Can I start adding CYA if my chlorine level is 15?

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I have a black algae problem and so I raised the chlorine level to combat it. However I forgot to test the CYA level. When I did it seems to be 0 (not a test I have a lot of faith in). The CYA manufacturer recommends a chlorine level of 1-4 before beginning. Is that really necessary? If so I guess I'll have to get a chlorine lowering product. I hope to hear back soon as the black algae is going to town!

saltwater pool
CL 15
CC 1
pH 7.4
CH 270
TA 100
water clear

 

[Flying Tivo]

you need 30 ppm of cya

 

[ajw22]

You can add stabilizer with any chlorine level. You don’t need to lower chlorine.

Add 30 ppm of stabilizer using the sock method.

Recommended Pool Chemicals

Which should I buy? TFP's recommended pool chemicals are cheap, easy, and won't unbalance your pool water.

www.troublefreepool.com

Solid/granular cyanuric acid (CYA) should be placed in a sock and the sock put in the skimmer basket or suspended in front of a pool return. After adding CYA you should leave the pump running for 24 hours and not backwash/clean the filter for a week. Squeezing the sock periodically will help it to dissolve faster. Test and dose chemicals in your pool assuming the amount of CYA added is in the pool according to Poolmath. CYA can be tested the day after it is fully dissolved from the sock.

Black Algae

This guide provides a step by step procedure for eliminating black algae in your concrete or gunite pool. Read full post here.

www.troublefreepool.com

 

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Thank you all for your help!

 

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One other question. The guide I got from TFP for Saltwater pools is to have the CYA level be 70-80. You are recommending 30. Is that a starting point so I don't add too much?

 

[duraleigh]

Is that a starting point so I don't add too much?

No. 30 ppm is a reasonable level to perform the SLAM process and get your pool clear. 70 ppm or so comes after your SLAM is complete, the black algae gone, and you are in maintenance mode.

Black algae is often misdiagnosed.......do you have a pic?

 

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Don't know how to add a picture,but I tried. We have had black algae before when our pool was plastered. Now it is tiled. Anyway. It's black and hard to scrub off and looks green when you scrub it.

 

[duraleigh]

Sure sounds like black algae, then. It will take not only the SLAM process but then some follow up with a wire brush and elevated chlorine if you wish to get rid of it.

 

[ping]

Have you seen the black algae write up in Pool School, Black Algae - Trouble Free Pool, follow these steps to get rid of it.

 

[Etchase]

I was thinking of tiling to permanently eradicate my black algae problem. Guess not. I was wondering if it came back just in the grout or on the tile too? Do you think it is a new outbreak or is it reoccurring in the same areas that it was a problem on the plaster. Tough problem.

 

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Thanks again. I am worried though about using a wire brush on tile. No one seems to consider tile when they talk about pool surfaces. On the pool calculator I use plaster as the closest choice. And I did read TFP's write up on black algae ( and several others) . That's my starting point.

 

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To Etchase. It is on both the tile and grout. But it was clear for a year. However I didn't keep up with the chemical balance and so I think it's mostly my own fault.

 

[Etchase]

Mine comes back in about a year too. I’m going to try using a pressure washer underwater next time. Have no idea if that will work, but it works well when the pool is empty. Good luck.

 

[ajw22]

Thanks again. I am worried though about using a wire brush on tile. No one seems to consider tile when they talk about pool surfaces. On the pool calculator I use plaster as the closest choice. And I did read TFP's write up on black algae ( and several others) . That's my starting point.

A tile pool is considered a plaster pool for water chemistry purposes.

 

[duraleigh]

I can also add that black algae typically occurs in pools with chronic low chlorine issues. You both can clear your pool once and for all if you are willing to practice the methodology TFP teaches. This is Royce's thread so, Etchase, if you have further questions, please start your own new thread and we'll all help get you both crystal clear.

 

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To Etchase But it comes off the tile easily. We will see about the grout

 

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Well the last little bit of black algae seems to be gone. How long should I keep the chlorine level elevated to be on the safe side? I think I have read 2-3 days. Do you agree?

 

[JJ_Tex]

Do you meet the 3 criteria to end the SLAM?

You are done when:

• CC is 0.5 or lower;
• You pass an Overnight Chlorine Loss Test
• And the water is clear.

The end of the Black Algae article also mentions to keep the chlorine high for a week after the water is clear to kill any remaining black algae.

 

[ping]

Keep the FC level at the high end of the normal range in the FC/CYA chart for about a week or so.