Mustard Algae Questions and FC Dissipation w/o heavy sun

cjs

LifeTime Supporter
Jul 13, 2014
32
Cypress, TX
I have a very minor mustard algae presence in my pool. What I mean by this is that it is mostly clear, but there are a few spots, namely on the plaster right under the rock water fall, on tile inside skimmer gutters, along some grout corners on the water line tile, and in the spa which has a constant spill over. I don't lose much FC day-to-day, and I simply brush the pool to get rid of it. It comes back over the course of a week or 2 if I don't brush regularly.

Here are my questions:
1) If I truly get rid of the Algae using the Mustard Shock levels and maintain that until no FC loss over night, will it stay gone as long as the FC level does not drop back down.

or

2) Will this small amount of algae regularly appear even in a perfectly maintained pool when conditions are ripe and things like brushing are not done frequently.

Then...

3) If I do in fact need to get rid of this algae once and for all, my plan has been to wait until after the summer sun dies down a bit and I get more shade on the pool. My thinking is that it's easier to maintain the high FC level when I'm not losing 4-5 ppm each day to the sun alone. My concern, however, is how easily will I get my level back down to a point where I can use the pool and hot tub if it's the winter month and my FC loss each day is minimal with all the algae gone? In other words, will I be stuck with FC at 24 from November through March without the sun to burn it off?

Thanks for your help,
Craig
 

PoolGuyNJ

TFP Expert
May 20, 2007
3,192
South Central NJ
Simple brushing just spreads mustard. Shock the heck out of it. It's tough to kill. Use bleach or 12% liquid to get the level up. Turn off the waterfall for now.

What are your current chem levels? You seem to be losing a lot of FC per day. Pool specs would be helpful too.

Scott
 

cjs

LifeTime Supporter
Jul 13, 2014
32
Cypress, TX
My pool specs are in my signature. As for high fc loss...welcome to pool maintenance in south Texas in August! My over night tests are fine.

I do use bleach, my levels are maintained per the pool calculator.

My questions are: can you ever completely get rid of algae and how long does it take to get the fc back down to swim levels without the sun or algae to deplete it?
 

dmanb2b

TFP Expert
LifeTime Supporter
Apr 4, 2009
3,734
NY
cjs said:
My pool specs are in my signature. As for high fc loss...welcome to pool maintenance in south Texas in August! My over night tests are fine.

I do use bleach, my levels are maintained per the pool calculator.

My questions are: can you ever completely get rid of algae and how long does it take to get the fc back down to swim levels without the sun or algae to deplete it?

Well, you must have slipped at some point on maintaining those FC levels, otherwise you wouldn't be dealing with MA :goodjob: You've been a part of the TFP community long enough to know that it's good practice to post a full set of test results, so that we can help you better. Now that you have MA, at least it's not spreading rapidly, but you will need to shock at MA levels to rid yourself of the bloom.

When you say your overnight FC test is fine, you mean you lose no FC overnight, correct? I am also assuming, you are not adding chlorine overnight or turning on a SWG during the test?

As for your specific questions... regarding shocking and how long after you can swim, I believe you already have the answer since you know you are losing 4-5ppm per day due to sunlight and most folks are comfortable swimming under shock level. Given you have not provided a CYA reading, there is no way for me to estimate how long it will take other than if you have no overnight FC loss now, you should continue to see a loss of 4-5ppm FC per day when at MA Shock level. You can swim when you are below shock level.

Lastly, yes it is possible to rid you're pool of an alage bloom, and maintaining your FC levels will minimize the risk of further blooms...algae spores will always continue to be introduced to your pool, but you're FC is what keeps it from growing.
 

PoolGuyNJ

TFP Expert
May 20, 2007
3,192
South Central NJ
Simple miscommunication. To me a waterfall is a waterfall, not a spa's spill way.

Specs don't show in full editor.

Full Tx sun or not, that seems like a lot. What are your current chem levels?

Scott
 

cjs

LifeTime Supporter
Jul 13, 2014
32
Cypress, TX
Cya 50
Fc 5
Tc 5
Ph 7.5
Ta 80

6% bleach to chlorinate. I don't have borax in the pool because of pet concerns.

I found TFP when I first had a MA problem. I had high cya and didn't maintain he proper levels. That was all resolved long ago, I've just never taken the step to fully shock away the MA, which is what I'm looking to do next.

I have been around long enough to understand all of this. My questions are theoretical in nature, I'm not expecting a precise answer. My pool is perfectly balanced per the pool calculator, which has allowed me to keep the algae in check. So...

1). Can you ever really fully get rid of algae, and
2). How long does it take for FC to drop from 24 to 5 without algae or sun to deplete it...with CYA at 50?
 

cjs

LifeTime Supporter
Jul 13, 2014
32
Cypress, TX
Waterfall clarification.

I have both a spillover and weeping wall. The waterfall is off 95% of the time. Generally speaking though, why did you say to turn that off? Does that increase FC loss or something?
 

dmanb2b

TFP Expert
LifeTime Supporter
Apr 4, 2009
3,734
NY
Hi CJS...I think I answered your question above. If you lose 4-5ppm every day, you should be down to 5ppm in about 4 days. You can never get rid of all algae spores, but you can eliminate the living ones in your pool water by shocking and then maintaining FC at 5-6 ppm should keep them from blooming again.

Also just a note that the TFP suggested levels are in fact just suggestions. Since you live in a warmer climate, have had MA, etc, there is nothing wrong with maintaining an FC target level of 6-7 (CYA @ 50) to provide added insurance :goodjob:
Also, don;t forget to toss in all pool toys, equipment etc in the watre, while shocking and brush viguorsly.

Good luck!
 

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