Stains on New Marcite

I had a gunite/marcite pool finished last October. The pool was filled with two truckloads (18,000 gal) of city water as we are on a well. I did add about 4,000 gal (22,000 gal total) from softened water inside my house. This is my first pool so this is all new to me. But over the past couple weeks I have read your site pretty thoroughly and have learned a lot. We had the kid’s birthday party right after it was finished in the fall and then closed it up. It is a SWCG pool, but the Intellichlor system wasn’t installed until this spring so the marcite had time to set. When the pool was closed up it was clean and when it was opened it had some minor algae, but pretty clean – no leaves or organic matter. The pool builder got rid of the algae with chlorine I presume as I wasn’t around when they opened it to add the Intellichlor unit. When opened there seemed to be some dirt staining on the 10’ wide Roman steps (darker brown, irregular pattern, worse on the top two steps). In addition to that there is a fainter intermittent bathtub type ring about a foot or two up from the floor. The water was never drained down to that level. Lastly there is spotty staining sporadically spread on the floor of the shallow end. That is grayish green in color and could be minor algae.

None of the stains will brush out and the stains on the steps are not metal as I did the absorbic acid test. I haven’t tested the wall or floor stains yet. I had Leslie’s perform an iron test on the water and there was nothing detectable. The good news is that the water is perfectly clear and I believe the chemicals are in good shape.

The builder has come out to look at the stains and said he could drain the pool and acid wash. Since I just paid $700 for the water in the fall and the builder just dumped in 600#’s of salt, I want to avoid that if possible. Not to mention the damage it causes to the surfaces. He is looking into other options, but I’d like to get the groups feedback and suggestions as well. Sorry for the long post, but I wanted t o be through as it is very frustrating to have a brand new pool that is dirty! Thanks for any ideas you may have.

22,000 gallon free form gunite/marcite, with sand filter and SWCG
FC – 3, CC- 0, PH – 7.6, CYA – 55, CAL – 250, ALK – 120, CU/Iron – 0/0, Phosphates - 0

+ What color is the INSIDE of your toilet tank? (look inside a toilet that is white.)
+ Buy a small bottle of Iron Out in the detergent section somewhere.
+ Put a couple of tablespoons full in a thin small snack baggie; remove the air and close. (Do NOT suck the air out -- Iron Out fumes are better not breathed!)
+ Take the bag underwater, and open it onto one of the dark brown stains. Use the bag to hold over the Iron Out, so the slurry can sit there a few minutes without being wash away or immediately dissolved.

Dark brown (coffee/chocolate?) stains on a pool with well water sound like possible manganese stains - but I hope not. Gray green 'stains' sound like plaster mottling, which is a finishing problem.

My pool builder suggested a commercial product (I don't want to give the name and be accused of spamming) that has a test kit for stains. I called that company direct and based on my explanation he said it sounds like calcium scaling and mineral deposits because when I opened the pool my PH was high (8+), which would cause the calcium to come out of solution and attach to the walls/steps. So I am going to pick up that test kit. Hopefully that confirms his theory or tells me exactly what it is and then we can treat it. He also asked if the stains were rough like sand paper and they are now that I went back and felt them, which also is consistant with calcium scaling.

I don't know what the treatment is for calcium scaling but hopefully it is fairly straight forward. I know it is pretty aggressive because you don't want to run it through the heater and I am pretty sure I don't have a heater bypass. So that will be a challenge.

Pool Doc thanks for responding. To answer your question - my house sat vacant from 2005 till 2009 when we bought. It also did not have a water softener. So the toilet tanks were very rusty when we bought. I have added iron out directly to the tanks and it cleaned them a lot, just not all the way. I have had my well water tested and the iron is at about .8 ppm, which .5 ppm or more will cause staining.

I will let you know what the testing confirms.

I think the Jack's Magic process works, but it can be VERY expensive on badly stained pools.

And, even if you use their process now, with the iron in your fill water, you're going to need to learn to manage the problem over the long term. Do this:

1. Get the Jacks' Magic test samples, or not. Your choice.
2. Put your pool info (volume, pool type(gunite), pool equipment make / model) in your signature (link in MY sig for that)
3. Read the test kit info page (link in my sig, again)
4. Get an OTO kit, ASAP.
5. Order a K-2006
6. As soon as you are able to test pH, begin lowering it with muriatic acid (instruction page link in sig)
7. See if what you have is residue from 'sand algae':

https://lh6.googleusercontent.com/-d...gae_09_HHH.jpg -- https://lh6.googleusercontent.com/-J...MG_2545-ed.jpg

Before clean up: https://lh6.googleusercontent.com/-d...gae_01_HHH.jpg

I did the test kit, which confirmed calcium scaling. I am going to follow Jack’s recommended procedure, which is to lower the PH and TA to below 7 and 80ppm. Turn off SWCG, add their sequestering agent and cleaning agent. Brush walls to make sure it is all in solution. Run filter for 48 hours while maintaining chlorine 1-3ppm.
Then once stains are removed and filtered (by sequestering agent), backwash and bring PH and TA back up. My question is, what should I use to bring it back up? They suggest using Sodium Bicarbonate to raise both PH and TA – no more than 4# per day. I asked about Borax and they said it works well to raise it and as a PH stabilizer, but it is toxic to animals and shouldn’t use it if I have pets that may drink the water. Which I have two dogs. How much baking soda or Borax do you think I’ll need to bring the PH back up?
Then the bigger question: Will keeping my PH below 7.8 prevent this from occurring again? Jack’s seems to think so. They said I could add their sequestering agent as a maintenance product, but isn’t required. Is there any issue with maintaining the PH at 7.2-7.4 range?

If they are using oxalic acid, it's possible that you may remove some calcium on your filter.

OTHERWISE, all you've done is re-dissolve it temporarily. This is the EXACT fallacy of most stain treatment programs I've seen: they hook you, and keep you there. You might want to call Jacks Magic back, and ask exactly how the calcium gets removed from the pool water. Tell them you understand how they are re-dissolving it, but that you want to know what happens to it, after it's in the pool water. If they fudge or hem & haw, I wouldn't bother their program. (Well, come to think of it, I'd rather you go ahead: I'm not sure I can help you remove those stains 100%. I'm not sure they can either, but if you go with their program -- and can't remove all the stains, you'll blame them, not me!)

You need to ignore their borax scare tactics, for two reasons.

First, borax doesn't combine with calcium to form scale; carbonates (bi-carbonate) DOES.
Second: unless your dogs drink a LOT of water from your pool AND you get your borates VERY high (> 50 ppm) AND you are planning to BREED your dogs . . . it's not an issue. It just affects their fertility, and it may be very slightly mutagenic, so that out of a million dogs drinking borax, you might have one more 5-legged puppy than usual.)

So do this:

1. Use their program to REMOVE the stains. I think it's as likely to get the stains up, as anything I can help you do.
2. Order a K-2006 (test kit page in my signature)
3. Test the calcium levels in your pool (before and after Jacks, if possible, but DEFINITELY afterwards)
4. Test the calcium levels in your FILL WATER (wanna know where it's coming from!)
5. Ignore their bicarb advice; use borax!
6. Tell us what your calcium levels are (before, after, fill) AND whether the scale was sand algae residue, or something else.

THEN, we'll be able to tell you that the problem is solved OR that now that you have the calcium back in the water you're going to have to remove it from the pool!

By the way, if your calcium levels are the same or higher AFTER their process, then they were before . . . you'll have just discovered that Jacks Magic is using a "return to me" strategy!

UPDATE: I used the Jack’s product per their recommendation. It did work well and took out all the major stains. It didn’t clear the very faint light grayish stain over most of the floor. But that is fine as it isn’t really noticeable by most anyone else. My calcium before was about 240 and during was about 450 and after is back to about 240. So I am aware that it took the calcium and staining off the walls and floor and then put only the calcium back on, which I am OK with because it is clean calcium.

Thanks for the update. I'm glad to have the info, and I'm glad it worked for you.

Do you mind listing exactly which products you used?

Thanks,

Ben

I used the test kit ($10) and ID'd the stain as calcium scaling. Then used 64 oz (2 bottles - $25 ea) of the magenta stuff and about 23 lbs ($35 / 5#) of the calcium scaling and copper stain remover. After a week I added 12 more onces of The Magenta stuff and will contunue to add a maintenance amonut for a few weeks. They have a written process in PDF form that is easy to follow. I can send it to anyone that is interested. It is not cheap, but was fairly successful.

OK, checking through MSDS:

Magenta Stuff => PAA, polyacrylic acid (calcium carbonate dispersant)
Stain Solution #2
(The Copper and Scale Stuff) => Sulfamic acid (interesting!)

Thanks (please check that what you used was "Stain Solution #2" or "Copper & Scale Stuff")

Ben