Need help-High Cya, calcium, and algae

[Turbo]

I assume acid washing is done with muriatic acid. What mixture do you use and what effect does this have on the bottom of the pool while washing?

Greg

[Turbo]

I drained the pool and it appears that the stains are not really stains. I think it is yellow algae that is growing in the crevices and round pocket holes you can't reach. Even so, I tried applying ascorbic acid and then scrubbing it to no avail. If anything, it bleached the area some from the natural white wall color (looks a little greyer to me).

I would then assume that once I get the pool full again with the correct ph, TA, CH, and CYA, I can keep the chlorine levels up to get rid of the algae.

Greg

[duraleigh]

Greg,

Your assumption is correct. It will probably take some persistence to eliminate that yellow algae but consistent high levels of Cl and frequent brushing will do the trick.

Yellow algae is frequently misdiagnosed. Google the term and you will find some pictures to help you confirm.

[Turbo]

The pool is nearly full (3 or 4 inches to go) and I did some testing. Ph is 7.4, cl is 0, TA is 150 and CYA is 70 - 80, probably 80 (not sure about seeing the dot). If I understand correctly, I need to aerate if possible to get the TA down. I am going to start shocking and will look at the chart to see what I need. I was hoping CYA would have dropped further. I must have drained 3/4 of the pool.

I guess I will just run high cl for now. Any suggestions?

Greg

[duraleigh]

Hi, Greg,

For a plaster pool and CYA of 80, I'd put in enough Cl to get to 30ppm.

You'll surely get to breakpoint and clean up any "bugs" that may try to establish themselves.

If you have mustard algae, you can maintain that shock level for a few days, brush frequently and run your pump 24/7. Pooldoc advises that mustard algae takes high Cl and a lot of persistence.

After that "shock", you can let your Cl drop on down to 5-10ppm and keep it in that range the rest of the Summer.

[Turbo]

30 ppm sounds like a good plan. I put in 10.5 gallons of 6% bleach last night at about 12. At 7 this morning it was all gone. Maybe it left so quick because I tried to scrub a section of the wall with ascorbic acid when the pool was low but I didn't think there was that much that stayed in the pool. Maybe so. I guess that combined with the algae did it. I put more chlorine in this morning (4.2 gallons which is all I had). I will buy some more on the way home and get the ppm up to 30. When will the chlorine level stop dropping so much?

Should I try some ph minus to get my TA down or just hope my little bit of aeration does the trick? I am going to buy a jet that will shoot the water in the air hopefully to improve my aeration ability.

Greg

[duraleigh]

Hi, Greg,

I would focus on the Cl level for now. Your TA is not at all dangerously high and I would "fine tune" that issue later.

You still have a bunch of organics in that pool and chlorine is your answer. Get a bunch of it and keep bringing it up to 30ppm as much as three times a day if you can. It may take a few days, but your Chlorine will start to hold more and more. Your water will be crystal clear and then you can start to fine tune that Alk.

PS - I believe it was the algae that ate your chlorine...not the acid.