Opening pool with massive algea growth

I have opened our pool and it had a lot of algea growing it in. The pool is 27,000gals vinyl. I added an initial dose of 20 gals of 12.5% Liq chlorine which figures out to roughly 90 PPM and this AM I tested with the OTO test kit and a zero reading of cholrine (clear no color at all) So we put in another 12 gals which should be roughly 54 PPM and again I have a zero reading on the OTO test kit. (clear no color at all). I have never put in this much chlorine before and I just wanted to make sure that there is no way I have put in too much chlorine that its fooled the OTO test kit.

Do you know what the CYA reading was when you closed it last fall and have you checked the CYA this year? Many times over winter, you have bio-degradation of CYA into ammonia and it can take massive amounts of chlorine to get rid of it. I can't imagine that after that mega-dose that you had none this morning though. Do you have a it that can measure a CC (combined chlorine) reading?

If you don't have a good kit, you should get one. The one we recommend is the Taylor K-2006 or 2006C which you can get through the test kit link in my signature below. You're gonna need it because most kits can't read chlorine levels as high as you'll need to clean this up.

Welcome back to the Pool Forum!

I had a CYA reading of 20-30 last fall at closing. Typically when I open up in the spring the CYA is 0 so I am assuming that is the case this year as well. I have the DPD powder test kit that was sold with the test you kit you used to sell via this site. But I have read where it can't test above 15 PPM so I haven't done that test yet. If I have CC what do I need to know.

The FAS-DPD testing that was sold with Ben's kit will test chlorine up to 50+ ppm. If you're using OTO, then it probably is bleaching out. I can't imagine that much chlorine in one pool being used up that quickly, even with a big chlorine demand due to ammonia that is often produced when CYA is degraded over the winter, like Watermom said in her above post. Go ahead and run your test with the powder and drops--that one is WAY more capable of testing high chlorine levels than any of the others.

If you have high CC, that's another indication that your CYA was degraded into ammonia and will help us better figure out how to advise you.

If you are still using the DPD-FAS powder from one of Ben's old kits, it probably is no longer any good. You might want to order some fresh powder.

Okay, I've gotten new test kits and here are my results as of today. Total Cholorine 14 ppm Combined Chorline .5PPM PH 7.4 CYA is 0 Pool has a greenish haze. have been operating the filter (its a sand filter) 24/7, have vacumed the dirt off of the bottom and brushed the sides. I read somewhere where that it wasn't recommended to run the water through the filter when there is a lot of algae but we did. Do I turn the filter off for a day or two and keep the chorline high and let the stuff settled out? and then vacum up to waste?

Yes, you definitely need to keep the chlorine high--until the green is completely cleared up and you are not losing any chlorine overnight (testing at night and again in the morning before the sun hits the pool). If you see the pressure on your filter rising, indicating that it's catching the algae going through it, then I would leave the filter running and let it do its job. If you see anything blowing back through the returns, or your filter pressure isn't rising, then I would consider turning the pump off, letting it settle, then vac to waste.

Here are some test results from the last two days.

Evening day 1 TC 15 (didn't test CC but its been consistently at 1 ppm through this whole ordeal)
Morning day 2 TC 12.5 CC 1.0 Loss 2.5PPM during the evening.
Day 2 before adding the nightly dose; TC 5.5 CC 1.0 Loss 7 ppm throughout the day
Added 3 gals of 12.5% pool chorline
Evening Day 2 TC 23.5 CC 1.5
Morning Day 3 TC 17.5 CC 1.0 Loss 6 ppm overnight. (also had rainstorm and picked up 2" of rain during the night as well)

Pool is an in ground vinyl lined with 27,000 gals
Brushed pool last two nights and I can see a lot of debris get stirred up each time (especially in the deeper end )

Any other suggestions as to what I should be doing.

Quote:

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Originally Posted by aylad

If you're using OTO, then it probably is bleaching out.

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Just FYI. OTO doesn't bleach out and can be used to test very high chlorine levels as it goes from yellow to orange to red. It may not be very accurate and there are no comparators showing the high FC level colors, but it will tell you whether you have a lot of chlorine in the water.

It is DPD that will bleach out. Even the DPD in the FAS-DPD test can bleach out, but you get a "flash of pink" when adding the DPD powder in that case so can just add more until the color holds at which point you titrate with FAS-DPD drops normally.

You might try vacuuming to waste since you have a lot of debris and you picked up a few inches of water with the rain. The less organic stuff in there, the faster it will clear up.