SLAMing/Mustard Algae Question?

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cajuntwin

cajuntwin

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Aug 22, 2016
11
Kaplan, Louisiana
Hi all, I just left "the dark side" of going to the pool store to get straight answers after finding TFP.

Here is my issue, I believe my pool has Mustard Algae. I attached a couple of pics so that you can see where I am right now.
The algae began to appear quite a while back only as a yellow cloud when I would brush.
I used something the store sold me to get rid of it and that seemed to work, but over the last several months I have begun to see the green/brown color on my steps and walls of the pool.

After searching online I found TFP and began SLAMing my pool on Monday (8/22) and raised my FC levels to 21 (I used the iphone poolschool app and it showed to shock at FC 21 for a CYA of 70)
Here were my test numbers on Sunday before I started SLAMing:

PH-7.5
FC-7
TA-110
CH-270
CYA-70
TEMP-94

I check my FC levels twice a day (morning & night) and shocked to keep around 25.
I have not finished SLAMing because my FC levels have dropped overnight between 2-3 each night.
First question is should I be shocking at 10.5, 27.5 or 40.5 during SLAMing?
Second, when is it recommended to shock at the maximum mustard algae level of 40.5?
Lastly, I am running my pump 24/7 but have turned off my SWG, is that the correct procedure?

Thanks in advance for any help!


IMG_1097.jpgIMG_1099.JPG
 
Welcome to TFP! Good to have you here :)

First up, use PoolMath on this website. A variety of problems have been reported from the phone app. Shock level for CYA at 70 ppm is an FC evel of 28 ppm.

The likelihood of having mustard algae is relatively low, but the fix is just a 24-hour method, so may as well do it anyway, or read up on identifying mustard algae. The method is linked below, but essentially you just complete your SLAM per all three criteria, and then use the mustard algae shock level for 24 hours.

Pool School - Mustard Algae

TFP recommends turning off the SWG, and yep, keep the pump running 24/7
 
Thanks needsajet for all the good info.

Not sure what this is if not mustard algae? I raised my shock level to 41 last night (Friday) and will hold until Sunday morning and see if this works. Today (Saturday) the stain does look a little lighter, but still noticeable.

I read on a thread in TFP to put a chlorine tablet on the stain to see if it reacts and it did. As you can see on the step picture between the top 2 diamonds there is a clear spot, that is where I put the chlorine tablet and it removed the stain. So, I concluded this is organic, just not reacting to my constant brushing like I would have hoped it would.

Thanks again for the help!
 
Not sure which?

I am guessing Mustard Algae because I had a cloud in the water when brushing a couple of weeks before the discoloration on my steps and pool walls. If I knew about TFP at that time I would have done a SALM right away, but added something I bought from the pool store and it cleared the cloud and nothing was on my steps or walls. Now I have only discoloration on my walls and steps and nothing clouds when brushing and water is clear with no green tint.

I had water tested an no metals present.
 
So you have stains. Need to identify if it is organic or metal staining.

Hold a tri-chlor puck directly on the stain for a bout 3-5 minutes. If it removes or significantly lightens the stain, then the stain is organic.

If that puck does nothing, crush up some cheap vitamin C tablets in a sock and hold that sock down on the stain. If the stain is metal, it will lighten or eliminate the stain in that small spot.

Let us know.
 
I put a tri-chlor puck on the steps last Monday (you can see the lighter area between the brown tiles on the first step in the picture) and it lightened significantly that is why I believe it to be organic.
Currently on 36 hours of Mustard Algae shock level of 41 since Friday night and not much change in color of stain, brushing daily (sometimes twice a day).
Should I just hold this shock level and continue to brush until stain clears?
Whew... going through a lot of chlorine, thanks again for all your help!
 
First thing either way is to get the SLAM done, so we can stay on that track for now.

It's possible you have a bit of iron staining, and that can be dealt with after the SLAM is completed.
 

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Passed the SLAM last night lost only 1 on FC and 0 CC and water is clear, stain still there...
It seems I have iron staining as needsajet mentioned above.
How do I remove an iron stain?

Thanks for everyone's help, I would have thrown in the towel without your guidance!
 
Hi cajuntwin - wishing you good luck on your adventure! One question I had (and I reread your messages a couple of times) is what are you using for shock? I didn't see any mention of liquid chlorine and just double checking that you are in fact using that and not powdered shock (trichlor) to keep your FC at SLAM level. If I did in fact miss it, my apologies!

Don't want your CYA to get too high (even though you're good at 70 with a SWG).
 
Cajuntwin, if you confirmed iron staining, please also let me know the following

1. Are you on well water?
2. If not, do you know the ppm of municipal water in your area?
3. Have you historically or ever used metal sequestrant?

If you're not on well and have low levels of iron that have simply accumulated and stained in the course of SWG operation, and haven't previously used it, you might want to try a startup dose of Jacks Metal Magic Purple formulated especially for SWG. Salt itself adds trace amounts of iron. Here's a link to the recommended swg sequestrant: Amazon.com : Jack Garden

There's a chance it will remove the stains without having to do the Ascorbic Acid treatment, the latter of which is a bit of a pita in that after the treatment some folks end up struggling with either algae from being at low FC too long (leftover AA in the water fights chlorine) or with restaining from raising the FC too quickly and letting ph rise too much.

Also see if keeping your ph lower, eg 7.2ish, helps lighten stains.

If you're on well water, there are other prefiltering tips that can help reduce load.

Its also worth checking to see that there's nothing corroding, eg ladder nuts, etc. some people will plumb an inline sacrificial zinc anode like this one to reduce galvanic corrosion with heaters, etc., but reviews are mixed on the need : Amazon.com : Pool Tool 104C Zinc Anodes for Chlorine-Generator Salt Water Pool : Patio, Lawn Garden

If you do decide instead to do the AA treatment, which most reliably lifts iron stains, you'll need sequestrant anyway for the process so the Jack's will be required either way. The only reason I suggested trying it alone is because I've seen it immediately lighten remve iron stains on steps at start up.
 
I ran OCLT last night and passed again, no loss in FC at all, CC still zero and water is clear.

swampwoman, I am on municipal water and did have the water tested at Leslie's Pool Store and it showed copper-0 and iron-0 but based upon other test not sure I trust their findings. I don't know the ppm of our municipal water.

Not sure about the metal sequestrant (because I normally put whatever pool store recommended), but I really haven't had many problems with my pool over the years and had a complete renovation done 5 years ago. I do have trouble keeping my ph low because of a small sitting area attached to the pool with jets and a waterfall causing aeration.

Nothing corroding in my pool to cause iron, no metal ladder, metal steps nor a heater. But after reading a few post on this forum about fertilizer, I think it may be from the landscaping company I hired to maintain my yard. I watched them scatter fertilization pretty liberally and some may have gotten into the pool.

I will try Jack's Magic Purple and see if I can clear without doing the Ascorbic Acid treatment and try to keep my ph closer to 7.2.

Again, thanks for all your help!!
 

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