i see that your mustard algae description IS different than what i have. "as a layer of silt" and "nickel sized spots" sounds different that the layer of yellowish streaking on bottom or slope of pool that i see. i sure so after years of thinking i had mustard algae (because a tech told me so over the phone...) i think i am coming to realize that i really don't have it after all and am instead struggling with plain old algae. I really do hope you are finished you battle!So at the beginning of this season I got a new vinyl liner replacement. I hired the company who installed it to come once a week to clean and add chemicals (after 15 years of taking care of the pool myself, I decided to take it easy for a change). All was well until a few weeks ago. I suspected it was MA and the pool tech confirmed it. That being said, I'm not totally convinced that it is in fact mustard algae. It appears initially on the floor near the returns as nickel sizes spots, greenish-yellow in color. then it settles in larger areas on the rest of the floor but as a layer of silt that clouds up when brushed. It also is on the walls but it's harder to see it there. I see it when I brush the walls. It comes off easily with brushing. I believe the forums suggest that if it appears on the walls then it's not pollen, but IDK.
So I did the SLAM for about 2 weeks as I said in the earlier post. I use liquid chlorine 12.5% sodium hypochlorite bought from the pool store. (In the 2 weeks I used about 15 gallons of it.) Then I shocked at Mustard Algae level for 24 hours. I passed the OCLT during SLAM. The pool looks pristine clear, my free chlorine level is coming down now. I am closing the pool tomorrow. Hopefully I won't need to resume this battle next year.
Hang in there Chaya. I used to shock using powdered shock but I now use the liquid instead. It's much better in my opinion. You can get 5 gallon containers of it for about $20 at the Home Recreation store in Brick. They also have it in 1 gallon bottles by the case.
I also have a question for the experts here. Is it alright to use "sodium thiosulfate pentahydrate Na203s2 dechlorinator" to lower the chlorine level in the pool so I can properly balance the water for closing? Thanks for your expertise!
Please advise - why are you closing tomorrow, wouldn't the temp of the water go down to about 60 in just another 2-3 wks? my pool was 65 degrees today and i thought that was the whole point in waiting for long to close (so that we could open cleaner). Also, i'm wondering why you would want to lower the chlorine content of the water. please advise, because i wanted to make sure there was plenty of chlorine in it when i closed. is that wrong?
Lastly, thank you for the advice on the liquid chlorine. My issue is the extra trip to the store and the weight of the item and the quantity i have been using. Sounds like an awful lot of work. Can you explain why you found it superior? Also, did you find it difficult to have to add the chlorine daily (instead of putting 3" tabs into a chlorinator and then being done for the week)? I really would like to hear because i see that liquid is the recommended chlorine again and again, but i have only used it in limited amounts and never thought it was very practical.