Mustard Algae Reoccurence

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L

Lawtyger

Well-known member
Mar 11, 2016
121
Tampa, Florida
We have had a mustard algae bloom a couple times in the last six months. I am not 100% sure why it keeps reoccurring, I have stayed on my pH consistently keeping it from going above 7.8 dropping it back down to 7.4 routinely. FC is on average 5.0 and CYA is at 45. The pool looks pretty clear, but when I brush the bottom I do see a slight half up though I suppose algae. It's when I open the filter to clean it and wash it out but I definitely see the greenish algae has developed in the filter.

I just started the shock process I've used in the past and currently have the FC up to 16. Should I be pushing the FC up even higher?

Just found the SLAM link and will follow that (Pool School - SLAM - Shock Level And Maintain). Any other thoughts are still welcome.
 
Definitely follow the SLAM page to the letter. That's #1. Make sure to lower pH before increasing FC though. You want pH about 7.2 before starting. Then, based on a CYA of 50, increase FC to "20" and the key ..... MAINTAIN it until you pass all 3 SLAM criteria. It's important to also brush all pool surfaces daily and clean filter if pressure increases by 25% during this process. The SLAM page should do you well. Good luck.
 
Update - FC stayed at 24 overnight. Only 12 hours into the SLAM though. As I mentioned above, the water was still really clear in the pool but upon cleaning the filter I saw that I recognized to be algae. I will continue to run the pool pump for another 12 hours. Also just got done cleaning the filter and scrubing down all the walls of the pool.

I'm guessing the answer may be no, but if I were to put the automatic vacuum in the pool now does that still count as the pool "constantly circulating"?

I plan to do a manual vacuum tomorrow after work and then another filter clean out.
 
You certainly can use your automatic vacuum. If it's a suction/pressure actuated device, then your pump would of course be running so that's good. If it's an electronic operated robot-type cleaner, that's not the same, so you would want your pump at least on low. Hope that helps.
 
L,

The suspect reason that you continue to get Algae is that you are not keeping your FC high enough.. You say your "average" FC level is 5 ppm. Well, your very minimum FC should be 3 or 4 and your goal or average should be 7 or above. I suspect that you are letting you FC drop well below 3 ppm.

So, after your SLAM, I suggest you try and keep your FC a little on the high side.

Thanks for posting and good luck with your SLAM,

Jim R.
 
Jimrahbe said:
L,

The suspect reason that you continue to get Algae is that you are not keeping your FC high enough.. You say your "average" FC level is 5 ppm. Well, your very minimum FC should be 3 or 4 and your goal or average should be 7 or above. I suspect that you are letting you FC drop well below 3 ppm.
Click to expand...

Thanks Jim, actually FC amount is one of the tests I feels really comfortable with (unlike reading CYA for example). I check my FC three or four times a week along with PH and in the last couple months the lowest my FC got was 4.5 and that was once. Looking back at my results which I put in an app, more often than not my FC has been 5 or 5.5 (or higher since I let the FC level go down on its own after the last shock. Of course, that isn't maintaining it at a 7 like you suggest either.

All that said, I do feel like in the past I may not have gotten the FC to the level I needed to for my CYA level when doing a slam/shock. The first time the algae came I didn't realize it was algae and thought it was just dirt was got on the pool surface after the pavor guys came to address some sinking pavers and laminars.- new pool owner still, lol. When the pool builder came they said it was algae, not dirt, and to throw in 2 and 1/2 gallons of liquid bleach. I realize now that them just telling me to do that: a) did not take into account my CYA level, and b) wasn't enough to get the FC level for my pool's CYA level.

Also, I must admit that the CYA test is one that I find difficult. I always have trouble telling when I can't see the dot for sure. I've taken water test to the stores (knowing they aren't reliable) just to get an idea and when I am reading 45 or 50 the store's results are much higher like 80 to 100. But the fact of the matter is, I am definitely not reading levels that high and arguable can see the dot when do my test and get 50.
 
L,

Sorry, my comments were based upon my experience with what "most" people do in the way of testing. :p It certainly does not appear that your testing routine falls in that category..

I too have a hard time with the CYA test, but one of the things that helped was I purchased the CYA "50 ppm Standard". Knowing what the exact result was supposed to be, helped me adjust my testing so that it became more accurate. The most important change for me was to just glance at the tube and not stare at it. If I stare at it, I swear I could see the black dot threw a sheet of lead... :cool:

Thanks for the feedback,

Jim R.
 

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Jimrahbe said:
. . . but one of the things that helped was I purchased the CYA "50 ppm Standard". Knowing what the exact result was supposed to be, helped me adjust my testing so that it became more accurate.
Click to expand...

I hadn't heard of this but doing some searches it sounds like a solution I can buy. I will definitely look into this further.

Jimrahbe said:
The most important change for me was to just glance at the tube and not stare at it. If I stare at it, I swear I could see the black dot threw a sheet of lead... :cool:
Click to expand...

This IS me. I think I am just staring at the solution too long to try to see the dot. I will definitely try to just glance at it and not stare at it in the future. I will also look more into the CYA 50 ppm standard as well.
 
Lawtyger said:
I hadn't heard of this but doing some searches it sounds like a solution I can buy. I will definitely look into this further.



This IS me. I think I am just staring at the solution too long to try to see the dot. I will definitely try to just glance at it and not stare at it in the future. I will also look more into the CYA 50 ppm standard as well.
Click to expand...
Are you doing the CYA test outdoors on a bright sunny day, with your back to the sun?

I like to fill to a line then look for the black dot. If I still see the dot, I fill to the next line and look again. I do this until I do not see the dot at first glance.

Also, you can pour the sample back into the mixing bottle and repeat the test using the same sample. I usually do this 2-3 times to make sure I am comfortable with the results.
 
domct203 said:
Are you doing the CYA test outdoors on a bright sunny day, with your back to the sun?

I like to fill to a line then look for the black dot. If I still see the dot, I fill to the next line and look again. I do this until I do not see the dot at first glance.
Click to expand...

Yes for the most part. I definitely turn my back to the sun but time and amount of sun does obviously change depending on weather. I've previously watched some videos on testing CYA and read all about the testing process (on Taylor's site - just reread it this morning actually) with pictures of examples what the dot should look like. Let me be clear, I don't feel uncomfortable with the test. . . I just feel that while I have gotten the FC, PH, ALK tests comfortably under my belt after just under a year of pool ownership, the CYA I still feel like I'm wondering if I'm spot on or 10 ppm off either way when reading it.

A lot of my lack of confidence level probably relates back to taking the sample to the local pool store in the past and believing, since they should be so experienced, that there test results were more accurate. There were times I'd read a 40 and they'd be telling me I had 90. On the flip side, there was one time in the beginning my FC level was not maintaining and based on their numbers I could not figure things out because I was sitting there with 0 FC and CYA of 100 - according to the pool store - when reality the boy at the counter should have typed 10 CYA. So, in the middle of the Florida summer I had zero to no CYA instead of the 100 the pool store said and then it made sense why my SWG was not generating enough FC.

In a nutshell, I think if I just get the CYA test down pat I'll be much better off. And, the suggestions I've gotten in this thread will help with that.
 
SLAM is officially complete. FC at 21 and will let it go down on its own.

The real test will be whether this mustard algae pops back up a mont from now.

My CYA is currently around 50 so I will raise that to 70. What should I maintain my FC at consistently? It sounds like 5 but I was maintaining FC 5 at 50 CYA and the algae crept up. Maybe it just never truly killed it because on the previous shock attempt puts my FC level never got high enough to be effective given my CYA level at the time not being taken into consideration???
 
Hi Lawtyger
For ongoing maintenance refer to the chlorine / cya chart here: Chlorine/CYA CHART
For 45 CYA round up to 50. So target 8FC and dont let it drop below 4

However if mustard algae is a concern then you need to do an extra step once you pass your slam
You raise your FC levels to mustard levels for 24 hours and then let the FC drop
Mustard level FC for 50CYA is 30
If you have already raised your CYA to 70 then your mustard FC level is 40

Also FYI the CYA test accuracy is plus/minus 10, so dont sweat it too much
In saying that the CYA standard helped me a lot with that test

HTH
 
Caco said:
However if mustard algae is a concern then you need to do an extra step once you pass your slam

You raise your FC levels to mustard levels for 24 hours and then let the FC drop

Mustard level FC for 50CYA is 30
Click to expand...

Yeah, the mustard algae reoccurring is my major concern since it's happened a couple times now unexpectedly.

Just to be clear, you are saying that now that my SLAM is complete and my FC is currently 21, I need to now raise the FC level even higher to 30 (my CYA is still 50) for 24 hours???

No one has ever suggested this but I really would like to not see the mustard algae again.

Where do you find the "mustard levels" you speak of? Are you essentially saying that doing the SLAM at my recommended FC / CYA level isn't enough to kill the mustard completely? If so, that would certainly explain why it keeps occurring.
 
Thx. I just came across that pool school mustard algae page too.

Should I reduce the SLAM from the start or just jump into the Mustard shock.

I happy that at least I may now know why I haven't been successful in getting rid of the mustard algae - I wasn't doing the MA level shock after the SLAM.
 

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