OH NO! Is it dirt or MUSTARD ALGAE

J_L_D

Active member
Jul 1, 2010
39
Madison, MS
I've had the pool about 2 months. It took 4 weeks, but with the help of this board I turned the world's worst swamp into a Sparkling Oasis. Now, starting about 2 weeks ago, I start seeing what looks like sand in liner joints and depressions. But it's darker than sand, sort of brownish and maybe little yellowish. So I vacuum, brush, etc...it never goes away, but slowly becomes more prevalent. Then one day a week or so ago I see discoloration/sheeting on sloped part of deep end, and where walls meet in those slopes and and where slopes meet bottom. This stuff is less 'sandy' and puffs into a cloud when I brush it. It sort of goes away, but not totally. Then yesterday there is more of it. So I brush entire pool and run pump all night, add 1 jug 182 oz bleach.

Did drop test this morning and had 5.5 FC and 0.0 CC, but the junk is still there, just less of it. At first I thought filter was leaking dirt/sand back through but now I think it could be mustard.

Here are some specs from when I originally tested everything about a month ago (and it was crystal clear), except I've changed PH to what it is currently (was 7.2 at that time)

PH = 7.5
FC = 5.5
CC = 00
TA = 100
CH = 30-40
CYA = 25

I think I might be at fault, as I've tried to keep FC at 2-4, but sometimes it goes to 1, or even .5 or less (only one time). After I got everything clean, I quit running the pump 24/7 and do it 8-12 hours a day. I usually add 1/3 to 1/2 jug of 182oz bleach per day. That should seem like enough to me, but maybe I should be using more.

Do you think it's mustard? Should I start shocking hard and raise it 17? Wouldn't I have some CC if it was mustard?

Oh, and I was going to add 45 lbs. of Pro Team Supreme Plus - it should help prevent this issue - but should I wait until it stays clean for several days first, or would it help resolve it.

I'm thinking about calling home and having wife dump 3 jugs in then brush it this evening and do the overnight test, just in case it is mustard
Thanks.

I forgot to mention - it's been insanely hot here in the Deep South - upper 90's and triple digits - pool feels like bath water - maybe that's good for the algae but not sure.
 

jasonknox

Platinum Supporter
May 4, 2010
300
SW Georgia
Re: OH NO! Is it dirt of MUSTARD ALGAE

I am not sure what it would be either. I have had similar problems and was told that the fine particles would no be filtered by the sand filter and to vacumn to waste. I did this and things got better. If it is mustard algae I would guess you would need to kill it first before vacumning? Personally I keep my pool a little higher in FC just for a cushion, in case I forget to add bleach on time.
 

geekgranny

LifeTime Supporter
Aug 20, 2009
1,358
North Central Texas
Re: OH NO! Is it dirt of MUSTARD ALGAE

jasonknox said:
I am not sure what it would be either. I have had similar problems and was told that the fine particles would no be filtered by the sand filter and to vacumn to waste. I did this and things got better. If it is mustard algae I would guess you would need to kill it first before vacumning? Personally I keep my pool a little higher in FC just for a cushion, in case I forget to add bleach on time.
Same here with the chlorine. I can pretty much add chlorine every other day, unless bather load increases, and take it to the top of my range or a little over. That does offer a little cushion in case I miss adding it one night. If so I test early next morning and bump it up to the top again. BTW..... I add bleach, at any time of day, if it's getting too low. Better to have burn off than risk mustard algae.

gg=alice
 

Mona

LifeTime Supporter
May 23, 2007
91
SE Minnesota
Does it always come back in the exact spot, or will it shift to other spots? If you feel it is it slickery or gritty? My first thought would be just dirt especially since you aren't having cc issues. Dirt does have a tendency to collect more in the wrinkles and crevices. Get some skimmer socks. I found that the dirt is so fine it just goes through the filter and doesn't all get trapped. Using skimmer socks it get caught in the sock before it hits the filter. I just rinse the sock out when I turn of the pump for the night.
 

frustratedpoolmom

TFP Expert
LifeTime Supporter
In The Industry
May 20, 2007
12,179
SWSuburban Chicago, IL
Are you saying you had no overnight loss? you only posted the morning result.

you should increase your CYA level - that will help prevent your FC from dropping too low during the day. No reason to wait to add the borates.

If you had no overnight loss it's probably not mustard algae, but that doesn't mean it's not dead algae... it could be you are one step ahead of something lurking in there.

0 CCs is not necessarily an indication of anything....
 

J_L_D

Active member
Jul 1, 2010
39
Madison, MS
Thanks for trying to help me!

First it was gritty AND puffy, and now more of the puffy stuff - like slicks on the slopes of this vinyl liner pool.
Yes - I put a jug in last night and brushed (always 182oz)... same funk this morning.
had 5.5 FC and 0 CC (I use TF-100 test kit)

came home tonight and still there - maybe more - where sloped walls meet each other and and bottom/slope.
Check FC/PH and have 5.5 and 7.7 (this is much more than ususual 7.3-7.4_
Add 2 jugs bleach
Go back to HD and buy stabilizer and PH down
Add 3lbs dry acid and 2.5 additional jugs bleach (should be close to 17 at this point)
Brush entire pool.

I will wait til sun goes down, do drop test, get another one early tomorrow and post.
This is the only time I've 'shocked' since I got it clear.
 

J_L_D

Active member
Jul 1, 2010
39
Madison, MS
Testing did not work so well.

10:30 pm. I put the 10ml of water in, then added scoop of powder 870?... nothing... added a 2nd scoop and it turned pink.
Added the 871 drops --- got to about 39 drops and it was almost clear but not like when I have done it before with low chlorine and it turned completely clear. Kept adding drops but it never got any more clear so I stopped at 45 drops.
So FC is about 20?
Added the 5 drops of 871 and could not tell any difference in the 'almost' clear container. So 0.0 CC?
 

J_L_D

Active member
Jul 1, 2010
39
Madison, MS
More chemistry this morning.
Visual inspection of pool showed at least 50% reduction in the visible algae. Brushed the pool fairly thoroughly and as before, flat areas in shallow end do puff up a bit with the stuff, in places where it's not readily visible.

Ran some tests.
For FC - had same issue as last night, the scoop of powder did not change the color, so I added another 1/2 scoop and it turned pink.
Add the drops and as before, I reached a point where it was 'almost' clear, but adding additional drops did not make it more clear. But this time that number was more like 34 instead of 39. Added 5 drops of 871 and could not tell any difference in the color. I also ran a CYA test, which indicated a level of 55. I didn't know if the elevated chlorine level affected the test. I bought the stabilizer but didn't add it since it went from 25 to 55 - I had used some pucks but not many, maybe 10. I ran PH test and it looked to be about 7.8. I think it could be reading higher due to the high chlorine level because yesterday I read 7.8 when FC was at 5.5, but when I read PH after bringing FC up it read over 8.2, or so it looked. I presume the 3 lbs of acid dropped it back to 7.8, even with the high FC, and that once FC drops back to normal, the PH will fall back also - can anyone comment on that?

So:

FC - 17
CC - 0
PH - 7.8
CYA - 55
TA - not checked - was 100
CH - not checked - was 35

I added another jug of bleach so that should bring it back up to 20 and maybe keep it at super-shock while sun brings it down today.

A question maybe better for chem-201 forum, but does it take any more chlorine to keep it between 3-6 than it does 1-4? That is, does it burn off faster at higher levels?

The other thing - Did the high FC change CYA from 25 to 55? Does this change my shock level for FC?

Thanks
 

frustratedpoolmom

TFP Expert
LifeTime Supporter
In The Industry
May 20, 2007
12,179
SWSuburban Chicago, IL
FC over 10 will make the PH read a false-high. You should always adjust PH first, if it's above 7.8, before shocking to get an accurate adjustment.

You should use Muratic Acid for PH, dry acid adds sulphates to the pool.

high chlorine levels will not affect CYA. How you perform the test will. Always test outdoors, in sunlight, with your back to the sun to shade your view tube. Performing the test under different circumstances can affect the result.

When your CYA is higher, and the corresponding FC level is higher, you will actually lose LESS FC during the day.

You are getting some kind of interference while performing the overnight test. I suggest repeating it tonight without adding any additional bleach this evening. It's not clear but it seems like you did have a loss and you may be fighting a mustard-algae type of some sort.

Don't add any more chlorine today. Allow the levels to come down to a normal range. Retest the PH and adjust as needed, repeat the CYA test outdoors in direct sunlight with your back to the sun. After sunset test the FC and CC and then repeat in the morning; post back your results.
 

kal2002

LifeTime Supporter
Jul 4, 2010
235
northern California
J_L_D said:
For FC - had same issue as last night, the scoop of powder did not change the color, so I added another 1/2 scoop and it turned pink.
This happened to me too and I am in the middle of shocking mustard algae with FC at 24.

J_L_D said:
I ran PH test and it looked to be about 7.8. I think it could be reading higher due to the high chlorine level because yesterday I read 7.8 when FC was at 5.5, but when I read PH after bringing FC up it read over 8.2, or so it looked.
I also ran the pH test and had the same experience. Is the pH test accurate when FC is super high?


J_L_D said:
A question maybe better for chem-201 forum, but does it take any more chlorine to keep it between 3-6 than it does 1-4? That is, does it burn off faster at higher levels?
I wonder about that also. pH was 24.5 yesterday morning and it was 16 in the evening.
 

frustratedpoolmom

TFP Expert
LifeTime Supporter
In The Industry
May 20, 2007
12,179
SWSuburban Chicago, IL
As stated above, the PH test is not accurate if your FC is above 10.

You have a typo in your last sentence :)
That would be a normal drop when shocking - you will still lose roughly 50% of your chlorine during the day, so at shock levels a drop of 24.5 to 16 during sunlight would be normal. We always recommend the overnight test for determining organic consumption because it takes sunlight out of the equasion.
 

J_L_D

Active member
Jul 1, 2010
39
Madison, MS
OK. Thanks. Yes I think I'm fighting the mustard monster. My question on Chlorine usage - I know as you say that it will hold better with higher CYA level - but what I was trying to ask is assuming constant CYA level, does it take more Chlorine to hold between 3-6 than it does between 1-4? Or once I get it there will the demand be the same as 1-4.

On the PH - I did test before shocking - FC was 5.5 and PH was 7.8. That's why I added the acid. I'm hoping once FC gets back down to 5, PH will be around 7.4 or so. I will switch to Muriatic acid - if I can find it.

On the CYA - you are right - the conditions were not the same but I thought it was close enough. The last time I checked was full sun with my back to it. This morning the sun was not directly on my back, nor was it full. I'll check again this afternoon.

OK - I'll add no more bleach today - check PH, FC, CC tonight and post results. Then run same tests tomorrow morning and post.

Oh - any tips on making sure my FC test is accurate at these levels - reference having to add 2 scoops powder and that it never 'fully' turned clear.
 

frustratedpoolmom

TFP Expert
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In The Industry
May 20, 2007
12,179
SWSuburban Chicago, IL
With a higher CYA level your overall usage will actually be somewhat less. This varies obviously from pool to pool but can be as much as 1-1.5 ppm less.

2 scoops was the right thing to do - I suspect your chlorine level was just higher and you may have stopped the drops too soon - or there was intereference from CCs but the confusing part was the second reagent didn't change the color. In any event testing tonight with a lower FC should eliminate any interference. Any chance you have a magnetic stirrer? They are very helpful when counting drops at high levels. (kinda fun and handy in a pool-nerdy kinda way...LOL)

Check Home Depot or Lowes or hardware stores for muratic acid - ask someone but it may be in their paint department.
 

banjomarsh

Member
Aug 4, 2010
8
Pekin, Illinois
This is the exact problem that I have been having 2or 3 times a season for the last 2 years. I just joined this board to learn. I found this site while trying to find a cheaper source of the product REVIVE!. This product works to clear this up for me,( I just got done with a treatment, now water sparkling clear again. I blame my well water, high in "clear water iron". I hope to learn how to prevent this from this forum.
 

frustratedpoolmom

TFP Expert
LifeTime Supporter
In The Industry
May 20, 2007
12,179
SWSuburban Chicago, IL
Revive is just floc. It does nothing to kill algae.

Edit: Banjomarsh - If Revive is helping your situation - what you are seeing is not mustard algae at all but dirt/dust/pollen and the floc just helps it clump together so it can be vacumed/filtered out easier.
 

jasonknox

Platinum Supporter
May 4, 2010
300
SW Georgia
I agree with FPM the magnetic stirrer is a must. I actually got higher numbers when hand swirling but had algea. I adjusted my FC based on the numbers from my magnetic stirrer which were lower and my pool has been clear since. I can only guess that I was not swirling vigorously enough?

Do you have good water circulation in the bottom of your pool where the algea is forming. If you do not the algea in this areas could be depleting of FC in the surrounding water while other parts of your pool where you get your test sample may have better circulation and thus show chlorine.

I see you are still debating an automatic cleaner. If it does turn out to be a stagnate water issue a pressure side cleaner like the polaris would go along way to ensuring that that water on the sides and bottom of your pool is moved about. Before I purchased my magnetic stirrer I thought this was the issue I had and was looking at a cleaner to help with what I thought was a stagnate water issue. The magnetic stirrer was alot cheaper than a cleaner.
 

J_L_D

Active member
Jul 1, 2010
39
Madison, MS
OK.
So my program appears to be working. Mustard Algae might be resistant to low levels of chlorine, but it cries like a little girl when you bump FC up to 20 or more (with CYA under 30 in this case, last I 'accurately' checked).
Visual inspection - 98% gone
Brush the entire pool - yes, I see some clouds poof up in places, but still WAY less than before.
Testing:
FC = 11.5
CC = 0.0
PH = 7.5
I was unable to do a new "sun out shining on back" CYA test due to the weather.

Will see if FC holds and post back tomorrow a.m.

ps. It's OK to re-open the pool for tomorrow, no?

Thanks.
 

frustratedpoolmom

TFP Expert
LifeTime Supporter
In The Industry
May 20, 2007
12,179
SWSuburban Chicago, IL
yes. As long as your water is clear and your FC is below shock level it's safe for swimming. If the FC doesn't hold, you can resume shocking tomorrow evening.
I hear ya on the weather - its been lousy here all week... Had to drain 5 inches of water off my pool today.
 

J_L_D

Active member
Jul 1, 2010
39
Madison, MS
Thanks FPM - I think we have some different weather issues... It's been insanely hot here ---upper 90's into triple digits, regularly, for a few weeks. It got cloudy today and we might have had a little rain, which cooled things down, for a minute. I stuck my hose in the pool for 2 hours and still need to ADD 5" of water. It feels like a hot tub in there! Probably, the heat, and my lack of keeping FC high enough caused the MA outbreak. I let it go longer than I should have, cuz I didn't know what it was, but I caught it in time and used the advise from this board -- Hit it Hard, Fast and Heavy with chlorine - it does work.
 

J_L_D

Active member
Jul 1, 2010
39
Madison, MS
Morning Numbers:

FC: 10.5
CC: 0.5 (best I can tell)
PH: 7.5

Still having a little difficulty with the drop test. Added the 5 drops to check for CC and it appeared to slightly change from clear - so added 1 drop then another of the first reagent - it did seem to turn back to more clear - but couldn't tell difference in adding one drop or 2. It didn't really turn 'pink' with the 5 drops, just seemed to add a little color to it.

Visible - not much left to be seen. The normal crevices where I find grass, sand, debris had a small amount - but when I brushed it I didn't see any of the cloud puffs, so I think it's just sand/dirt. I'll try to vacuum it up tonight and look for it again tomorrow.

I plan to continue to let the Free Chlorine burn off to around 4 and try to keep it there. Will verify CYA once again in sunlight and use Pool Calulator for FC levels. If under 30, I'll probably use some Tri-Chlor pucks for a few days to try to bring it up a bit. Taking sample to pool store today at lunch and buying 45lb. bucket Proteam Supreme Plus - Any comments on that? It IS proven to be safe and effective - right? I will post the results from pool store - I want them to check for borates just in case someone had already added them in a previous incarnation of the restored pool.

Thanks and let me know what I'm missing. The one thing I'm not sure is how much I should raise Cyanuric Acid level. I actually bought a 5 lb jug at Home Depot but thought I'd return it and get something smaller (that was all they had), or just use the pucks I already have for a week or two. But being in full sun all day maybe it needs to be well above 30?
 
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