Stains on White Plaster (Saltwater Pool)

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PoolGai

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Jun 3, 2011
18
Hello All,

I've been struggling with an issue for a few days now and, after getting mixed advice from Pool Stores, etc, I thought I'd turn to a forum to see if anyone has experienced this issue or could offer up some new ideas.

Basically, I opened my pool over the Memorial Day weekend and it was green. I lacked some things in the pool closing, regardless, the water is sparkling clear now. I've tested my water and it is balanced. Obviously I have some residual green algae stains (I've been unable to confirm if it's black, but I didn't see any 'heads', so I'm assuming it was only green). The stains do not react to acid, so I know they're organic - some have bleached out when using shock that was not brushed immediately.

For 3 days in a row, I shocked the heck out of my pool, both the FC and TC were > 10. You'd think with chlorine levels this high it would remove the stains, but it isn't. It's hard for me to tell if the stains have lightened at all, but I do notice that when I brush with a steel brush, I do see some brown dust come up - I'm assuming this is dead algae?

1) Should I keep shocking and maintain very high levels of chlorine in an attempt to bleach these stains out? Will they ever bleach out completely?
2) Is there anything else I can do accelerate this process? I don't believe there's any magic solution that will rid these stains.

Here's a link to my Google Picasa website to show you what I'm talking about:
https://picasaweb.google.com/108909815950832073991/PoolAlgaeIssues?authkey=Gv1sRgCITvq92At-f2NQ#
I would greatly appreciate any insight or advice you guys could give me.

Thx,
Zach
 
Welcome to TFP!

That is very likely organic staining. You can confirm that they are organic by putting a trichlor tablet on a stained area for a minute or two. The stains should lighten where the trichlor tablet was. Organic stains fade over time, more quickly at higher FC levels. Depending on the stain this can sometimes take a while.
 
Thanks for the warm welcomes, here are my results (prior to adjusting the Tot. Alkalinity and pH from yesterday:
CYA 77
TC 10
FC 10
pH 8.1 (now 7.4)
Tot. Alk 77
Tot. Hardness 175
Salt 3.2
No iron, copper, manganese, iron, etc.

I did place a chlorine puck on one of the stains, but it barely faded...ascorbic acid does nothing. I'm to the point where I don't want to keep super shocking the pool and actually use it, but I don't want to mess up the process of removing these stains in the meantime.
 
You can stop shocking if you want. If the trichlor had very little effect, then shocking isn't going to do anything quickly either. Stains aren't like algae. If you stop treating them the only thing that happens is that they don't go away as quickly.
 
Gotcha, just to be clear though, there's nothing else I should be adding to help/aid in the stain removal..whatever the stain is? Clearly the stuff on the walls is a result of the water line fluctuation throughout the winter as I pumped water out and water/snow/etc filled it back up again. The rest is def. a result of leftover algae. I'm going to try a pumice stone tonight on my bench and steps to see if that helps...I just don't want my white plaster ruined and I'm not up for a drain & scrub.
 
Alright, and you saw my pics, did they help confirm?
Also- someone recommended Natural Chemistry's Pool Perfect/Pool Magic/and/or a Stain & Scale. I don't think any of these are going to make it magically disappear but I know I haven't added a stain & scale this year, is that at all beneficial with a salt water pool?
 
Neither of those is likely to help, thought there is a small chance Pool Perfect might help since we aren't 100% sure what is happening.

Pool Perfect is an enzyme treatment that helps chlorine break down oils and other organics that it has trouble breaking down on it's own. It is normally used when there is a lot of suntan lotion floating on the surface of the water. Stain & Scale helps prevent iron stains and calcium scaling. It isn't going to help here, since the stains are already in place.
 
Well I think I've finally narrowed it down, perhaps you can tell me if my logic is correct? Ascorbic Acid/Dry Acid in a sock did not remove any stains; A chlorine puck left for hours did not remove any stains. Using anything to brush other than a pumice stone does not work. I think my problem is scaling due to high pH with dirt trapped underneath. My system consistently runs on the higher side of the pH scale, not sure if it's because it's only 2 years old, saltwater, plaster or a combo of all 3, but I'm certain over the winter it was high.

That being said, besides keeping the pH down as close to 7.2 as I can, will adding any kind of "de-scaling" product help to take off whatever is on top so that my chlorine will kill the rest (along with brushing)? I read about a product by Natural Chemistry called ScaleFree in addition to one by BioGuard called Scale Inhibitor -- none really give me a great explanation of if the products will work for my situation or not. I'm going to call and ask about them in more detail as soon as some stores open this morning.

Does this make sense/sound logical?
 

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If the stains are scaling, try using a sequestrant optimized for calcium like Jack's Magic The Blue Stuff, keeping your PH and TA levels low for a couple of weeks, and brushing with a stainless steel brush.
 
Ok - should I be able to see scale or can it be transparent and trap dirt underneath like I'm describing?
Either way I think I'm going to just give this stuff a try, I can't see what else could be the issue. I'll add 3 qt's of the Blue Stuff and see what happens. 1qt per 10,000 gallons, sound good? I appreciate all of your help/advice.
 
I got most of the scale/dirt underneath off by keeping the pH between 7-7.2 while adding Jack's Magic Magenta Stuff. I kept the pH lower for about 4 weeks, while brushing with a wire brush as much as possible, and most of the scale was removed and filtered. I still have some slight discolorations on my plaster, but it is no longer rough. I imagine the only way to rid this is by doing an acid wash, which I've decided against unless it gets worse.

Hope this helps.
 
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