Algae that won't go away! 32 gallons liquid chlorine so far

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D

dmdrums

0
Jun 10, 2008
25
Hello-

I have a 15,000 gallon pebbletec playpool that gets FULL sun from nearly sunrise to sunset (no trees, no shade from anything).

Here in AZ, we had a huge dust storm almost a month ago that left the pool quite a mess. I thought it was all cleaned up, but I saw some brownish "stains" on the bottom. One was approx. 18" circle, one 12" circle, several other smaller circles. Silver dollar sized spots on the large swim step. When I brushed, I could see moderate algae but the "stains" did NOT come off at all.

I didn't take a photo of the algae, but it was HIGHLY aggressive. I would brush and within an hour I would need to brush again. The stuff that did brush off was on the shaded walls and looked just like mustard (although I don't know enough to determine if it is actually mustard algae - and I tried looking at lots of photos).

My shock process started Saturday evening when I added 9 gallons of 10% liquid chlorine (should have created approx. 54 ppm - but the chlorine was 2 months old and despite the 74 degree storage temp, only generated approx. 27ppm). Super filtered, yeah right....had a bunch of solids on the bottom of the inside of the jugs.

My CYA is approx. 85 and I do have the TF-100 kit.

Here are my actual chlorine results.....

7/30 (Sat sunset initial test) 1 ppm Add 9 gal 10% older chlorine
7/30 (Sat at sunset) 27ppm
7/31 (Sun AM) 20.5 Add 5 gal older 10% (approx. half strength)
7/31 (Sun PM) 32 ppm
8/1 (Mon AM) 28 ppm
8/1 (Mon PM) 23.5 ppm Add 2 gal 10% NEW stronger chlorine
8/1 (Mon Late PM retest before bed - 1 hr after adding chlorine) 32ppm
8/2 (Tue Early AM - before sunrise) 30ppm (only lost 2 ppm overnight in 7 hrs) Add 3 gal 10% older chlorine (yes, had a lot left over)
8/2 (Tue Late before bed) 22 ppm

The problem:
I have been brushing the pool 3-4 times per day and now the water looks milky when brushing (I think that is dead algae). However, I can brush 30 minutes later and it appears to be just as much algae on the bottom, like it keeps returning.

I couldn't find my vac, so I threw in the Polaris (didn't want to with 22ppm chlorine and had it out for shocking). Backwashed 3 times tonight (sand filter), each time looking white for 20-40 seconds.

I don't want to throw in more chlorine and trash the Polaris, but I'm not sure if i'm done fighting the algae (I don't want to do this again!).

Without the Polaris, I don't see the white cloud of algae on the bottom ever leaving.

Pool looks really good, until you brush it!

Filter runs 17 hours a day on high (off from noon to 7pm during peak power pricing). Water temp approx. 92 degrees - HOT!

Read the whole pool school and it says this might continue 2 weeks and that when ppm drops only 1 overnight you are good. Mine was 2 last night, but my residual chlorine is still 22, so I'm guessing it will fight tonight still.

Should I do anything special, or just keep brushing and let the chlorine fall back to 5ppm?

SWG is being installed in the next week or two....I can't handle doing this again!

Thanks!!

Dalton
 
Re: Algae that won't go away! 32 gallons liquid chlorine so

With a CYA of 85, shock level for you would be a FC of 33. So, unless you are at 33 ppm on your FC, you technically aren't shocking and this may be the reason that you have had to wage this battle for so long. Bad algae infestations take time, brushing, filter time, and discipline in keeping your FC at or above shock level or in your case, 33 ppm.

If you are losing 2 ppm of FC overnight, you still aren't finished. What you should do is raise your FC to 33 at least and keep it there until your FC loss overnight is 1 ppm or less, your CC is 0.5 ppm or less, and your water clears up. During this process, run the pump and brush as much as you can.
 
Re: Algae that won't go away! 32 gallons liquid chlorine so

I just finished shocking my pool and it took eight days and 64 gallons of chlorine. Even after the over night chlorine loss was zero it took several more days before the pool cleared up. I ran the pump 24/7 and the polaris about 2 or 3 hours per day. There was a lot of the white stuff (I assume dead algae) that would cloud the water every time the polaris ran. If I brushed the bottom the fine white particles would look like smoke rising. Patches of dirty brown looking debris (I assume more dead algae) would collect in the quiet areas. For awhile it looked like I was doing more harm than good and considered draining the pool and starting over.

Now the pool looks really good, but it was a hassle getting it that way. So just hang in there and keep the chlorine level up.
 
Re: Algae that won't go away! 32 gallons liquid chlorine so

Thank you both for your replies!

I went to the pool store and bought 24 more gallons of new 10% chlorine.

I also added more chlorine this morning and now have 39 ppm.

Despite being less than 20 ppm this morning, I can see less milky stuff while brushing, so I can finally see some progress.

I am going to run an overnight ppm test tomorrow night, since I am running low on testing supplies now and am not sure if anyone local would sell more of the drops for the high limit chlorine test. I have plenty of the powder, but I'm going through TONS of the drops!

Have a great day,

Dalton
 
Re: Algae that won't go away! 32 gallons liquid chlorine so

You could try using a 5 mL sample, and then each drop counts as 1 ppm so you use half as much. There's a substantial loss in accuracy, but it should still be adequate for maintaining shock level (though not the OCLT, for which you should still use the standard 10 mL sample). Just keep in mind that your results might be 20% off and target a slightly higher FC accordingly.
 
Re: Algae that won't go away! 32 gallons liquid chlorine so

Keep up the hard work! You're in the right place. There have been several threads since that dust storm. I imagine the pool stores there are bilking the masses for tons. It's costing you a lot but at least you are doing the right thing.

I'd go to a Lowes or Home Depot and ask for a volume discount on liquid chlorine. They are the cheapest in my area of CA anyway.
 
Re: Algae that won't go away! 32 gallons liquid chlorine so

Not a bad idea!

I was getting the 2 gallon 10% packs for $3.88 at NPS pool store (it was on sale).

It just changed to $6.88, but they honored my coupon, so I bought 6 cases (2 gal/case) for 3.88 and 6 cases at 6.88.

Not sure what Lowes charges and what % chlorine they sell, but I'll have to check.

Thanks,

Dalton
 
Re: Algae that won't go away! 32 gallons liquid chlorine so

Cool! Thanks for your reply. I have a few of the 10% off coupons that I can use, so when I am ready for more I will head to Lowes instead. They are open later too, so it would be easier to go there besides.

Have a great evening,

Dalton
 
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