For some time I kept overlooking the stuff I could brush off the floor of my pool that looked like slightly greenish (on a light blue Diamond Brite) dirt. I thought when I replaced my robotic pool cleaner, that would fix the problem. Just of note - I've read several posts here when people ask if the person questioning whether they have mustard algae have brushed the sides to try to distinguish between things like pollen and algae, and I can tell you that I've never noticed the stuff brush off any sides, just the bottom. Also I began increasing my SWG % significantly, which I thought meant my salt water cell was getting towards the end of its life. I was able to maintain my FC at a high SWG %, but eventually I realized I have mustard algae.
Unfortunately I realized I needed to SLAM right after adding CYA to target 75 (higher water in FL, SWG), so that left me with the following chemistry:
CYA ~72
shock target 28+
pH - brought down to 7.2 before starting SLAM
TA 80-90
CH 240-250
CC have always been <0.5
After a few days there was no more stuff brushing off the bottom of the pool, and the water became clearer. I have cleaned the filter a few times since then. I've removed all the lights out of their sockets, which did have algae behind them, and i've run the pump 24/7. I've run my robotic cleaner for hours daily, and the fine filter is completely clean now.
The problem is that I never pass the OCLT, and it's been over 12 days. It's been raining a lot the last few weeks, especially at night, which obviously dilutes the water. Also my pool automatically drain the water when it gets to a certain height. I rechecked CYA today, and it's down to ~54-60 now from ~72 12 days ago, so I've actually been at a higher FC than I should have given the lowering CYA. Some night and morning FC readings, from the first night:
night next morning
35 27
29 27
29 26.5
29.5 26
29.5 28. 5
28 26
27. 5 25.5
28.5 26
I ran out of FAS-DPD solution from measuring such high chlorine. I just added similar amounts of chlorine as before, then continued last night. I decide to measure the chlorine three times because I was wondering how much standard error there is in the measurements with FAS-DPD, and I did find some. At night my three measurements were
30.5, 32.5, 31.5
The next morning :
30, 29, 30
Ths evening, the FC was 28, which is a 1- but probably 2-point drop in FC over the daytime - it was an overcast day but was hot enough.
If you noticed, the 5th day had a one point drop only in FC, but I did not have time that morning to look at the mustard algae shock numbers , so I just measured again that night, and it dropped more than 1 so I kept on going. My question is, I do not see any sources of algae in the pool. I have no metal stairs or anything like that. I've taken out the pool light from their socket and left them floating in the pool and also left them out on the deck. Given that I had such the high target of chlorine because of the high cya, could it be that the one point drop makes sense with a lower target slam number, and as you get you higher free chlorine levels, there is a higher standard deviation on testing and so a larger than 1 point drop would be a fine time to stop slamming? Thanks for reading through this, your help is appreciated!
Unfortunately I realized I needed to SLAM right after adding CYA to target 75 (higher water in FL, SWG), so that left me with the following chemistry:
CYA ~72
shock target 28+
pH - brought down to 7.2 before starting SLAM
TA 80-90
CH 240-250
CC have always been <0.5
After a few days there was no more stuff brushing off the bottom of the pool, and the water became clearer. I have cleaned the filter a few times since then. I've removed all the lights out of their sockets, which did have algae behind them, and i've run the pump 24/7. I've run my robotic cleaner for hours daily, and the fine filter is completely clean now.
The problem is that I never pass the OCLT, and it's been over 12 days. It's been raining a lot the last few weeks, especially at night, which obviously dilutes the water. Also my pool automatically drain the water when it gets to a certain height. I rechecked CYA today, and it's down to ~54-60 now from ~72 12 days ago, so I've actually been at a higher FC than I should have given the lowering CYA. Some night and morning FC readings, from the first night:
night next morning
35 27
29 27
29 26.5
29.5 26
29.5 28. 5
28 26
27. 5 25.5
28.5 26
I ran out of FAS-DPD solution from measuring such high chlorine. I just added similar amounts of chlorine as before, then continued last night. I decide to measure the chlorine three times because I was wondering how much standard error there is in the measurements with FAS-DPD, and I did find some. At night my three measurements were
30.5, 32.5, 31.5
The next morning :
30, 29, 30
Ths evening, the FC was 28, which is a 1- but probably 2-point drop in FC over the daytime - it was an overcast day but was hot enough.
If you noticed, the 5th day had a one point drop only in FC, but I did not have time that morning to look at the mustard algae shock numbers , so I just measured again that night, and it dropped more than 1 so I kept on going. My question is, I do not see any sources of algae in the pool. I have no metal stairs or anything like that. I've taken out the pool light from their socket and left them floating in the pool and also left them out on the deck. Given that I had such the high target of chlorine because of the high cya, could it be that the one point drop makes sense with a lower target slam number, and as you get you higher free chlorine levels, there is a higher standard deviation on testing and so a larger than 1 point drop would be a fine time to stop slamming? Thanks for reading through this, your help is appreciated!
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