Is this mustard algae?

tmkeith81

New member
Jun 11, 2024
3
Ecru, MS
Surface
Vinyl
Chlorine
Liquid Chlorine
I just found this forum a couple of months ago and I am so thankful I did! I have a 24’ above ground pool with a sand filter/pump. I have been testing and keeping my FC level at maintenance range but I keep getting reddish/brown clumps at the bottom of my pool. My water is crystal clear. The robot vac picks most of it up but the next day or later that same day, it’s back. I have manually vacuumed and before I can get one side of the pool done and return to the other side, the brown clumps are back. They seem to float away in a cloud if I rub them with my foot. I was gone over the weekend and when I returned, I threw the robot vac in and it couldn’t suck up the spots so I had to brush them up. The water will cloud a very small amount but within a couple of hours or less, it’s back clear and the spots are back. Most everything I read points to mustard algae.
My test numbers were:
FC 3.5
CC .5
PH 7.5
TA 99
CH 108
CYA 30

I decided to SLAM in case it’s mustard algae. I added up to my SLAM FC of 12 last night. This morning I checked it and FC was 10.5 with CC .5. So my OCLT was 1.5 and I know we want it no more than 1.

Do yall think this is mustard algae? Should I continue to SLAM and see if it goes away?

I live in MS so it’s HOT!!! I also have well water and have a gravel drive with constant traffic as my husband owns his own construction business from home. I often wonder if this may be dirt instead.

Thanks!
 
The oclt points to something alive.
Follow the SLAM Process - be sure to pass all 3 end of slam criteria including no recurring algae (dead or alive)
Then proceed to the MA protocol for 24 hrs. to be on the safe side.
Algae (mustard or otherwise) will usually change color after some time with exposure to slam level fc (bleach out/turn greyish/white) dirt will not do this.
Afterwards you may want to maintain fc at or above MA target levels for some time as listed on the attached chart in the article. Some choose to do this for the rest of the season.

One other note- you may find that in this area a cya of 30 at this time of year isn’t enough protection from the sun & this can lead to maintenance fc levels dipping too low (below minimum) at times because of our intense uv.
After completing slam & ma protocols you may want to bump cya up to 40 or even 50 - be sure to increase your maintenance fc levels accordingly.
While 3ppm is technically ok for your cya it is dangerously close to minimum-
 
Thank you so much for
The oclt points to something alive.
Follow the SLAM Process - be sure to pass all 3 end of slam criteria including no recurring algae (dead or alive)
Then proceed to the MA protocol for 24 hrs. to be on the safe side.
Algae (mustard or otherwise) will usually change color after some time with exposure to slam level fc (bleach out/turn greyish/white) dirt will not do this.
Afterwards you may want to maintain fc at or above MA target levels for some time as listed on the attached chart in the article. Some choose to do this for the rest of the season.

One other note- you may find that in this area a cya of 30 at this time of year isn’t enough protection from the sun & this can lead to maintenance fc levels dipping too low (below minimum) at times because of our intense uv.
After completing slam & ma protocols you may want to bump cya up to 40 or even 50 - be sure to increase your maintenance fc levels accordingly.
While 3ppm is technically ok for your cya it is dangerously close to minimum
Thank you for replying! I will continue with the SLAM process and note if it changes color. Nothing is on the walls and it’s minimal in the bottom so hopefully it won’t take too many days to get rid of it. I will also bump up my CYA.
 
Manual vacuum using the skimmer suction vacuum head. Looks like dirt / pollen to me.

Since you've already gone up to SLAM and failed OCLT, continue SLAM as well (topping up to 12).
 
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Based on the pictures, I think that it is probably mustard algae.

Below is a picture of mustard algae.

1720627367288.png

 
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