Mis diagnose Mustard Algae??

[Whatrymes]

Trying to solve a problem I’ve had every year of pool operation. I get a Brown/gray sediment with a hint of yellow that settles into “lines” on the bottom of the pool. It seems to be “seasonal” and periodic. I’ll deal with it now and again in late August. If I had to guess I’d say some kind of powdery substance is in suspension and when the water calms down it settles out in these lines. Vacuums rather easily but seems to return pretty quickly.

When I go to the pool store they say “Mustard algae!” and I leave with a ton of chemicals which seem not to help much. I’ve been reading up on mustard algae, it says, “a yellow slime on the walls” and “tends to cling to the walls” both of which I’ve seen neither of.

FC 4
TC 4
pH 7.4
TA 150
CH 250
CYA 40

. . . sparkling beautiful blue water.

Thank you.

 

[Butterfly]

Well, if you are able to collect any and feel it, pollen will feel squishy while algae will feel slimy.

Have you used skimmer socks? They will catch lotsa pollen, if this is the case.

 

[duraleigh]

Ditto what BF just posted.

It is almost surely not mustard algae but rather dead algae or pollen.

That your pool water is nice and clear and your test results are good would seem to indicate it's not algae at all.

However, when I let my FC levels drift too low...even for 12-24 hours, the next dose of chlorine usually results in some dead algae falling onto the pool floor (even though I couldn't tell I had any) and it looks almost identical to what you are describing.

Perhaps you could dose with chlorine more frequently or up the level a bit to around 6-8ppm and see if that stops it. I think it will.

 

[Whatrymes]

Ditto what BF just posted.

It is almost surely not mustard algae but rather dead algae or pollen.

That your pool water is nice and clear and your test results are good would seem to indicate it's not algae at all.

However, when I let my FC levels drift too low...even for 12-24 hours, the next dose of chlorine usually results in some dead algae falling onto the pool floor (even though I couldn't tell I had any) and it looks almost identical to what you are describing.

Perhaps you could dose with chlorine more frequently or up the level a bit to around 6-8ppm and see if that stops it. I think it will.

You got me thinking. That might be a common denominator. FC fell too low and then algae and then "dust." I'll keep an eye on that.