Please help with stains

[waste]

Hey all

I've got a pool with MAJOR stains that needs be opened by next Friday

The stains are all from over the winter (there were a butt load of leaves and pine needles in it because the cover wasn't put on until mid-November). My last day was Oct. 31 and though I had scooped leaves 2X/ week, I could see the 'tannin' stains starting. I checked with small pieces of tri-chlor to be sure that they would lift (and they did), so figured that I'd just have to shock the 'Bejesus' out of the pool this season to lift the all around stains.

OOPS! I was wrong :grrrr:

Even a kneehigh filled with cal-hypo barely lessens the stains- and the strange thing is that the slight help is where the kneehigh full of cal-hypo isn't sitting (the stain is 'full strength' where the stocking is touching the floor), but the surrounding area is lighter?

Setting a lemon slice on one of the stains also partially lifted the rust colored stain (in the spot I tested).

On what were obviously pine needle stains, in the hot tub, a gentle rubbing with a lime removed the stains, while cal hypo and tri-chlor did not work - though they did work on some other stains. I know pine needles are acidic - is it possible that their acidity breaks down the marcite finish and embeds both their "metal" stain and allows the tannin, from the other leaves to take hold in the 'weakened' marcite?


The stains on this pool are fairly universal, though 'splotchy', white in most of the floor, heavy 'light brown' in wide areas and really rust looking in a number of spots (looks like something ate into the plaster in ~ 10 spots - those areas are darker and look [I haven't gotten in the pool because it's only 55* ] more darkly stained than the rest of the floor/ walls.)

I know y'all want and need it so here are the specs and chem #s :

40,000 gal
Marcite finish
Cl > 20 ppm
pH 7.2
Alk 90
CH 175
CYA < 30
Temp: ~55*(I haven't adjusted too much because the heater will take it up to 80* by next Friday)


I appreciate any and all help :bowdown:

 

[JasonLion]

Those are sure sound like iron stains. The color is right, reaction to lemons is right, getting darker in response to high FC levels is right. Perhaps the needles are somehow raised the PH (not what I would expect) around them and caused iron already in the water to stain where they were lying.

Whatever happened, it seems like an AA treatment is in order.

 

[waste]

Thank you Jason! :bowdown:

Can I do it with muriatic acid? Back in the day, I did a couple of acid starts and 'no drain' acid washes. Can I just take the pool pH down to ? and brush it, to help get the stains off?

Please remember that I need (management wants) this pool open on Friday and I can't monitor it 24/7.

The pool is < 1 year. I forgot to mention that in the ~ 10 darkest spots, it 'looks' like the plaster/ marcite is pitted.

I guess what I'm looking for is a 1 or 2 day process (I'd prefer 1 day [8 hr] or 48 hr method because I'm scheduled to not work Tues and Wed. If I have to go in on my days off - the Gm Okayed it and the health and 'swimability' of these pools is a priority )

 

[JasonLion]

I don't recommend acid because it will affect the plaster lifetime to some extent, but that isn't the end of the world or anything, and you are right that it ought to get you back to "normal" a lot more quickly. I'm not 100% sure acid will work, because I'm not completely sure what those stains really are, so I'd try a localized test with dry acid in a sock or muriatic in a pipe just to confirm that acid works first, which shouldn't take very long at all.

 

[Poolschoolgrad]

Ted

Here is how I treat vinyl and fiberglass steps that have brown stains from Iron. You could test it on one of the darker spots on the Marcite finish.
Natural Chemistry makes a produce called Stain Free. It is Ascorbic Acid. Pour about 1/4 pound of the product into a slightly used sock. Rub the sock on a stained area for a few seconds to see if the stains begins to lift.

For stubborn stains, I have used oxalic acid.
United Chemical has 2 products called Pool Stain Treat and Super Stain Treat. These oxalic acid based products are stronger than Ascorbic acid.

Both of these products will lower the chlorine, alkalinity, and PH of the water. After you adjust the alk and PH, then slowly increase the FC to target level. If you increase the chlorine level quickly, the stains seem to reappear overnight.

The Oxalic acid product also acts as a sequestering agent to help keep the stains away for a short period of time. I regularly add Jacks magic purple stuff to my salt pool to prevent iron stains. For the plaster finish I would use Jacks magic pink stuff.

PSG

 

[waste]

Ted

Here is how I treat vinyl and fiberglass steps that have brown stains from Iron. You could test it on one of the darker spots on the Marcite finish.
Natural Chemistry makes a produce called Stain Free. It is Ascorbic Acid. Pour about 1/4 pound of the product into a slightly used sock. Rub the sock on a stained area for a few seconds to see if the stains begins to lift.

For stubborn stains, I have used oxalic acid.
United Chemical has 2 products called Pool Stain Treat and Super Stain Treat. These oxalic acid based products are stronger than Ascorbic acid.

Both of these products will lower the chlorine, alkalinity, and PH of the water. After you adjust the alk and PH, then slowly increase the FC to target level. If you increase the chlorine level quickly, the stains seem to reappear overnight.

The Oxalic acid product also acts as a sequestering agent to help keep the stains away for a short period of time. I regularly add Jacks magic purple stuff to my salt pool to prevent iron stains. For the plaster finish I would use Jacks magic pink stuff.

PSG

Thank you!! I've tried lemon wedges and stockings full of cal hypo with inconclusive results (There looks to be some lifting, but hard to tell) the one place I put the sodium bisulphate on came out WHITE in one area, but it also looks like a chunk of the plaster came off

I'm beginning to think I might just be better off draining the pool and acid washing it . One way or the other, I want to have this pool ready by Friday, or Saturday AM and it will take the heater 3 days to bring it up to the 80* we want.

Given my time frame, I need to make a decision tomorrow. Another option is trying the 'metal out' products that the PB sells (they are Haviland stuff, and I have no experience with them) but I need to be sure that the pool is operational by Sat A.M., at the latest.

Thanks for all the advice