Mustard algae or sand

[Tattooed Nurse]

Not quite sure what this could be in the bottom of pool. I run a robot vacuum almost every day and add cotton balls to the basket to collect tiny particles. After vacuuming the bottom looks great but by the next day, this has returned. It stirs up easily and doesn't cloud the water. How can I be sure that it isn't some kind of algae?
Current chemistry reading in photos as well

 

[thetekgeek]

Honestly - it looks a bit like dead algae to me.

Perform an OCLT - Perform the Overnight FC Loss Test (OCLT)

If you pass, great. IF you fail - SLAM - SLAM - Shock Level and Maintain

 

[Tattooed Nurse]

Honestly - it looks a bit like dead algae to me.

Perform an OCLT - Perform the Overnight FC Loss Test (OCLT)

If you pass, great. IF you fail - SLAM - SLAM - Shock Level and Maintain

Thank you for this!!! I will definitely do this! I learn something on here all the time!!

 

[jsygrls]

looking at your logs in early May your CL about a 3.0 with your Cya level thats just to low , so I agreeing with the geek on the OCLT.
So I'm talking out of school here because I do not have a SWG and I am not a TFP guide, but from all the past post I've viewed you need to be prepared with jugs of chlorine each coming season to supplement the SWG when the water temperatures impede your SWG from generating CL then when your at your range dial in the SWG.

YOU GOT THIS>

 

[Tattooed Nurse]

Honestly - it looks a bit like dead algae to me.

Perform an OCLT - Perform the Overnight FC Loss Test (OCLT)

If you pass, great. IF you fail - SLAM - SLAM - Shock Level and Maintain

And I do not have a sand filter just to be clear. I run glass media.

 

[Tattooed Nurse]

Honestly - it looks a bit like dead algae to me.

Perform an OCLT - Perform the Overnight FC Loss Test (OCLT)

If you pass, great. IF you fail - SLAM - SLAM - Shock Level and Maintain

Performed the OCLT as you recommended. FC last night was 7 and 6 this morning. So I'm assuming it must be dirt.

 

[sande005]

You didn't check CC - or at least log it. Is it .5 or less? That is one of the criteria, where all 3 need to be true.

The picture strongly suggests it is dead algae settling out. Your low level of FC last week bit you. A sand filter (even with glass media) can be less effective at getting the dead suspended stuff out, especially with a robot stirring some back into suspension. It will get it, but perhaps more slowly. If the amount does not greatly lessen over the next couple of days, you still have actively growing algae.

The criteria:
CC of .5 or less
FC overnight drop of 1 or less.
Crystal Clear and no sign of visible algae - alive or dead.

 

[TinFoilHat]

If you tested FC after dusk last night (30 mins after last adds), did not run your SWG overnight, left your filter on and tested FC this morning before sunrise then you have 1 CC which means SLAM. You are not supposed to lose any FC overnight because there is no UV or heat to affect it. Only organics can use FC at night. PS: you've been on here for a while now, it's time to fill out your signature so we can see what all the details of your pool and equipment are including test kit.

 

[Tattooed Nurse]

You didn't check CC - or at least log it. Is it .5 or less? That is one of the criteria, where all 3 need to be true.

The picture strongly suggests it is dead algae settling out. Your low level of FC last week bit you. A sand filter (even with glass media) can be less effective at getting the dead suspended stuff out, especially with a robot stirring some back into suspension. It will get it, but perhaps more slowly. If the amount does not greatly lessen over the next couple of days, you still have actively growing algae.

The criteria:
CC of .5 or less
FC overnight drop of 1 or less.
Crystal Clear and no sign of visible algae - alive or dead.

CC was 0 as it always has been. No I didn't record it. FC overnight drop was 1. This has been in my pool since we set it up and hasn't gotten any better or worse. So if it is dead algae, how do you purpose I get rid of it? I will do whatever is recommended to eliminate it. When we have used our hand vacuum, what is caught in the filter socks of the vacuum is gritty like sand or fine dirt but it always reappears by the next day.

 

[TinFoilHat]

Well then it's probably dirt blowing in over your pool and settling in it. It might be too fine for your glass filter to catch it.

 

[Tattooed Nurse]

If you tested FC after dusk last night (30 mins after last adds), did not run your SWG overnight, left your filter on and tested FC this morning before sunrise then you have 1 CC which means SLAM. You are not supposed to lose any FC overnight because there is no UV or heat to affect it. Only organics can use FC at night. PS: you've been on here for a while now, it's time to fill out your signature so we can see what all the details of your pool and equipment are including test kit.

I turned off the SWCG and tested an hour after it was turned off. Left it off all night, pump and filter run 24/7 always. How do I have 1 of CC if my test showed 0???? You can lose up to 1 of FC during the night as per the OCLT on here. And my signature is filled out. I use the Taylor K-2006 test kit and always have.

 

[Newdude]

How do I have 1 of CC if my test showed 0????

Total Chlorine (TC) - CC = FC.

One way of seeing it is if you lost 1 FC to over time, you cumulatively had 1 CC over the same time. A little is expected from normal operation, and there is a 1 drop test variance. You tested 0 CC, so take the win.

And my signature is filled out

Your profile is filled out. The Signature is here. Please put in all the details with model #s so they show below your posts and we can see them at a glance without going into your profile.