Possible Mustard Algae

Jul 19, 2013
62
Runnemede, NJ
Pool Size
10400
Surface
Vinyl
Chlorine
Salt Water Generator
A little history first - I made a huge mistake when I opened this season. I vacuumed and backwashed many times over the first couple days instead of just vacumming to waste. I have absolutely no idea what I was thinking. Stupid.

For the last couple weeks I've been having what looks like very fine dirt collect all over the bottom of the pool. This is accompanied by a yellowish green haze around it, and sometimes streaks if I let it go a couple days. If I run my hand over it, it disappears. I havent picked it up to feel it, but I'm pretty convinced it's not sand. I dont think it's pollen since there's not that many trees around.

I have an above ground salt water pool. My FC levels were consistently at 6 with a CYA at 70. Over the last week or 2, I've vacuumed to waste every couple days and then topped off the pool to bring the water back to the proper level. It comes back and after 3 days, it's a pretty good amount in the pool. It collects around the edges as well as in the middle, and really fills in the lower spots and wrinkles in the liner.

Here's my current levels from an hour ago:

FC 2
CC 0
PH 7.8
TA 100
CH 90
CYA Less than 30


My plan of attack is to start SLAM today, which I dont think will be a problem to pass tonight since the water is crystal clear and there are no other signs of algae, and then up to mustard shock level. Is this the right action or should I just go right to mustard algae level?
 
Please keep us updated with your progress and results, I'm having the identical situation with my pool as you are with the very fine debris on the bottom every day or two after vacuuming or brushing that won't filter out, even when vacuuming to waste. I am planning to SLAM to Mustard Algae level this weekend when I will be able to monitor FC level. I'm curious to find out what happens with yours to better prepare me for my experience. I'm really hoping this solves my problem, I've been struggling with this problem since last year and have tried pretty much everything else to get rid of it, with nothing working. Good Luck and keep us updated with your progress and results.

Thanks,
cruiser310
 
To clarify, you don't 'SLAM to Mustard Algae level'. You shock to the appropriate level of FC relative to your CYA level and hold it there (Shock level and Maintain) unitl you pass a OCLT, then you push it up to Mustard Algae level only after you completed a proper SLAM.

http://www.troublefreepool.com/content/125-slam-shock-level-and-maintain-shockingl
http://www.troublefreepool.com/threads/2177-Chlorine-CYA-Chart
http://www.troublefreepool.com/content/148-mustard-algae

Then, if you're me, you sorta pray it doesn't come back.
 
Please keep us updated with your progress and results, I'm having the identical situation with my pool as you are with the very fine debris on the bottom every day or two after vacuuming or brushing that won't filter out, even when vacuuming to waste. I am planning to SLAM to Mustard Algae level this weekend when I will be able to monitor FC level. I'm curious to find out what happens with yours to better prepare me for my experience. I'm really hoping this solves my problem, I've been struggling with this problem since last year and have tried pretty much everything else to get rid of it, with nothing working. Good Luck and keep us updated with your progress and results.

Thanks,
cruiser310

No problem. Adding 3-5 cups of bleach every couple hours. FC drops to 9 and I have to keep pushing it back over 10.
 
Sorry I havent updated, but I had to work yesterday and I had my daughters do the testing and adding. Here's a rundown of the last 36 hours or so. My CC was always 0 so I'm not listing that each time.

Thursday night:

Had to brush the pool twice today. Had some pockets of algae on the bottom.

4:30 pm - FC 12
6:00 pm - FC 10. Added 5 cups bleach
8:45 pm - FC 6.5 Added 12 cups bleach (Daughter did this one. I think it's off, but added 12 cups bleach)
10:00 pm - FC 18

Friday:

One very small patch on the bottom today. Brushed twice anyway.

1:00 am - FC 14
6:00 am - FC 13
10:00 am - FC 10 - added 4 cups bleach
1:30 pm - FC 13
8:30 pm - FC 10 - added 4 cups bleach
10:00 pm - FC 11 - added 2 cups bleach
11:15 pm - FC 13

Saturday:

6:00 am - FC 11 - added 4 cups bleach

It's going to be 98 degrees and humid today. Pool is full sun and my CYA is under 30. I have to go out and wont be home between noon and six. My SWG has been turned off since Thursday. Should I add bleach and bump the FC to compensate or should I turn the SWG on super chlorinate for that time?
 
Here's a couple. The small algae spots at in the shadow of the railing.
204cc3bd32ebde9b5b269f45f6bec082.jpg
31b4bebbe71a88d29e0154fc1edba2de.jpg
 

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You will pass the SLAM quickly......your water is very nice.

Why is your CYA below 30? I would add enough to bring it to 30 and then SLAM. I see no indication of mustard alge, either. I would do a normal SLAM but make sure you pass the OCLT and then go swimming.
 
CYA is below 30 because I vacuumed to waste what I thought was dirt and dust that the filter wasn't catching. 4 times. Stuff came back with a vengeance and had to vacuums every 2 days. Had to refill after each time. It would disappear if I disturbed it. It was a yellowish brown/green color.

Some of it came back and settled in the depressions again this afternoon. FC dropped to 6 because I had to go somewhere today. Bumped it back up and brushed again. It all poofed away as it always did.
 
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