Crystal Clear water with very small areas of Algae

[keagle]

I use a solar cover and this morning after rolling it up, there were areas of algae, mostly where the sides meet the floor. I check chemicals daily and keep my pool clean. I also brush the walls from time to time. This has been happening on and off this season. Looking at the pool I knew the water was in balance - it was crystal clear. Using the TF-100 test kit, these were my results: FC 3.5, TC 4, TA 100, PH 7.5, CYA 30. I usually have FC/C 4-5. I use liquid bleach. Prior to the rain the other day I had 0 CC. I can't figure out why I'm seeing algae. Can it be that my water isn't circulating enough? I have a variable speed pump, running all the time but I have to check that it is adjusting. Usually in the morning I manually turn it up to high. I have shocked it - bringing chlorine up to 12 about a week ago. I usually don't have to shock the pool once I get everything in balance. My pool is 33,000 gal, vinyl liner. (My liner is old and faded - could that be a problem?)

 

[JoeSelf]

It could be lack of circulation and lack of weekly brushing. You need to SLAM with algae. To clear the pool. How Long did you keep it at 12? Have you done and OCLT?

 

[keagle]

I probably kept it at 12 for a day. In the morning it was lower by .5 or 1. I through out the papers that had the numbers, but I remember I was not losing too much chlorine.

 

[JoeSelf]

Still need to SLAM if you have algae.

 

[keagle]

Thanks. Will do but need to wait until Friday. (I noticed my last thread should say threw out. Hate when I do that.) I also noticed you are from Glassboro. My son goes to Rowan University. Thanks again. Have a safe and happy July 4th

 

[JoeSelf]

Thanks, you too. My son also goes there.

 

[keagle]

I started my slam, even though my pool was crystal clear because it had some spots of algae. After vacuuming, my cc was 0. I plan to check it again in a few hours, and if my cc doesn’t go above .5, do the overnight test. Am I correct or should I bring the chlorine up to shock level again?

 

[JoeSelf]

Keep FC up to SHOCK LEVEL for your CYA. As much as you can. The important part of slaM is MAINTAIN.

Visible Algae means you need to SLAM, no matter what the water looks like.

 

[keagle]

I just checked the FC and CC. FC & TC are 12. I will bring the chlorine up to 16, shock level for cya40. How do I know when I’m done with slamming? This morning there was only dead algae. Right now the water looks good, clear and no algae.

 

[IceShadow]

Clear water with no visible algae (alive OR dead), CC under 1, and no loss overnight is the criteria to pass a SLAM. Feel free to test it tonight after sundown / before sunup and if you don't have more dead algae gathered on the floor then you should be set.

 

[keagle]

Yesterday I checked chlorine. FC was 16, cc 16 at 6:00 & 7:40pm. This morning it was the same at 8am, with no signs of any algae. I brushed parts to see if any dead algae was there and it was clean.

Should I maintain shock level today to make sure all is good?
Can I use my Dolphin auto cleaner when chlorine is at 16?