Black Algae - SLAM / FC / CYA Levels

[rkyee]

Hi! I've been dealing with black algae for some time in my pool. I finally got the Taylor-Kit to do some formal testing, to try SLAM, and ultimately attempt to get rid of the black algae altogether. I did some testing, and need some help as the SLAM page has recommendations to start, so here are some details from my most recent testing:

- DE Filter
- CYA = 100
- Free Chlorine PPM = 8.6
- Combined Chlorine PPM = 0 (the color did not change back to pink when testing)
- Pool Water Clarity is very clear, not cloudy
- Based on the CYA/SLAM Level calculator, by Slam Level should be 39.
- I've been using Chlorine tabs to 'rub' the black algae over the past week, and have seen a significant decrease in coloration of the spores, but was hoping to increase chlorine to decrease more and more

Here are my questions:
1) The SLAM instructions suggest getting CYA Level to around 30, as the higher CYA will effectively eat away at the chlorine faster. What are suggestions to lower my CYA? Are there chemicals, or other mechanisms to help lower this overall?
2) Are there other tests that should be run in the Taylor K-2006 kit that would be beneficial? I only did the FAS-DPD and CYA tests, but can also run pH, TA, and CH (if they would be helpful).
3) Any other suggestions as it relates to attacking black algae in my pool?

Thank you very much in advance for the help and support.

 

[mgtfp]

It's not that CYA eats away chlorine faster, but most part of the chlorine binds to CYA where it is protected from UV. But it also does bugger all in terms of sanitation. That's why you need to follow the FC/CYA Levels to ensure enough "active" chlorine for the respective CYA.

You should run the CYA test with a diluted sample to ensure that it's not actually higher than 100, as described here:

Water Testing Instructions - Further Reading

www.troublefreepool.com

Drain/refill is the only way to reliably reduce CYA. There are some chemical/biological treatments, but they don't seem to really work.

 

[Mdragger88]

Cya doesn’t eat your chlorine- it binds part of the chlorine.
the higher the cya level the higher the necessary fc levels for maintenance & the
SLAM Process

This gets expensive & tedious with liquid chlorine being $5+ a gallon as the slam process can take days or weeks depending upon the starting situation.
Slam is still doable with a cya of 50 or 60 its just cheaper & simpler with a cya of 30 or 40.
The only way to lower cya is to exchange water with fresh.
If you’re measuring a cya above 90 you need to do the diluted cya test to be sure of where you stand so you exchange the correct amount of water
Step 8

CYA - Cyanuric Acid Test

Cyanuric Acid (CYA) is the chemical name for what is commonly referred to as Stabilizer … Read more…

www.troublefreepool.com

You should definitely do the ch test so you can be sure you remedy any high ch problem you may have with the water exchange as well.

Aside from getting cya under control & doing the slam process-
here’s some info on black algae

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.google.com

 

[rkyee]

I appreciate all the feedback and advice - I had some success with lowering the black algae, but not completely eliminated. I have some hope left!! Here are my current readings, taken as of yesterday:

• FC: 6.6
• pH: 7.4
• TA: 90
• CH: 850
• CYA: 100+ (not able to get an accurate measurement cause it was too high)

My biggest challenge is the CYA being so high that the FC is really not retaining. Thus, a couple of questions:

1. Is there a recommended method (that is cost effective) to remove water from the pool? I could backwash but that would only get far enough to the skimmer water line. I was thinking I could repeat this process but not sure if that defeats the purpose if its just running the same water in and out.
2. I've read on other posts regarding black algae to use a pump sprayer with undiluted LC. I have stupid questions incoming... is this like a regular pump like spraying bug spray? Can you also advise what undiluted LC is? Is this a recommended approach?

As always, appreciate the help and guidance!!

 

[Mdragger88]

I appreciate all the feedback and advice - I had some success with lowering the black algae, but not completely eliminated. I have some hope left!! Here are my current readings, taken as of yesterday:

• FC: 6.6
• pH: 7.4
• TA: 90
• CH: 850
• CYA: 100+ (not able to get an accurate measurement cause it was too high)

With your cya so high you likely won’t have much success so reducing that is priority #1

My biggest challenge is the CYA being so high that the FC is really not retaining. Thus, a couple of questions:

1. Is there a recommended method (that is cost effective) to remove water from the pool? I could backwash but that would only get far enough to the skimmer water line. I was thinking I could repeat this process but not sure if that defeats the purpose if its just running the same water in and out.

We recommend using a submersible pump so that you don’t risk running your expensive pool pump dry.
You can buy them at places like harbor freight or rent more powerful ones at Home Depot/lowes.
The no drain water exchange is the safest option especially if you’re unsure of your water table.
Read

Draining - Further Reading

www.google.com

1. I've read on other posts regarding black algae to use a pump sprayer with undiluted LC. I have stupid questions incoming... is this like a regular pump like spraying bug spray?

Yes, like this

1. Can you also advise what undiluted LC is? Is this a recommended approach?

Undiluted liquid chlorine- aka - bleach/sodium hypochlorite full strength.

As always, appreciate the help and guidance!!

 

[rkyee]

Thank you again!

We recommend using a submersible pump so that you don’t risk running your expensive pool pump dry.

Just purchased a submersible pump so will try this soon, and read through the Draining page as well.

ndiluted liquid chlorine- aka - bleach/sodium hypochlorite full strength.

Is there a specific brand/type that is recommended? I'd rather get one that is trusted, or known - so I don't get the wrong product.

I believe unrelated - but I am also having issues with my Zodiac Mx6 Vacuum Cleaner that keeps going "sideways" or on its back, so its get stuck in the same location. It will eventually find its way out, but more often than not, it is stuck in the same location cause it is "top heavy". Any thoughts to this?

 

[Katodude]

Is there a specific brand/type that is recommended? I'd rather get one that is trusted, or known - so I don't get the wrong product.

Nope, 10% from Walmart is fine. Any 10% one is fine.

 

[Katodude]

Also before you spray those spots you need to disrupt the film on the BA.

If you have a lot, I would use a weak pressure washer. Then get in with the pump sprayer and spray those spots.

 

[Mdragger88]

How to Chlorinate Your Pool

Before chlorinating your pool, you should know these simple tips. Learn the best way to add chlorine to your pool.

www.troublefreepool.com

 

[rkyee]

I believe unrelated - but I am also having issues with my Zodiac Mx6 Vacuum Cleaner that keeps going "sideways" or on its back, so its get stuck in the same location. It will eventually find its way out, but more often than not, it is stuck in the same location cause it is "top heavy". Any thoughts to this?

 

[Mdragger88]

I believe unrelated - but I am also having issues with my Zodiac Mx6 Vacuum Cleaner that keeps going "sideways" or on its back, so its get stuck in the same location. It will eventually find its way out, but more often than not, it is stuck in the same location cause it is "top heavy". Any thoughts to this?

Don’t have one but there have been a few posts on them - maybe you’ll find something helpful

Google search results

www.troublefreepool.com