Help,not sure what this is on bottom of pool

[jstonemo]

I am having the same exact problem that I posted about earlier today. I live in the KC, MO area.

[matt4x4]

Waste - Thanks for that, noe I gotta go get some paper towels and clean the coffee off my monitor!!!! LMAO
With regards to your question, I'm in southern Ontario (canada), Now having reread the posts from tuesday on, I'm beginning to think it does have something to do with people's locations being closer to rural than urban, we have lots of "feed corn" fields around our area, the soil is high in clay content, however, the "mud" is definitely not inert clay dust and could never multiply that much.
Around here, farmers also fertilize in spring, but it's usually so early, your pool is likely not open then, farmers around here also fertilize with liquid manure during fall before they turn the fields over - this was the case a few weeks ago, since it really stunk for a few days.

From my experience, this is what I have leaned in 3 years about the "mud":
Year one - nothing, thought it was dirt, then it was too late - shock shock shock, brush brush brush...
Year two - remembered year one, shock shock shock, brush brush brush but only to the typical 15 ppm, nothing really changed other than the mud very slowly became more mud - slower than year one. Finally had enough, it was end of season anyways, I dumped in my remaining chlorine and voila, within a few days, the mud was killed off.
Year three - this year, almost like clockwork, same time, different year, I started seeing our old friend "mud" again, this time, being wise about how mr mud works, I immediately dumped everything I had in the pool, brushed vigorously for about 2 days and all was well.

Swimmer load does have something to do with it too, I think this stuff set in when the circulation of the water is less optimal, we stopped using the pool on a regualr basis after the first week in august, meaning the water does circulate less, however, I was on top of my chlorine levels DAILY even though we were using the pool less.
First signs of this mud are always past the far side of the steps from the return (my worst spot for good circulation).

At this point, I'm just glad i have a way to control it, 20-25 PPM does seem to be kind of high, but heck, if 15ppm doesn't do it and 25ppm does, it's an easy fix and I'm not questioning it.
Since my chlorine levels and all other levels were in perfect range this year for sure, I can also determine that this stuff is pretty resilient to the effects of normal chlorine levels.

Oh, I wrote some more here:
http://www.poolforum.com/pf2/showthread.php?t=5612

[Rangeball]

It sure sounds like yellow algae.

[CallMeIshmael]

It sure sounds like yellow algae.

Ahhh, ignorance was bliss... It appears we have a similar thing happening in our pool as well this year. It's the first time I've noticed the brownish "mud" on the pool floor and it matches the descriptions here.
I've also noticed that the shade-side wall of our pool (fiberglass) is slightly more yellow than the sun side in an area that was bypassed by the return flow.
Lessons learned: I'll be adopting Matt's 3rd year approach to killing off whatever this stuff is, and hope the shock will also clear out what may be "yellow algae sheets" (ewww!) on the shade wall. I'll also be adding a return eyeball to direct flow (and chlorine or other treatments) towards that wall.

Thanks for a helpful thread & I hope the heavy shock/brush routine works out!

[itstoohot]

I think you are dealing with mustard algae. I had a wake up call with this stuff in June. We noticed it towards the end of last year and thought nothing of it until it consumed our pool this year. Our daily regimen was to increase the chlorine to shock level (we intentionally overshot this regularly) in the morning and evening, vacuum, change cartridges (we have a cartridge filter and an extra set of cartridges) and run the filter 24/7. We also used skimmer socks to grab what they could. At the worst, it took nearly 2 weeks to be rid of it. Now, we seem to get it whenever we use the solar cover or if I haven't brushed the pool in a while. If caught early, we just shock, brush and let the filter take care of it and it's typically gone the next day.

My fight - http://www.poolforum.com/pf2/showthread.php?t=3287

[haze_1956]

I have been getting the same thing for a few weeks. (the stuff in the OP's photo )

Had this stuff sitting at the bottom for about 5 days, a bit more appearing each day. Has a nice brownish green color and sort of smears a little when you vacuum it.

It seems to be pollen and dust collecting in the little divots in the pool floor. It only appears on the floor, never see any on the walls. We've had no rain to wash the pollen and dust into the gound, so I think it is blowing around and settling in the pool.

While it was there I didn't have an increase in Cl demand or any CC reading. This is another reason I tend to think it wasn't algae.