Yellowish Stains on DiamondBrite Plaster

[mccurdyp]

I have recently developed some stains on the surface of my pool finish. There are quite a few and brushing rigorously doesn't get rid of them.
I'm worried that a product I added last week called 'Sparkel Conquest' may be the culprit as it's mainly along the edge where I had poured in the product




Has anyone had experience with this?
I'm thinking I'll need to drain the pool and give it a good acid wash. BTW, the chemistry is good and I'm sure it's not a result of metals in our water here

 

[Bperry]

I have recently developed some stains on the surface of my pool finish. There are quite a few and brushing rigorously doesn't get rid of them.
I'm worried that a product I added last week called 'Sparkel Conquest' may be the culprit as it's mainly along the edge where I had poured in the product


View attachment 565812View attachment 565813

Has anyone had experience with this?
I'm thinking I'll need to drain the pool and give it a good acid wash. BTW, the chemistry is good and I'm sure it's not a result of metals in our water here

Hard to know without seeing the actual chemistry reaults. Theres another report of that product causing cloudy water and that its a sequestrant. Is there a reason you added it?

 

[JamesW]

I'm thinking I'll need to drain the pool and give it a good acid wash.

I would not acid wash.

Try vitamin C on a spot.

 

[JamesW]

 

[mccurdyp]

Hard to know without seeing the actual chemistry reaults. Theres another report of that product causing cloudy water and that its a sequestrant. Is there a reason you added it?

To remove some stains

 

[mccurdyp]

I would not acid wash.

Try vitamin C on a spot.

So grind down some vit c and apply it while stain is wet? I'd need to empty the pool of course. Why not use an acid wash?

 

[JamesW]

Just drop a vitamin C tablet on a spot without draining any water.

Muriatic/hydrochloric Acid destroys the plaster.

 

[jesse-99]

You don't need to drain water to try a vitamin-c test. Get some vitamin-c tablets and hold them against the stain (with your foot or hand if need be) for 30-60 seconds and see if they lessen or disappear. If they do, it's iron staining (though iron staining is typically more red/brown'ish than yellow). It's a very quick/EASY first step for testing without much effort or cost.

How long have the stains been there?

 

[jesse-99]

Also, if the stains are organic in nature, a chlorine tab against the stain should remove it (for example, stains left by leaves and other organic materials). That, and the vitamin-c test, are super easy and cheap and help you determine what the staining is/isn't, before taking more drastic steps like draining a pool.

 

[Bperry]

To remove some stains

So the stain remover created more stains? Are the colors the same as before and after?

 

[mccurdyp]

You don't need to drain water to try a vitamin-c test. Get some vitamin-c tablets and hold them against the stain (with your foot or hand if need be) for 30-60 seconds and see if they lessen or disappear. If they do, it's iron staining (though iron staining is typically more red/brown'ish than yellow). It's a very quick/EASY first step for testing without much effort or cost.

How long have the stains been there?

Thank you! - I'll test it out today. I did see you can buy ascorbic acid for Pools on Amazon, so if it works I guess I could get some - or just buy a bunch of tablets and hold them against the stains

 

[mccurdyp]

Also, if the stains are organic in nature, a chlorine tab against the stain should remove it (for example, stains left by leaves and other organic materials). That, and the vitamin-c test, are super easy and cheap and help you determine what the staining is/isn't, before taking more drastic steps like draining a pool.

Thanks for the tip! Along with Vit C test, I'll try that out

 

[mccurdyp]

Problem Solved!! I think I must have had Algae Bloom. I tried the trick with my chlorine pucks and it cleared out a stained spot, so I added a bunch more (5 in total in my 7500 gal pool - too much?). And it's starting to remove all the stains as I move them around and do a bit of scrubbing.
It's been very warm and sunny here for last few weeks (pool temp around 90) so I assume that helped along the algae.
I have a SWG and I thought per the control unit that the salt level was ok (see following). I did a complete reading and have the following:
Free Cl .4 ppm
Combined Cl .4 ppm
these should go up over the day as chlorine tablets dissolve. Will check again tomorrow
Salt 2200 ppm - way too low
since I'm leaving soon and will be using chlorine tabs, I probably won't add any until I return
pH 7.4 - OK
Alkalinity 60 ppm - OK
CH 120 ppm - I added calcium

I am leaving Honduras for the summer soon and will be covering the pool, turning off the SWG, reducing pump run time to 2 hours, and having my gardener add a Chlorine puck weekly (which has worked well in the past).

So, thank you all for the suggestions to try putting ascorbic acid or chlorine on the stain to see what happens. I know now I probably won't have to drain the pool after all. And although I didn't do it, when I return and see any yellowish green spots I'll try the Vit C trick too