White mold?

[brunoforestier]

Today's test results:

2.0 FC
0.0 CC
7.6 PH
50 TA
300 CH
CYA under 30

I've got floating white material on the pool surface.

Everything seems to be in order with water chemistry.

I've read on google that this is white mold, but not a lot of amazing threads here that match what I'm seeing.

 

[Texas Splash]

I'm not sure I'd go down the mold road just yet. Understandably you maintain a low FC because of the low CYA for an indoor pool. An OCLT would probably seem redundant in your case, but I wonder, have you tried increasing the FC to 10 for a day or two (like a SLAM level) in case there's something in the water that requires the extra oxidation? Also, I don't see it in your signature, but what type of filter do you have?

 

[Mdragger88]

I do see a window so an Overnight Chlorine Loss Test probably wouldn’t hurt to try. Also it kinda looks like bubbles/foam & it is near a jet. Perhaps there’s air getting into the system somehow or as Pat mentioned some other contaminant/product ? Can u catch the stuff & put it on a paper towel?

 

[brunoforestier]

I'm not sure I'd go down the mold road just yet. Understandably you maintain a low FC because of the low CYA for an indoor pool. An OCLT would probably seem redundant in your case, but I wonder, have you tried increasing the FC to 10 for a day or two (like a SLAM level) in case there's something in the water that requires the extra oxidation? Also, I don't see it in your signature, but what type of filter do you have?

Sand filter. Just replaced this winter, also.

I have not tried SLAM yet -- will do. thanks

 

[brunoforestier]

I do see a window so an Overnight Chlorine Loss Test probably wouldn’t hurt to try. Also it kinda looks like bubbles/foam & it is near a jet. Perhaps there’s air getting into the system somehow or as Pat mentioned some other contaminant/product ? Can u catch the stuff & put it on a paper towel?

What's a good method for evaluating air getting into the system? It is quite old, I think it turned 50 this year.

 

[brunoforestier]

Follow-up question:

Is it safe to swim in today?

 

[Mdragger88]

The likely culprit for bubbles/air in the system is a suction side leak. Most often the pump basket lid oring is the easiest 1st place to check & lube.
Here’s a way to check other things as well

It is safe to swim if fc is anywhere between minimum & slam level for your cya FC/CYA Levels & u can see the bottom of the pool for safety.