Elevated FC level to remove stains in plaster?

[JT2006]

I am 5 months into ownership of my first pool. As I said in a previous thread the house/pool we purchased was a foreclosure so the pool had been negelected and plaster is stained. The plaster is still in good shape so I would like to get rid of the stains and forego a re-plaster for at least a year or two.

My first choice was to drain and acid wash but in my earlier thread it was suggested that I maintain higher FC levels and brush to try to lighten the stains first. Now I'm wondering since no one is using the pool if I can bring the FC up to shock levels to see if it will lighten them? would this be productive at all or do more harm than good?

Also, if I do end up draining the pool. should I try a chlorine wash before doing the acid? If so, What is the percentage of the liquid chlorine used for this?

Thanks

 

[JohnT]

The easiest thing to do is to check the stained areas by rubbing one spot with a trichlor puck and another spot with a vitamin C tablet. If trichlor lightens it, then high chlorine levels might help clean it up. If the Vitamin C lightens it, it indicates metal staining which requires another approach entirely.

 

[jblizzle]

Well, it depends on what type of "stains" you have.

- If it is organic, then higher FC and brushing will lighten/removing it.
- If it is metallic, then you will need to do an ascorbic acid treatment to remove the stains and then use a sequestrant to keep the stains from returning
- If it is calcium scaling (not really a stain, but can look discolored) due to high CH and pH, the acid washing is the quick solution, or you maintain a lower pH and with a lot of brushing can SLOWLY remove it (think on the months to years time frame not days to weeks).

So, you need to ID the problem before knowing the path forward.

 

[JT2006]

The easiest thing to do is to check the stained areas by rubbing one spot with a trichlor puck and another spot with a vitamin C tablet. If trichlor lightens it, then high chlorine levels might help clean it up. If the Vitamin C lightens it, it indicates metal staining which requires another approach entirely.

Tried the Vitamin C and nothing happened so it not metal staining.

 

[jblizzle]

Add some pictures. Does the stain feel raise / rough?
I am more inclined to guess calcium scaling than organics unless your pool was recently a swamp.

Try a puck and see what happens.

Post up a full set of test results.

 

[JT2006]

Add some pictures. Does the stain feel raise / rough?
I am more inclined to guess calcium scaling than organics unless your pool was recently a swamp.

Try a puck and see what happens.

Post up a full set of test results.

Ok I will do it tomorrow I am working tonight.

I'll post test results and some picks.

Thanks

 

[JT2006]

Ok I tested the pool this morning. First time I've done this so?

I've got the deluxe Taylor kit from Leslie's here are the numbers I got:

Chlorine is really high!

I recorded the FC at 5 although it was darker so probably more like 6 or 7!!

Tested for TC no color change so according to instructions (TC-FC=CC) would mean my CC = 0??

PH = 7.2

Total Alkalinity = 120ppm

I also took some pics of the pool stains

 

[jblizzle]

From the pictures, I would have really guessed metals. But, thought you had already tried the vitamin C. Have you tried a chlorine tablet for a few minutes yet?

You did not just buy that kit did you? Because it is not one of the Recommended Test Kits.
With the chlorine test, you really can not get a good enough value for FC or CC.

You also are missing results for CYA and CH.

How have you owned the pool and never tested the water in 5 months?

 

[JT2006]

From the pictures, I would have really guessed metals. But, thought you had already tried the vitamin C. Have you tried a chlorine tablet for a few minutes yet?

You did not just buy that kit did you? Because it is not one of the Recommended Test Kits.
With the chlorine test, you really can not get a good enough value for FC or CC.

You also are missing results for CYA and CH.

How have you owned the pool and never tested the water in 5 months?

I had a pool service until I cancelled them Monday.

I though as long as the kit used the Taylor chemistry it was ok? No big deal I did just get it but it was only $35 if I need to buy a better one I will.

I'm going to try the vitamin c and the chlorine tablet again and see what happens?

 

[jblizzle]

You may have multiple stains.

In the spa they look brown which could be organic. But in the pool there is the black/blue which could be metallic.

Very rare to find a good test kit in a local store ... which is why we generally suggest that it is ordered, with the TF-100 being the best value.

 

[JT2006]

You may have multiple stains.

In the spa they look brown which could be organic. But in the pool there is the black/blue which could be metallic.

Very rare to find a good test kit in a local store ... which is why we generally suggest that it is ordered, with the TF-100 being the best value.

Ok thanks for all your help. I tried the vitamin C didn't even touch it.

I drained the spa down just below the first step rubbed a chlorine tablet in a good area and I'm letting it sit there for awhile I will let u know if there any change

 

[jblizzle]

Wait, you want the Vitamin C and chlorine tablet to be under water. Not just dry sitting on the stain.

 

[JT2006]

Wait, you want the Vitamin C and chlorine tablet to be under water. Not just dry sitting on the stain.

Oh ok I will try again lol! Thanks