Fighting Mustard Algae yet again, am I on the right track?

Richard, believe me, I feel your pain! I only fought my battle with MA for 2 weeks and I was ready to fill in my pool too. I'm telling you, phosphates could be the answer and that would explain why your neighbor's pools don't have the same problems. Phosphates can enter the water from many sources: swimmer wastes, laundry detergent in swimming suites, and the other methods mentioned above (fertilizers, fill water, etc).

I have read that MA can develop resistance to chlorine and I think that was part of my problem and may be part of your problem too. At least get your water tested for phosphates and if you have a very high level (mine was over 1000 ppb) then I think that is your problem.

I tried Yellow Out and it did not work for me. Phosphate remover is now part of my maintenance routine and I have not had another breakout of MA in 2 years.
 
High phosphate levels are not a problem at all. I have phosphates in my tap water. My phosphate levels in the pool are over 4,000 just at the moment and my pool is crystal clear and has been for quite some time without any problems. Pool stores push phosphate remover way too frequently. It can help is specific situations but the great majority of time it is a complete waste of money and can cause problems of it's own.

Mustard algae does require higher FC levels to kill permanently than regular algae, but it does not develop resistance to chlorine. It has the level of resistance that it has, which does not change over time.
 
I have 2000-3000 ppb phosphates in my pool and control algae growth via chlorine alone. I will say that a pool with such rich nutrients is fairly unforgiving, but since I've added 50 ppm Borates this year it seems to be less so (but I managed for 5 years just fine so long as I maintained a proper FC level). We'll see after I experiment later this season letting the chlorine go to zero and seeing how long it takes for the pool to turn dull.

As for whether to use any supplemental algaecide or phosphate remover, that is purely a personal choice. Most pool owners at The Pool Forum and at this site who had mustard/yellow algae were able to get rid of it through higher level FC shocking including getting behind light niches, pool poles etc. and keeping the chlorine high for 2 days beyond visible algae or FC overnight drop. In another case, the person ended up just keeping their normal FC higher at 15% of the CYA level (for a manually dosed pool; for an SWG pool, an FC that is 10% of the CYA level might be sufficient). Clearly, if you don't get rid of it then you will be forced into some form of algae-control maintenance products (or a higher FC level) at extra cost.

Richard
 
Alright, here we go! Time to wipe this Mustard Algae out for good.

2200 tonight test results and (goal)
pH - 8.0 (7.0 -7.2)
TA - 180 (80)
CYA - 70 (80)
FC - 2.0 (39 - Mustard Algae shock per Pool Calculator)
CC - 0

Added 2 gallons of Muriatic Acid, waited 45 minutes (pump running, of course)

pH down to 7.0
I'm not gonna try to raise the CYA any further until after shocking due to the increased Chlorine demand at a higher CYA level.

Continuing to step #2
Shock the Bejeezus out of it!
15 - 182oz bottles of 6% bleach
 
Okay...

I stopped after adding only 13 bottles of bleach because all of the other times I've tried to shock with this method I've overshot it a bit. This time was no exception!
One hour after shocking and a thorough brushing of the pool...

FC - 45

Also, aeration to lower TA has begun.

I'm going to bed but I'll check it again before daylight.

G'night all and thanks again.
 
Thanks, Jason. My equipment is in the pool and the toys are getting tossed out. I'm not doing all this work to have it undone by a $5 inflatable raft! I'm brushing everything. One area I haven't brushed in the past (but did this morning) are the skimmer baskets and that whole area.

Here's what's happenin' this morning...
0620

FC-39

added 2 (182 oz) bottles of 6% bleach
Brushed entire pool again

0730

FC- 49

0800

FC-48

Gotta run the kids to Summer Camp. Will check again when I get back.
 
There is no way you can avoid problems when your FC drops to 2 and your CYA is 70-80. If you are too busy to keep FC at a more reasonable level, maybe you can spend a few $ a week (neighborhood kid who wants a few $$ over the summer) to have someone come regularly and add CL and then you can relax and play in the garage.
 

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OK, gang let me lay the latest numbers on you and see what you think.

Aerating this whole time, BTW.

To recap, yesterday morning it was
0620
FC-39 (Based on my 70 CYA this was borderline for Mustard Algae Shock per the Pool Calculator)

I added two bottles of bleach and brushed the pool.

0700
FC- 49

0800
FC-48

Had to leave for most of the day but returned and tested at...
1630
FC-30 (<---HUGE DROP)

Added 2 bottles of bleach (all I had on hand) and went to the store for more bleach

1730
FC-36

Added 3 more bottles of bleach and left for the evening.

Now it's 0100 and the FC is...

FC - 37 (WTH?)

Curious as to why my FC won't go any higher?

This time I ran a CYA out of curiosity and it's dropped to 55!

What happened to my CYA?
A lower CYA should help my shock efforts (Pool Calculator says to shoot for a 32 at 55CYA)

What's going on here?
 
I wouldn't worry about the CYA level test when the chlorine is high. People rarely test it after getting the FC to high shock levels and there are a few possibilities here: 1) high FC interfering with the CYA test having it read artificially low, 2) some oxidation of CYA by chlorine (unlikely to occur that quickly, however), 3) test variation. I read somewhere recently about #1 where some suggested adding chlorine neutralizer to the sample prior to adding the CYA reagent. You'd have to add around 8 or so drops (of sodium thiosulfate) which is reagent R-0007. Personally, I don't think it's worth it, but if you've got plenty of CYA reagent on hand and want to do the test again but first adding the chlorine neutralizer (and mixing), then let us know what you get.
 
Shelley,

You make a good point regarding always maintaining at least a minimum FC level appropriate to the CYA level or else algae can grow faster than chlorine can kill it. In the case of yellow/mustard algae, however, it usually takes higher chlorine levels to keep it from growing so when that is impractical a hard shock to thoroughly get rid of it can be a decent alternative. So yes, we don't really have any violation of the basic principle or chlorine/CYA chart here and SinistrV6 could probably have kept the algae away through a more consistently higher minimum FC.

SinistrV6,

There is no saturation point. You could dilute your water sample with tap water to get readings using less reagent and your accuracy at such high levels doesn't have to be within 0.5 ppm anyway. If you are losing FC overnight then the chlorine may be killing algae, which is a good thing. You'll want to sustain the high level until there is no visible algae anywhere (not even in niches) and the overnight FC loss gets lower (perhaps not 1 ppm FC drop, but even 2 ppm FC drop could be OK given the higher FC levels, especially if you dilute which has less accuracy) and this situation persists for at least 2 days/nights.

Richard
 
Time for an update...

Well it's been just over 2 weeks since my last post. FC was still very high at that point (20+) and the SWG was OFF. We had a party on 6/14 with lots of swimmers.
Two days later, I sampled the water and turned the SWG back on.
6/16 Results:

FC - 7
CC - .5
TC - 7.5
pH - 7.8
TA - 150
CYA - 70

Aeration continuing 10 hrs/day I have added acid to try and lower pH (in efforts to lower TA) but haven't had much luck.

6/18

Added 2# of CYA to try and reach a CYA of 80
Increased circulation time to 12 hrs (0800-2000)

6/19

FC- 4 (no CC)
pH - 7.8
CYA - 80
Salinity - 3800ppm (Just checked out of curiosity)

Added -1 gallon Muriatic Acid
1 gallon Bleach

6/22
pH - 7.6
FC - 4
CC - .5
TC - 4.5
TA - 140

Put a restrictive "eyeball" in the socket where my Polaris "robot" goes to increase pressure to the other eyes when the Polaris isn't in the pool. Hopefully, that'll help improve circulation in the "dead zones".

6/29
Well a week has gone by since my last testing and the FC has dropped very low. I guess the SWG just isnt capable of keeping a decent FC level in the pool. Is this normal or an indication that it doesn't work properly? We've had ZERO rain for the last 2 weeks and temps in the 100 degree range. Evaporation is high and I've had to add water about 3 times in that period. Is that negating the efforts of the SWG? CYA level has been stable.

FC - 1.5 (no CC)
pH - 8.2
TA - 160
CYA - 80

BTW, SWG is (and always has been) set at 100%. I know that's not ideal, but it's the only way I can keep any sort of FC level at all. Pool is currently bright and clear.
 
frustratedpoolmom said:
Yes, I've been wondering where ya been, how it was going.

What about an overnight loss test? I would rule out nascent algae, if it holds overnight then its the unit itself, can't keep up or is not functioning properly.

Haven't done it since the Mustard Algae shock, but it held a FC of 4 for several days. I honestly don't think there is any algae anywhere in the system. I do have bugs and grass in the skimmers almost daily but I've started cleaning them every day.

Is there any way to know if the SWG is working? It says it is, but who really knows?
 
An overnight FC loss test, with the SWG turned off, is the only way to rule out organics overwhelming the unit.

It did hold at 4, but something changed. An overnight FC loss test can rule out organics, and pinpoint the unit itself.
 

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