Persistent Grey “algae”

[Hatalss]

I am on day 11 if trying to rid a small (12x16 oval) above ground Simple Salt pool of a weird Grey is algae that cannot be scrubbed away or effectively killed( so far) with a myriad number of various chemicals.
The pool place has thrown in the towel on my case and I am left with an algae stained pool bottom. Water is perfectly clear. Any suggestions?

 

[tikoh]

The pool company throwing in the towel is likely a blessing in disguise. I would guess that most of those chemicals were unneeded. Do you have any photos of the situation you're dealing with?

The next step is to buy a reliable test kit that includes an FAS-DPD chlorine test. They can be found on tftestkits.com amongst other places. While you're waiting for the test kit to arrive, add enough liquid chlorine to add about 5ppm of chlorine to your pool per day. For your 7,000 gallon pool, that's about 1/2 a gallon of regular unscented bleach per day. You can buy it as bleach from target (just get unscented, regular bleach, not splashless), or in stronger concentrations from a hardware store or pool store. Once your kit arrives, post a full set of results here.

You can also read the pool school articles, starting with ABC's of Pool Water Chemistry

 

[Hatalss]

Thanks, I’ve attached photos taken this morning without sun. The shadowy areas are the grey algae. I was in, what the pool people called, a chlorine lock. However it seems I’ve recovered from that and now have active chlorine but still have algae.

 

[duraleigh]

Our advice begins and ends with accurate testing so we know where to start.

It sounds like you have been relying on the pool store for that and the results are obvious.

Perhaps you have calcium scale and perhaps some imbedded algae but hard to say without test results we trust.

Do you have your own good test kit to post those results?

 

[heikejohn]

This kind of looks like mine when I had metal staining.
Have you tried to rub some vitamin C tablet (Ascorbic Acid) on the stain?

 

[Hatalss]

Our advice begins and ends with accurate testing so we know where to start.

It sounds like you have been relying on the pool store for that and the results are obvious.

Perhaps you have calcium scale and perhaps some imbedded algae but hard to say without test results we trust.

Do you have your own good test kit to post those results?

I don’t have a test kit other than Simple Salt strips. I am more than willing to purchase what is needed but would like some suggestions if you would provide a recommendation, I would be grateful. Thank you

 

[Hatalss]

This kind of looks like mine when I had metal staining.
Have you tried to rub some vitamin C tablet (Ascorbic Acid) on the stain?

No but I’m certainly willing to give it a go.
Thank you

 

[tikoh]

I agree with the others that it could be metal staining..maybe calcium?

"chlorine lock" is a condition where your CYA is so high that it is difficult to maintain free chlorine high enough to provide effective sanitation. This occurs when your CYA reaches around 90-100 ppm and is common in pools that use trichlor pucks or dichlor powdered shock. CYA is what the pool store sells as stabilizer and is also a part of dichlor or trichlor products. At low levels it protects your chlorine from degradation by UV from sunlight. However, by binding to chlorine, it reduces the chlorine's effectiveness. The more CYA you have, the more free chlorine you need to effectively sanitize your pool. You can read more about it here Free Chlorine and Cyanuric Acid Relationship Explained

In the meantime, try to keep your FC high while you wait for your test kit.

 

[MITBeta]

if you would provide a recommendation, I would be grateful.

The TFP-Pro is a favorite around here. But see Test Kits Compared.

 

[tikoh]

So I just re-read this and then researched the simple salt pool system...I'm not sure that system is going to work with the TFP method.

I can almost guarantee that your staining is copper. The simple salt system introduces copper and silver into the water. When your chemistry is spot on, that's probably fine, but when it is not, it comes out of solution and you end up with the mess that you have.

 

[Hatalss]

Thank you for following up. My last visit to the pool place they suggested a stain remover. $36. Later I have a bottle of caustic granules that are to be sprinkled over the stain ( more than half the pool ) through a dock or stocking????
Thinking of just giving up and getting a new liner and new water. Very disheartening. Thanks for sharing your thoughts.

 

[tikoh]

Thank you for following up. My last visit to the pool place they suggested a stain remover. $36. Later I have a bottle of caustic granules that are to be sprinkled over the stain ( more than half the pool ) through a dock or stocking????
Thinking of just giving up and getting a new liner and new water. Very disheartening. Thanks for sharing your thoughts.

Even if you do that, you'll likely end up with the same problem if you stick with your copper system.

 

[dfwnoob]

Pick up a Taylor K-2006C or a TFTestKits.net TF-100/TF-Pro and lets get this thing tested properly. They both use the same reagents, but the TFTestKits models are a better deal.

It's not required, but a Taylor SpeedStir or TFTestKits SmartStir is strongly recommended.

 

[Hatalss]

Even if you do that, you'll likely end up with the same problem if you stick with your copper

Even if you do that, you'll likely end up with the same problem if you stick with your copper system.

Is it possible to remove the copper staining and convert to a traditional chlorine system. I had an in ground pool for 25 years and never experienced algae or cloudy water.

 

[tikoh]

Is it possible to remove the copper staining and convert to a traditional chlorine system. I had an in ground pool for 25 years and never experienced algae or cloudy water.

I don't see why not