Help Please! Stains on Gunite Pool (with pics)

[illtiger1]

First post of the year and I would like to say that the great advice I received from here last year for our pool closing proved to do the trick so a big, much deserved "thank you" to everyone here. Now to the current problem. I have a gunite inground pool with about 17,000 gallons of water. We opened it fine and just had the water tested and everything is satisfactory. The only rare problem this year is that we are receiving a ton of rain this summer in CT. We also have a leafy tree whose branches stretch out over our pool. We have been getting brown stains on the bottom of our pool in the shallow end and on the sides. I have tried using vitamin C to remove the stains, black algae remover, algae remover, and granulated shock with no success. Here are three pics:

Thank you for taking the time to look.

 

[lovingHDTV]

These look exactly like the organic stains I get when leaves/twigs from the trees fall into the pool. By keeping the proper FC level they will go away.

If you want them to go away quicker you can spot treat with chlorine, I've used granulated chlorine for this, but anymore I just wait them out.

If you want to use granulated chlorine I use a piece of PVC pipe to deliver the chlorine directly onto the spot. I do this by putting the piece of pipe into the water directly over the spot, then put the granulated chlorine into the pipe. It acts as a conduit and puts the chlorine exactly in place.

You don't mention what type of pool you have but you should not do this on a vinyl pool. YMMV

dave

 

[frustratedpoolmom]

I have tried using vitamin C to remove the stains, black algae remover, algae remover, and granulated shock with no success.

Please describe what you did when you used these products.

Have you set a trichlor puck on the spot to see if it fades?

What type of surface is the pool?

 

[Butterfly]

That looks like organic stains to me, too. In fact, if I had to guess, I'd say oak tree.

What I do for mine is always remove the twigs as soon as possible and increase my FC level just a little. They fade fast.

 

[illtiger1]

It is a gunite inground pool with a Hayward DE filter. I have tried using vitamin C in a sock to remove/scrub the staining because I thought it may have been metallic staining. I have also used 6 lbs of granulated shock in the pool and algae removers. I used these products as directed on the bottles/packages and ran the filter. I also have jumbo tabs in a floater as well. I just can't seem to get rid of the stains. Last year, they eventually came up, but this year they have not. Thanks.

 

[illtiger1]

What is the easiest way to increase my FC level if it will help to remove the staining? I'm a newer pool owner and inherited it when I bought my house last year. My other friends and family deal mostly with above grounds so I have little reference. Thanks.

 

[reebok]

I recommend you read all the pool chemistry articles, but this one specifically will answer this question.
pool-school/types_chlorine_pool
the other articles will answer the questions you didn't know you had.

 

[frustratedpoolmom]

Bleach or liquid chlorine. Learn how to use the Pool Calculator - there is an article in Pool School that tells you how. It can help you determine how much of each chem to add, to reach the desired levels. It's much more accurate than dosing instructions on chem packages.

Try taking a chlorine tablet, and setting it on the stain...see if the stain fades under the puck.

 

[illtiger1]

Yes, the stains fade underneath pucks. Now I will dose the pool with liquid chlorine. Thank you.

 

[mitchtg]

I have just found your entry illtiger1. We have exaclty the same problem, the stains look identical and seem to be cause by soemthing dropping from overhanging trees. No sure what. Clorrine tablets remove the stains but they keep coming back. Funny thing is, they did not appear the first 3 yeras we owned the house, but last year and this year they are there a lot. Did you find a long term sustaibale cure. Could it be a metal build up over time, activated by an organic dropping from the trees?

 

[rodaniel]

For what it's worth, I'm a relatively-new pool owner (came with our new house back in Feburary) and had been battling this same problem. Given that the stains look like rust, I understand why the inclination is to think the cause is something metallic. But the real culprit is tannins in the leaves, seed hulls, flowers, nuts and other debris that falls from trees. Oak trees have an especially high content of acidic tannins and acorns or seeds that fall into your pool can begin to stain within a matter of a couple hours.

The good news is that chlorine will fade those stains right away.

The better news is that a chainsaw is cheaper than chemicals, in the long run.