Please identify

[spiazza]

I am trying to identify these discolorations in the deep end of my pool. Algae or stains? They are brown discolorations that don't move when brushed, appear to be slowly spreading (in my opinion), hard to see when the sun is shining on the water.

I was advised they could be organic and go away with time. I haven't seen them fade yet and the pool has had 8+ppm of FC in it for several weeks.

CC in less then .5 and FC overnight test passed.

The stains don't translate well on camera but here are some samples anyway. The stain is browner and more pronounced in person.

 

[waste]

OMG!!! You've got black circles on the floor of your pool (wait a minute - you drew those in to show the problem areas )

I'd be willing to go with organic unless someone applied a little green stain to your MD cover. I'm afraid you have something trying (fairly successfully ) to grow in the deep end. Other than the MD, is there any circulation going on down there - like a return pointed into the bottom of the hopper? One of the members here (actually he posted it on PF) Matt4X4, had some posts about a persistent algae which I dubbed "Matt's Mud" or "4X4 algae" found here on Pool Form. As I recall, treat it as if it were mustard or black algae and it will eventually leave the pool

I know I've seen Matt here of late (HI Matt ), perhaps he'll see this and have an update on the stuff

 

[frustratedpoolmom]

Organic stains usually fade with proper FC levels, mine did. What's your CYA level?

 

[spiazza]

CYA level is 70. I'm hoping they fade over time. I've been keeping FC at 8ppm. I don't think algae level shocking is going to do much. It might just be a waste of time and $.

 

[frustratedpoolmom]

I'd say it took about 2 months for mine to vanish completely. It was a very gradual fading.

 

[JasonLion]

You could try placing a Vitamin C tablet on a stained area for 30 seconds and see what happens. If they are iron stains, the area where you applied the Vitamin C tablet will get significantly lighter or clear up completely.

 

[spiazza]

I wouldn't mind trying the vitamin C test but how to suggest I place a test tablet to the bottom of the 8' deep end?

 

[reebok]

just put it there. it should stay somewhat in place. your areas are so big that it should stay on a spot even if it moves slightly when you swim back to the surface. or you can swim down and hold it. even if it's only 20-25 seconds it should make some kind of change I would think (if it was going to at all). or you could get maybe a 3/4" pvc pipe about 10' long. put it on the spot and drop the tablet down it. if you didn't want to retrieve it you could probably brush it around. they dissolve pretty quickly.

 

[Sallie]

OR you can drop it into the water near where one of the stains is and then when it gets to the bottom, push it to where you want it with your brush. That's what I did, didn't have to get in the water at all.

 

[spiazza]

Thanks for the suggestions. I will try them and let you know.