Brownish Red particles during SLAM - Is this dead mustard algae

[Karl103]

Question about some material I picked up with my vaccuum.

So I did SLAM 2 weeks ago - all went well. Then this week started noticing brownish "dust" at the bottom of the pool with some cloudiness. I did an OCLT and it was borderline with 0.8 chlorine loss. So I just decided to SLAM and then get the FC up to mustard algae levels.

This morning after 18 hours of SLAM at mustard algae level FC - saw some brownish yellow particles at bottom of pool (figured it was dead algae) Ran my robot vaccuum and when I cleaned out the robot filter noted a large amount of reddish brown colored debris - more red than brown. Bottom of the pool now looks great and water is clear.

My question is - is this what dead mustard algae looks like ?

Last testing numbers

FC = 35
CYA = 60

Thanks,

Karl

 

[Texas Splash]

Sounds like iron to me. Are you able to collect any of it? Have any pics? Are you on a a well or water supply known to have iron in it maybe?

 

[red-beard]

What color is the stone near your pool? My red sandstone/flagstone is constantly dropping a dust of red into my pool.

 

[Karl103]

I’ll get a picture next time I vacuum. I do not have high iron in fill water that I am aware of - not well water. No stone around to cause. Only seemed to occur during mustard algae SLAM. Unless what I thought was mustard algae was iron. Had that brown dust appearance when I started the slam and now less and less since SLAM began

 

[red-beard]

That isn't your pool in the picture? That looks like stone on the deck and the water feature. Is it textured concrete?

 

[Karl103]

I’ll get a picture next time I vacuum. I do not have high iron in fill water that I am aware of - not well water. No stone around to cause. Only seemed to occur during mustard algae SLAM. Unless what I thought was mustard algae was iron. Had that brown dust appearance when I started the slam and now less and less since SLAM began

Yes - that's my pool. There is tect

That isn't your pool in the picture? That looks like stone on the deck and the water feature. Is it textured concrete?

Yes - that's my pool - there is textured concrete I guess I misunderstood you - I thought that you meant red colored concrete. Its not red sandstone I do not think. Do you think the runoff from this concrete can cause an increase in iron ?

 

[JamesW]

See if the stuff is attracted to a magnet.

 

[willygee]

We get slight red dust sometimes on our below water seating ...i push it to bottom of pool and the vac does the rest.