Is this mustard algae?

[Kiki Di]

I’ve been following the slam process for 3 days and this shows up every day.

 

[kellyfair]

Looks like regular algae to me. Are you raising your chlorine to SLAM level several times per day?

Can you post your most recent test results?

 

[Kiki Di]

I add chlorine 4 times per day. The first day I was trying to maintain 10 ppm but it dropped too quickly during the day. Yesterday and today I go all the way to 20ppm and the lowest it has dropped was to 12ppm.
TA 140
PH 7.5 when I started SLAM
CYA 20
CH 180
FC 15
CC 0.5
overnight FC drop test has been 1 or under all nights and I'm vacuuming and brushing daily.

 

[reggiehammond]

You need to raise your CYA as 20 is likely no sufficient to maintain FC levels (UV is burning off your FC between additions too with low CYA).

There's no need to go over SLAM levels for CYA - it is potentially destructive to your liner and has no benefit to resolving algae.

 

[Kiki Di]

What should I raise the CYA to? Can I do that with high chorine levels? I just added chlorine to bring it back near 20ppm

 

[JJ_Tex]

What should I raise the CYA to? Can I do that with high chorine levels? I just added chlorine to bring it back near 20ppm

30-40 CYA is what is recommended in the SLAM directions:

SLAMing an outdoor pool is most effective when CYA is around 30 to 40. Below 30 you lose too much chlorine to sunlight.

I would bump it up to 30 or 40, then keep your FC at 12 or 16 respectively for the remainder. Nothing to really do now to drop your chlorine as it should quickly reduce due to burnoff from the sun and algae, but no sense in going over SLAM level in your future chlorine adds.

 

[Kiki Di]

Can I raise the CYA while FC is 20 ppm or do I need to wait until tomorrow after the sun burns up some of the chlorine?

 

[JJ_Tex]

You can raise it now no worries. It will actually reduce the harshness of your chlorine and minimize the risk to your liner.

Note that in a pool your size, you only need about a half a pound of dry stabilizer to raise your CYA by 10 so you don't need much.

 

[Kiki Di]

You can raise it now no worries. It will actually reduce the harshness of your chlorine and minimize the risk to your liner.

Note that in a pool your size, you only need about a half a pound of dry stabilizer to raise your CYA by 10 so you don't need much.

Thank you!