Help...Mustard Algae, Fe stain, or ???? What I have tried so far with no results

May 14, 2016
8
Abilene, TX
#1
Hello everyone,

I had gone out of town for about 10 days and came back to a pool with yellow all around the perimeter and on steps for the most part. Some areas are heavier than others. It will not brush off at all, even after a very tough scrub. Embarrassing as it is, I took a sample in to a local pool supply store to get a recommendation. Below are the stats they gave me.

pH: 7.8
FC = 0 (I was gone for 10 days and only use bleach..so, I figured this much)
Saturation index = high (what is this???)
TA = 112
TC = 0
Total Hardness = 550
CYA = 35
TDS = 1700
Optimizer Plus = 9 (again, what is this??)

They recommended to shock the pool with 4 pounds, scale inhibitor (2 quarts) and to keep 4 tabs of Cl in the pool at all times. Later, I finally was able to get ahold of my pool builder for a second opinion and he said it was yellow algae without a doubt and that it can be hard to scrub off. So, I decided to go his route and used yellow out per package instructions and then shocked with 3 pounds that last Thursday. At this time, nothing has happened. I tried the Vitamin C tablet on one of the areas and the area did not go away or lighten either.

Per my test kit, TF 100, the results today (Saturday) are as follows:
FC = 4
CC = 2
TC = 6
CH = 850
TA = 240
CYA = 40
pH = 8.2 (maybe a little lower)

Should I try the scale inhibitor or just go back to an extreme shock of the pool. I should also mention that we have our house on the market and really want this to clear up ASAP as it doesn't give a good impression.

Oh, the pool characteristics.
In ground, gunite pool
DE filter
~ 19,000 gallons
Daily use of my polaris and roughly weekly brushing.

Suggestions?

Thanks in advance.
 
May 14, 2016
8
Abilene, TX
#3
I wonder if that isn't iron staining since the pH is so high.

Try rubbing a Vitamin C tablet on the yellow. If it lifts off right away, it's metal stains.

I tried rubbing a 500mg Vitamin C tab on it and it didn't appear to help at all. Did I purchase the correct product? I just bought the OTC vitamin C at the pharmacy. I agree though, I really thought it was a metal stain.
 
May 14, 2016
8
Abilene, TX
#7
Drop the pH and maybe leave the pill sitting on the stain for a minute or so.
Ok. So I got the pH down to 7.5 today with muriatic acid. The TA is still 240 though. I also purchased a wire brush to give that a try and I felt like I made some headway after lots of brushing, but pictures say otherwise. I have also tried another vitamin C tablet. I let it sit in one spot for 5 minutes with no reaction and then I scrubbed the area with the remainder of the tablet. Again, no reaction.

Overall, I feel the yellow may have been reduced since Thursday 'some', but that could be my imagination.

IMG_5814.jpg
IMG_5818.jpg

Here are a few pics from tonight to give an idea of what I am seeing. Please note that these pics are at night with using either the pool light or The flash from my phone.

Should I do another shock,triple shock, this time with 6 pounds or add about 1 gallon of muriatic acid to drop the pH to 7, and hopefully the alkalinity too. At that point I could try the ascorbic acid test again.

Also, I still have that scale inhibitor I originally bought, I was planning on taking it back, it should I just give it a try. I am afraid of just throwing everything in the pool as it could be counterproductive and really throw the chemistry out of whack.
 

JamesW

TFP Expert
Mar 2, 2011
12,837
#8
Your numbers indicate high risk for scale. I think that that is part of the problem. I would suggest getting the TA down as quickly as reasonably possible.

Try to keep the ph down to 7.2 and scrub as much as possible with a plastic bristle brush.
 
May 14, 2016
8
Abilene, TX
#9
Your numbers indicate high risk for scale. I think that that is part of the problem. I would suggest getting the TA down as quickly as reasonably possible.

Try to keep the ph down to 7.2 and scrub as much as possible with a plastic bristle brush.

Ok. I have added a few gallons muriatic acid in64 oz increments and now have the pH around 7.2 with a TA of 140. With the rate it has been going, I am going to add another 64oz and should have a TA around 120 in the AM with my pH being stable at 7.2 as I am running my bubblers constantly to help introduce air to increase my pH.

It appears to both my wife and myself that the yellow areas are getting better. Unfortunately, I have to go out of town tomorrow and dont feel comfortable starting the ascorbic acid treatment and not being able to see it through. If the stains are getting better, and my wife said she will continue to brush daily (at least the problem areas) as best she can, will it be okay to leave it like this for a week if I have the pH in check now and my chlorine levels up? I am going to keep running my pump, but not using the bubblers and just the returns as well as giving my CL levels a little boost with bleach and keeping some tabs in while I am gone. Will these stains become more difficult to remove over time and do I really need to get them taken care of ASAP?

Also, I was initially sold on some Bioguard Stain Inhibitor by the local pool supply. I was planning on returning it, but should I go ahead and use it?

Thanks to everyone for helping.
 

JamesW

TFP Expert
Mar 2, 2011
12,837
#10
I don't think that it's algae or iron. I think that it's probably mostly scale with various integrated contaminants.

I would suggest maintaining the chlorine at normal levels, the ph at 7.2 and brushing.

A stain and scale sequestrant should help.

If you can include some pictures of the progress, that might help.
 
May 14, 2016
8
Abilene, TX
#11
I don't think that it's algae or iron. I think that it's probably mostly scale with various integrated contaminants.

I would suggest maintaining the chlorine at normal levels, the ph at 7.2 and brushing.

A stain and scale sequestrant should help.

If you can include some pictures of the progress, that might help.

Update: I am out of town still and will be back tomorrow for pictures, it my wife says the yellow has not gotten any better since I have been gone. Before I left, I did had tr stain and scale sequestrant and she has been brushing the problem areas daily. She took another sample in to have it tested and they said the chemistry "looks good." She has the paperwork and I will compare it to my results tomorrow, but don't have the actual numbers with me. She explained to them what is going on and they ran another test that found high phosphate levels in the water. They didn't think this would cause the yellow, but could prevent it from getting better. Is this accurate? All in all, they sold her some phosphate binder, but said it could be returned if I didn't need it. Thoughts?

I will be back home tomorrow and will be able to get some new pics to post up as well as the latest chemistry.

Thanks to everyone for the help.
 
May 14, 2016
8
Abilene, TX
#12
Update. I reviewed the test results from the local company and they had shown:

TC 1.5,CYA 40, pH 7.8, TA 92

I went with their tests and added 3 gallons of bleach and up to 1 gallon muriatic acid throughout the day. We had a big thurmderstorm come though last night and I was. It able to assess the changes. The pool had taken on an extra 2.5 inches approximately. I rechecked the labs and they are as follows with the Taylor test kit.

FC 4, CC 0.5, TC 4.5, pH 7.2, TA 80, I kind of am questioning the accuracy of my current test kit. Not so much the accuracy but the integrity of my testing solutions really.

Here are a few pics of the pool tonight (sorry, I should have waited until after netting out the debris on top)
IMG_5907.jpg
IMG_5876.jpg

I am am going to pick up some more vitamin c tabs tonight to recheck for iron just in case, but I really do t think that is what it is. Also, my wife and I believe that using the yellowout and then shocking gave the most improvement, albeit, very minimal.

What should i do next?