What to Add? Algae or no?

[Cchandler]

So I have had this material on the bottom of my pool for about a week. It looks like dirt....not yellow or black. My water is crystal clear and other than those spots coming back up, I have had no problems. My question is how can I tell if it is algae and would my CC be 0 if algae was in the pool?

Last REadings:
FC: 3.7 CC: 0.0
CYA: 45
Alkalinity: 50
Ph. 7.5

Should I raise my Alkalinity? Could that be the problem?

 

[Richard320]

The problem is the FC is too low. Your minimum before you add more is 4 FC. How you got 3.7 on a drop test is beyond me. It's not a factor of ,2 (25 ml sample) or .5 (10 ml sample) but it's too low regardless. 4 is the absolute minimum. When you add, you ought to shoot for 7 or 8 FC.

That stuff --- does it look like dust bunnies and does it go *poof* and disappear when you get close to it with brush or vacuum?

 

[Cchandler]

Yes, it does kind of go "poof" and disappear when I vacuum.
My FC was 3.8 not 3.7 just a typo

 

[Richard320]

Yes, it does kind of go "poof" and disappear when I vacuum.
My FC was 3.8 not 3.7 just a typo

That's dead algae clumping up.

You need bleach. Lots of it. Ideally, a SLAM Process

 

[Cchandler]

Thank you!