How long should it take to clear black algae

[joecus]

Watermom - Great article. I did have a high CYA last year 100+. I did 3 partial drain and refills to get it down to current levels of about 70.

As far as my CC levels, I am taking 30 part tap water to 1 part pool water. I come up with a range of .5 to 2 on the scale of both my test kits. I then multiply by 31. Last night, I put cl levels up to 60+ this morning it was about 40. I am going to test right now.

I'm pretty sure my black spots are algae. Two weeks ago, I had trouble brushing them away (would not move). Now, it appears to be dead and are easily brushed off. The are mostly on the corners, and around my underwater pool light. It seams to like to form there but it does also sometimes form on bottom. I haven't touched it with my hand recently, but a few weeks ago it did not feel slimy to the touch and would not scrub off easily. Like I said, the pool is very clear, rarely used, 0 times since last Wednesday. Next week school is out and it will get much more use. Thanks, I will post complete set of numbers in an hour.

[PoolDoc]

It's not gone. Once you have black algae, it's rarely gone, unless you've drained, pressure washed, and resurfaced. It gets in, and under the plaster (see picture series below). You can kill the bits that are exposed, but not the bits that aren't.

You have to maintain levels of chlorine that prohibit further growth, because it tends to re-emerge the first time you give it a chance.



3/4" glass tiles to the right.


3/4" glass tiles above

[joecus]

Hello all, sorry it took so long to post. Here's where the pool is;
Last night my cl was 70 ppm.
cc = 70 ppm
This morning its 30 ppm.
ph = steady at 7.6
cya = 30-50 on aquacheck strips. I ran out of the cya testing drops - r0013.
The CL has not been under 20 in 5 days.

Pooldoc - my pool is an in 12,000 gallon, in ground liner pool. I assume this algae can be defeated, can it?
Watermom - I've been using less bleach the last few days 6-8 gallons. I've been going real high at night, 60-70. Checking it 4 times a day. I'm not sure if the reduction in bleach needed is due to my pool getting better or just the weather (it's been very cloudy the last few days). Please let me know what you think. Also, can anyone advise me where to best place is to get refills for the Taylor kit? What is the normal amount of cl burned during a sunny day? Thank you very much for your help.

[PoolDoc]

Controlled, not defeated.

Think of it as "cancer", and that with proper treatment (adequate chlorine levels ALL the time) you can keep your pool in remission.

Ben

PS. The only reliable way I know of "defeating it" means a new surface -- either plaster or epoxy paint.

[joecus]

Pooldoc - I'm not sure if you caught that I have a liner pool. Does that change anything? Any idea of how much bleach I should use on a normal day (no algae).

[Watermom]

Joe,
Ben probably did miss that part. He's out of pocket for a bit, so it may be a couple of days before he is able to get back to this thread.

A couple of questions for you? What kind of kit are you using? You cannot use the dilution method for extended periods of time, especially when you are going to really high levels like you seem to be doing.

I'm concerned what you may be doing to your liner with these kinds of high chlorine levels. Are we sure it is black algae?

Check that and maintain your chlorine levels for now until Ben is able to get back to you on this thread.

The way Ben suggests to check to see if it really is black algae is to scrape some off, and under your fingernail. Then, dry off, and smear the stuff under your fingernail onto a white index card. If the smear is green -- you have 'black' algae. Maybe you can try that to verify if it is indeed black algae.

I think we may have suggested it before up in this thread (don't have time right now to reread the entire thread) but in case we didn't, you need to get a good kit! (Amazon link below.)

[PoolDoc]

-- Momentarily camping out in the cabin owner's office --

I did miss the liner bit; if it is black algae, you can eradicate it from a liner pool. But . . . you must get all of it, and you should try the "shmear' test Watermom described to verify that that's what you actually have. In liner pools, plasticizer bleeding can look like black algae, but algaecides won't help at all.

Ben

[aylad]

Also, can anyone advise me where to best place is to get refills for the Taylor kit?

I get mine from spspoolspas.com. They can also be ordered from Amato industries online, or the taylortechnologies.com

Janet