Fiberglass Staining?

[Bluthgg]

Hi all,

Been living a relatively trouble free pool life until yesterday! I do not close my pool for the winter so everything is still running - I typically check pH/FC daily and the other tests in the TF test kit monthly. I recently noticed some discoloration on the steps/edges of my fiberglass pool. It's hard to see until up close. Attached is a picture.

I have a Nautilus CC plus that I use weekly to keep things clean, but other than that usually isn't too bad to keep up with everything.

My readings from yesterday:

FC: 2.5
CC: 1
PH: 7.5
TA: ~50
CCH: 175

I added some baking soda yesterday, per the poolmath app to raise the TA. I'll be rechecking later today as well as taking a sample to a pool store to double check. I do have a salt cell but it's been off for at least ~6 weeks due to the water temp.

Any ideas? I thought maybe it's calcium but my calcium levels aren't high and PH is typically in the 7.5 -8 range throughout the season. I thought it had to be typically pretty high to get that kind of staining.

 

[YippeeSkippy]

Do you use any other chemicals in your pool? Any copper containing algaecides? Could any lawn fertilizer type product have scattered on to your stairs?

You don't list your CYA...what is it?

Why do you take water samples to others to test when you have the primo test kit on the market?

Maddie

 

[Bluthgg]

It is possible some lawn fertilizer got on the stairs/in the pool. I have a company that comes out and treats the lawn during certain months. They are pretty careful but it’s been windy. I can sort of see it on the other steps in the deep end and the walls but it’s really hard to see in certain light.

CYA is ~30. That is one of the hardest tests for me to measure so far. I know it’s low for salt but during the summer/swim months it’s typically around 70. Since it’s too cold for the salt generator I’ve just been using liquid chlorine.

As for taking the water to test at another place it’s mainly to make sure I’m not missing something with the tests. It looks like calcium but I thought that would only occur if ph was high and CH was also high?

 

[Bluthgg]

Couple more photos. @YippeeSkippy no other chemicals used other than liquid bleach, salt, borax, baking soda and muriatic acid.

 

[Bluthgg]

Well the test results from the store were pretty much right on the money. I added baking soda and calcium to get my TA and CH levels up and retesting myself showed a TA of 80 and a CH of 225.

The guy suggested using some citric acid on the steps/area and the brushing about 10 seconds later and seeing if it improves.