Just getting started - brown markings on tile

[Jen_TX]

Hi everyone! I joined you a couple weeks ago and haven't posted yet. I'm completely overwhelmed trying to learn all there is to learn about my pool. We noticed today on the tile grout that there is something brownish (see photo).



We have always had some buildup that I am working on removing a little at a time, but we haven't noticed this brown until today. My husband thinks it's a chemical issue or dirty water. I think it might be from our Crepe Myrtle trees. You see, whoever built this 14 years ago put 5 Crepe Myrtle trees surrounding my pool. Can you say pain in the butt? We are CONSTANTLY cleaning the blossoms out of the pool and baskets. Needless to say, they won't be there a whole lot longer, but their shade sure is nice.
Anyway, we had a rainstorm yesterday and the entire deep half of the pool was covered in Crepe Myrtle blossoms that I skimmed out. I did get the Taylor test kit and did my first test on my own yesterday. Here were my numbers:

Free Chlorine: 2.2
Combined Chlorine: 0.4
Alkalinity: 140
pH: 7.9
Calcium Hardness: 600
CYA: approximately 100 - 120 (different numbers from different testers)

I had been bringing water samples to the local pool store to have them test before trying on my own, so if you are interested to see if any numbers are going up/down/whatever, I can provide earlier numbers. I shocked the pool last night as we are having company over this evening to swim, and, after that storm I wanted to shock it.

My question is - does anyone have any idea what these brown markings on the tile could be? THANK YOU in advance for any help!

 

[duraleigh]

I can answer your question indirectly. with a CYA of 100+, you have nowhere near enough chlorine in your pool to prevent staining or algae either one.

While you are reading "The ABC's of Pool Water Chemistry" up in Pool School, I would suggest you elevate the chlorine on your pool to up around 10 ppm and then see if that makes any difference.

Secondly, your CYA is so high it almost makes your pool unmanageable. You should drain your pool by about 1/2 to get your CYA to a manageable 50-60 ppm.

Big steps, I know, but you have a troubling situation that needs correcting and then you can address your stains.

 

[Casey]

I am in total agreement with duraleigh. You have got to get that CYA down.

Although you just joined and there is a lot of info to be learned and used to get you to a trouble free pool, do not overwhelm yourself. All you have is time and you'll get a handle on it. Your biggest issue right now is that outrageous CYA level and your very low, non existent FC level.

 

[Jen_TX]

Thanks for the replies.

A couple follow-up questions:

1) I think I've accepted that I'm going to have to replace the water. I have a plaster pool. I can't drain below the coping tiles, is that correct? (See what a newbie I am??)
2) Once we get the Chlorine/CYA under control, will I be able to remove the staining? I read another thread where someone mentioned scrubbing it with 100% bleach.
3) I can use regular Clorox bleach, correct? That pool chlorine is pricey. Phew!
4) While I am raising the chlorine that high, is it safe to use?

THANK YOU for your help.

 

[Jen_TX]

duraleigh, another question: you mention raising the chlorine to 10 ppm. is that to shock it, or to remove the staining?

thanks again!

 

[Abigail K]

Replies in red.

Thanks for the replies.

A couple follow-up questions:

1) I think I've accepted that I'm going to have to replace the water. I have a plaster pool. I can't drain below the coping tiles, is that correct? (See what a newbie I am??)

In general, it is safe to drain below the coping tiles, provided the temperature isn't too high and you don't have high ground water. Other members will be able to give you more specific recommendations.

2) Once we get the Chlorine/CYA under control, will I be able to remove the staining? I read another thread where someone mentioned scrubbing it with 100% bleach.

It will be a lot easier to remove the staining once the CYA is under control. We will advise you on how to identify the stain and how to remove it.

3) I can use regular Clorox bleach, correct? That pool chlorine is pricey. Phew!

Yes, regular Clorox bleach is ok. Pool chlorine is more concentrated and may work out to be more cost-efficient. See this thread and/or Chlorine price per ounce calculator.

4) While I am raising the chlorine that high, is it safe to use?

We say it is safe to swim up to SLAM levels, provided you can see the bottom (for safety reasons). Wear an old suit and shower after using the pool.

THANK YOU for your help.

duraleigh, another question: you mention raising the chlorine to 10 ppm. is that to shock it, or to remove the staining?
The 10ppm recommendation is based upon your current CYA levels to achieve proper disinfection. It may help to remove the staining if the stain is organic.

thanks again!

See also Chlorine/CYA chart.
Post back if there's something you don't understand.