Brown stains appearred after new Diamond Brite application

[ackrill]

Hi, I am new to this forum. Or any Forum for that matter. But I am upset enough to try anything. I bought this house in 2003. It came with the pool built in 1992. The Diamond Brite finish was attractive but as the years went by it started getting chips and divots. I had it resurfaced 9/21/15.
It looked great at first but after a few months I started seeing large blob shaped brownish stains mostly on the bottom. The contractor came back and looked at it and said it was from my algaecide. I think he is blowing smoke. He has offered to acid wash it if I drain it.
So I had the Diamond Brite (SGM) rep come out and look at it. He said it was MOTTLING and gave me 2 quarts of a powder (their version of JACK'S MAGIC THE MAGENTA STUFF). He gave me a printout of the procedure. It involved 1 gal of muriatic acid/2 thousand gallons of water. I ran the pump 24/7 and brushed the pool 2/day for 4 days. IT WORKED!

But after a few months the stains came back. I maintain my own chemicals and every time I get the water sampled it is very close to perfect. I use PinchaPenny.
View attachment 54435View attachment 54436View attachment 54437
I am afraid to have the acid wash because it might roughen the surface and promote algae. Who's to say the stains won't come back.
Is there a cure? Thanks

 

[YippeeSkippy]

Welcome to TFP, Ackrill

If I had to guess, I would guess those may be metal stains. Either from your fill water or from products you've added to the pool. Many inexpensive algaecides contain copper, for example.

We don't trust pool store testing as a rule (too sloppy, too inaccurate, too many folks looking to sell you a "cure"). We encourage folks to have their own reliable test kit (to include the all important FAS-DPD test) because no one is going to care about your water as much as you do. That said... we do suggest folks ask the pool store to test for metals.

One simple test to help diagnose this is to get a sock full of cheap, crushable Vitamin C tablets and crush them up a bit in the sock. Then hold/rub this against a stained area and see if the stain lifts?

Next- Go to another area of stain and hold a chlorine puck against the stain for a few minutes and see if that changes it?

If the Vit C changes it, it suggests metals. If the puck lightens it, it suggests organics.

How are you sanitizing your pool? Do you ever do your own testing??

Quick Reads --> ABCs of Pool Water Chemistry and Pool School - Metals in the Water and Metal Stains

 

[JamesW]

Might be from copper algaecide. Are the stains definitely brown or could they be gray?

 

[ackrill]

The stains appear brownish. My algaecide is ALL IN ONE by SUNCOAST CHEMICALS. There is no mention of copper in the ingredients, just POLYETHYLENE DICHLORIDE. I add it every week as per instructions. I also test for chlorine and PH weekly. I took a water sample for testing on Friday and it came back OK. Please keep in mind that in 12 years I have never had this problem. It started a month or 2 after the new Diamond Brite was installed. I am not doing anything differently. The stains are smooth to the touch. When they went away after the acid treatment they came back in the same places plus some new ones.
OK, I have conducted the test with vitamin C and chlorine tablet. I left it overnight. You can see in the picture that the chlorine tablet cleared up the stain and the vitamin C made it worse. I also dropped a tablet on the bottom by the drain. You can see where it also cleared up the stain. I hope this gives some insight.

 

[YippeeSkippy]

I think we need more exact pool test results than "OK". I would hope you would get one of the two kits we endorse as they are accurate, easy to use and we will be speaking the same test language. The Taylor's K-2006C or the TF-100, both avail from TFTestkits.net ; or PoolSupplyWorld.com . We need to know the following results:

FC
CC
pH
TA
CH
CYA

Something is definitely wonky with your chemistry, but I'm just not sure what yet? Did you ask the pool store to run metals test?

Yip

 

[JamesW]

I'm still thinking copper. Don't know what else would do this.

 

[jblizzle]

Doesn't the fact that the Vitamin C made the stain worse indicate it is likely copper? {I can not recall and would have to go search for that information.}

FYI, do NOT just leave those trichlor tablets sitting on the plaster as that is sure to cause damage.

I agree with the others that you should get a recommended test kit, stop trusting the pool store testing, and stop adding unnecessary chemicals in your pool. Just because you have done the same thing for years, does not mean what you are doing is "right" or the best method.

- - - Updated - - -

Here is the first result I found from a search:
Vitamin C left two very very dark spots that don't brush off

Definitely points to copper stains ... likely due to the algaecide you have been using.

EDIT: Although if you are using what you say, than that should be poly 60 and not have copper in it.

 

[YippeeSkippy]

Any chance you used some Suncoast Silver Algaecide by mistake instead of the Suncoast All in One Algaecide?

 

[ackrill]

I will have to get more thorough testing. But I have never used anything with copper in it. Just the Suncoast All In One.
OK , assuming I have copper stains, is there a treatment for it?
Also what do you think of the SGM rep who said it was MOTTLING from the new Diamond Brite?
And the pool store rep who says it is hydration from the new Diamond Brite?
Thanks for your help.

 

[ackrill]

I just remembered something. On the bottom of my brush pole I installed a 12" long copper tube over the thin aluminum pole to protect the pole where it scrapes on the bullnose tiles.
But once again it is something I have done for 12 years with no stains.

 

[YippeeSkippy]

I just remembered something. On the bottom of my brush pole I installed a 12" long copper tube over the thin aluminum pole to protect the pole where it scrapes on the bullnose tiles.
But once again it is something I have done for 12 years with no stains.

Do you have periods that your water pH is particularly low and you left the brush and pole in the pool?

 

[ackrill]

no, never.

 

[jbeall]

Curious... who did your Diamond Brite? We live in Margate also. Had ours done through National Pool Supply. They have been our pool service since we bought our house back in the early 1990's