make your testing reagents last longer.