Remove stains from plaster pool

[TurboMatt]

After several weeks, my pool water is finally looking good! All of the water chemical levels are excellent, per my test results and the local pool supply. Anyway, I'm now left with stains all over the plaster floor and part of the walls. What are my best options to help alleviate some of the staining without draining the pool? I would like to put off draining the pool until fall, if possible.

This is what I started with.



This is how things look as of this morning.

 

[ajw22]

Determine if stains are organic or from metals. Read Stains in Your Pool - Trouble Free Pool

 

[TurboMatt]

Thanks for the link. I recently purchased the house and can only assume they are organic. I removed 4-5 wheel barrow full of leaves, sticks, etc from the pool when I initially opened it. So that had been sitting at the bottom of the pool for several years.

 

[ajw22]

An elevated level of CL will get rid of organic stains slowly over time.

 

[TurboMatt]

How high is 'elevated'?

I've also read about lowering PH levels for a week or so will help to "acid wash". The water would obviously be un-swimmable but is that a suitable option?

No Drain Pool Acid Wash

How to do a no drain acid wash on an inground plaster pool finish, to remove stains and scale and brighten the pool.

blog.intheswim.com

 

[Mr Bruce]

Somewhere between the top of your target FC and SLAM FC.

I would not recommend holding the pH artificially low for a week. Just raise the FC and they will go away. Pool Owner Patience!

If there are particularly "bad" spots you can put a puck on them for 15-30 minutes and it will go faster.

 

[ajw22]

To remove organic stains raise the FC up between 60% and 100% of shock level for your CYA, Chlorine / CYA Chart, and brush often, daily if you can.

Be patient. It can take a season.

 

[TurboMatt]

I am completely fine with it taking time. My concern is basically the best way to alleviate them. So if shock is around 10-12 ppm, should I plan to keep the CL around 6-8 ppm?

 

[ajw22]

I am completely fine with it taking time. My concern is basically the best way to alleviate them. So if shock is around 10-12 ppm, should I plan to keep the CL around 6-8 ppm?

I would go 6-9 ppm. You want to keep FC below 10 ppm as pH test becomes unreliable after 10 ppm.

 

[markayash]

Before you do that try rubbing one with a puck and see if it goes away..Sounds like it is but easy quick way to verify before you attack it.

 

[TurboMatt]

Ok, sounds good. I'll try the puck idea sometime in the next few days.

 

[markayash]

Ok, sounds good. I'll try the puck idea sometime in the next few days.

If that doesn't work try cheap plain vitamin C.

 

[TurboMatt]

Is there a procedure for the vitamin C treatment?

 

[markayash]

Is there a procedure for the vitamin C treatment?

Just put one in your hand and rub it on the stain. You will know if it works in a few seconds. Tablet didn't do much but I rubbed one on a streak and was magic

 

[TurboMatt]

Sounds too easy! I'll give that a shot tonight.

 

[Mr Bruce]

Vitamin C tablets are for metal stains, puck/elevated FC are for organic stains. Seeing that TurboMatt posted that there was leaf debris on the bottom of the pool and looking at the video, it's very very likely organic staining. Vit-C won't hurt anything to try, but I'll bet it's not going to do anything.

 

[TurboMatt]

You may very well be correct. I'll try the Vitamin C tablet in one area and the puck in another area. I'll report back with the results.

 

[TurboMatt]

Looks like they stains are absolutely organic. I took a large puck and scrapped a section. It seemed to help. So, I let it sit on the floor for a bit and kept checking on it. After around 45 mins, there was a completely clean circle under it.

Now, what is the best way to scrap around the floor and wall?

This is all that I have found - Pentair 542068 Algee-Gon Chlorine Tablet Holder

 

[jimim]

If that worked I would do as others r saying and sit back and relax. If u leave the puck on too long u can hurt the plaster also. I would just raise the fc level. At least that way u are also keeping the pool water clean also.

 

[TurboMatt]

Sounds like a plan. I'll do as you guys advise and raise the FC level up a bit and see how things progress. I guess it's just time to enjoy the water!