Need Help with Stubborn Mustard Algae

[Mdragger88]

Couple questions….
Have you scrubbed every nook and cranny? Inside light niches, drains, ladders (inside and out), flushing water features daily etc.
what type of filter do you have?
& what media are you using?
Also, while vacuuming to waste every time isn’t necessary during slam it can be helpful to remove the bulk of recurring debris that may be making its way through the filter over & over.
The sudden reoccurrence at higher fc levels is strange. (Assuming it was always this mustardy looking algae from the get go)
Generally, if you fully completed the
SLAM Process and there was no visible algae (dead or alive) then usually what happens is mustard algae then shows itself again as fc levels fall back to normal. It is “resistant” in that its able to thrive at normal maintenance fc levels not slam or mustard algae slam levels.
The ma slam level is only to be held for 24 hours as its more about being the final nail in the coffin for reassurance rather than the main cure. More time risks damage.
The main cure is regular slam.
Have you physically gathered & touched any of the “debris” to see what it feels like?
Slimy= algae, gritty = sand/dirt/debris.
Is it possible that you are witnessing some precipitation of iron due to the high fc?
Patiently awaiting your pics…

 

[doc19]

Thanks for your replies, all. The FC is down to about 40 and the MA is finally clearing. I don't have any pictures to show because there is very little left. I will continue following the process. I was just getting impatient and was sure I was missing something. I appreciate your insights!

 

[Bperry]

Thanks for your replies, all. The FC is down to about 40 and the MA is finally clearing. I don't have any pictures to show because there is very little left. I will continue following the process. I was just getting impatient and was sure I was missing something. I appreciate your insights!

Pictures of the water color are what helps as well. Make sure you do an OCLT once the FC is back in normal range.

 

[doc19]

Hi, all. I am still having issues with Mustard Algae and have been unable to complete the SLAM and can't pass the OCLT. I am really stumped, and I am not sure what to do next.

Here are my numbers:

• FC: 18 (I am testing multiple times a day and following the Chlorine/CYA chart; I have been keeping it on the higher side because the recommended level is not working)
• CC: .5 (I am never over .5 and for some tests it is 0)
• pH: 7.5
• CYA: 40 (It had dropped to 30 over the last week so I added a small amount and am just under 40 when I test)

Here is what I'm doing:

• Brushing the ENTIRE pool 3+ times a day. I have removed the ladder and pool light. I brush inside skimmers, returns, and stairs.
• Vacuuming as frequently as needed to remove debris, but there isn't much lately
• I keep leaves out of the pool and check skimmers multiple times a day

The pool is 20x40, rectangular and crystal clear and looks great unless you happen to look at the seams in the liner or one specific corner in the shallow end. It is slimy and not gritty/grainy. When it was worse, it did puff up when you brushed it, but it is very minimal now, so it no longer puffs up. I am 100% certain that it is not pollen or regular debris. And, it continues to grow only in the exact same spots. I am trying to brush those spots rigorously, but it's really hard to get at the seams, especially when the water is only 50 degrees and I can't get in. I brush in multiple directions and go back and forth over it several times in a row.

I have not added any other chemicals/algaecides and only follow TFP. I have the TFP-100 Salt kit and have been using it for almost 4 years, so I feel decently comfortable that I'm testing correctly. I had originally turned off the SWG, but honestly, this has gone on for so long that I just can't afford to only use liquid chlorine any longer. I turned the SWG back on about a week ago to help me keep the chlorine levels up but I'm supplementing with liquid chlorine to keep it steady. I also backwash the filter regularly and the sand was replaced in late summer last year, so it should be in good condition.

I do not have a waterfall or water feature. I brush the cover of the main drains, but I can't remove them and brush inside because the water is too cold. I know that it's possible that mustard algae could be inside the main drains, but I'm leaning away from this simply because the biggest problem areas are in the shallow end, almost 40 feet away. Perhaps that doesn't matter, but that's been my logic so far.

I'm attaching pictures of two seams where it continues to accumulate and the corner in the shallow end where it appears semi-regularly. These pictures were taken yesterday morning when the FC was even a bit higher at 20.5, and I have been careful to never let the FC drop, so I am completely confused.

Please help! I don't know if I'm doing something wrong or what I'm missing. Thank you!

 

[Mdragger88]

Sorry you’re still struggling!
A couple things…
*Take your cya sample indoors and let it warm up to room temperature before testing to ensure your cya measurement is accurate. It can read falsely low at lower temperatures.

*For the drain you can use a pvc pipe to direct some liquid chlorine into it. Be sure to brush the area well as to not bleach your liner. You may also want to spray it out with the water hose nozzle on blast first. You can try attaching it to your pool pole - maybe with an accessory still attached so you don’t accidentally scrape the liner with the end of the pole.
*Check your weir door foam. On many weir doors it is removable and the hidden side can be nasty.
* what type of filter do you have?

 

[doc19]

Sorry you’re still struggling!
A couple things…
*Take your cya sample indoors and let it warm up to room temperature before testing to ensure your cya measurement is accurate. It can read falsely low at lower temperatures.

*For the drain you can use a pvc pipe to direct some liquid chlorine into it. Be sure to brush the area well as to not bleach your liner. You may also want to spray it out with the water hose nozzle on blast first. You can try attaching it to your pool pole - maybe with an accessory still attached so you don’t accidentally scrape the liner with the end of the pole.
*Check your weir door foam. On many weir doors it is removable and the hidden side can be nasty.
* what type of filter do you have?

Thanks! For CYA, I let it warm up first and also had my readings double-checked at the pool store to make sure I wasn't making a mistake, so I'm pretty sure it's accurate. I have a sand filter and the sand was changed last fall.

Great idea for the drain! I will have to pick up some pvc to try that. Did you mean spray out the PVC first or the main drain? I will also check the weir doors. I haven't replaced them since the beginning of the season last year and that could definitely be a possibility.

As an update, I turned on the heater to get the water temp to 60 degrees and used the robot all day yesterday and will put it back in today. Our Polaris can be used in 55-95 degree temperatures and I thought that it would help keep some continuous movement in the pool.

 

[Bperry]

Thanks! For CYA, I let it warm up first and also had my readings double-checked at the pool store to make sure I wasn't making a mistake, so I'm pretty sure it's accurate. I

you can save yourself the time for next one by not even bothering with the pool store test. They good up the CYA test more often then the other it seems. I was able to drop my CYA in half (according to the store test) by just testing the same water at another store.

 

[doc19]

you can save yourself the time for next one by not even bothering with the pool store test. They good up the CYA test more often then the other it seems. I was able to drop my CYA in half (according to the store test) by just testing the same water at another store.

That's interesting. We only have one here and I only use it when I'm concerned that my readings are off and need a double-check. Their results were the same as mine for yesterday, so I think they are probably right. This whole process has been so perplexing that who knows at this point...

 

[Bperry]

That's interesting. We only have one here and I only use it when I'm concerned that my readings are off and need a double-check. Their results were the same as mine for yesterday, so I think they are probably right. This whole process has been so perplexing that who knows at this point...

Sometimes they get it right and other times they don’t. That’s the problem. You never know when which is which. I’d venture to say it’s literally the most common cause of frustration for folks visiting the site. The related issue is that their equipment doesn’t usually test FC levels needed if you are following along with TFP. Most times they can’t test above 10ppm and even at that level the error tolerance is wildly large. You do yourself no favors by assuming their testing is more accurate than your own kit. It’s been proven over and over again for the 5 years I’ve been around here.

 

[Mdragger88]

Thanks! For CYA, I let it warm up first and also had my readings double-checked at the pool store to make sure I wasn't making a mistake, so I'm pretty sure it's accurate. I have a sand filter and the sand was changed last fall.

Great idea for the drain! I will have to pick up some pvc to try that. Did you mean spray out the PVC first or the main drain? I will also check the weir doors. I haven't replaced them since the beginning of the season last year and that could definitely be a possibility.

As an update, I turned on the heater to get the water temp to 60 degrees and used the robot all day yesterday and will put it back in today. Our Polaris can be used in 55-95 degree temperatures and I thought that it would help keep some continuous movement in the pool.

I guess if the pvc was dirty you would wanna spray it out but I was referring to blasting the drain with the hose to clean it out before proceeding to use the pvc to funnel some liquid chlorine into it.
My fingers get ahead of my brain sometimes- I should have listed the recommendations in that order.

We’ve seen some folks with “alternative media” really experience some recurring issues so glad to know you’re using sand.

 

[doc19]

I guess if the pvc was dirty you would wanna spray it out but I was referring to blasting the drain with the hose to clean it out before proceeding to use the pvc to funnel some liquid chlorine into it.
My fingers get ahead of my brain sometimes- I should have listed the recommendations in that order.

We’ve seen some folks with “alternative media” really experience some recurring issues so glad to know you’re using sand.

got it! Weird question, how would I blast the drain with the hose? We have a 9 foot deep end. Would I just drop the hose into the deep and and try to get it positioned on top of the drain?

 

[Mdragger88]

got it! Weird question, how would I blast the drain with the hose? We have a 9 foot deep end. Would I just drop the hose into the deep and and try to get it positioned on top of the drain?

Maybe zip tie it or tape it to the pvc (if you get a piece - they are sold in 10ft sticks and you can add a short piece to that too) or your pool pole to help guide it.
I would secure a rag around any sharp edges to protect your liner.