Possible "low alk treatment" to fix stains?

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Albromyle

0
Sep 28, 2014
8
Corona, CA
Hello, I have some stains that I think might consist of calcium. I also know I have a small amount of yellow mustard algae, but my plan with that is to do a minor shock to the pool to fix that issue.

My main concern however is the stained dark splotches that I have on my pool walls and floor. I did some of my own research and realized that the potential fix is called a "Low Alk Treatment". I would reduce the PH to a low amount, possibly around 2.0, while keeping the TA down in the 20-30 range, and let it do that for about 48 hours.

However, is this even my problem based off the pictures you guys can see, or is it a different? Essentially every time I try to brush it, it won't come off, so I'm figuring it's embedded "underneath" the plaster, like a moisture of some sort. As soon as I bring the ph and alk to a low level, the plaster does a chemical reaction to "release" it, and then I use my pool pump/filter system to draw in all that stuff, cleaning it out about every 12 hours for 48 hours.

Now is it recommended to leave the pool pump running for 48 hours on the ENTIRE process of the low alk treatment, or just when I need to collect the released contents from underneath the plaster's surface layer? I've had this pool since 2006, and have had a small but steady buildup of the stuff shown in the pictures (the dark grey/light grey splotches, not the yellow). Another thing that I notice is that it is MUCH more visible to see the splotches and stains when it is cloudy and when it is not in direct, bright sunlight. It becomes less noticeable when it is sunny and bright without hindrance (aka no clouds, etc).

The pictures are taken when it is bright and sunny, it was cloudy yesterday but I did not manage to get pictures then. I would say that the problem I have isn't enormous like what I've seen with other people's problems, but it is definitely an issue that I need to get fixed.

Thanks, and appreciate any help in advance!

Please keep in mind that when it is cloudy it looks more grey-ish then it does now.

http://imgur.com/gvGw2Jr,WRWRUOp#0

Better pictures of the overall problem (taken during late day): http://imgur.com/IPUjyMj,33jUEkE#0
 
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I'm no expert, but I think a PH that low would be very harmful for your pool and equipment. Have you searched the forum for alternative methods? Do you have a full set of reliable test results?

If you read pool school, you will see they recommend SLAMming the pool and then bumping it up for a day after you pass the criteria to end when you have mustard algae. But you would need to provide more info to help us help you figure out if that's even the problem to begin with.

Welcome to the forum, and hopefully someone with a tad more expertise will come along to assist!
 
I'm no expert either, particularly with plaster, but that treatment sounds downright corrosive IMHO. But perhaps hats what they actually do when they do an acid wash, which I've read can be harmful to your plaster.

Re the yellow...does it brush off, or is it stain-like too? if stain-like, first test the stains using a vitamin c tablet. If holding a vit c tablet to it causes it to lighten, then ascorbic acid will lift the stain, and you may instead want to read up on and try the AA (ascorbic acid) treatment for at least that part.

Maybe you'd get more responses if you reposted your question with something like "Help with gray mottling, plaster scaling" -- your title might scare anyone off...nobody here is likely to want to encourage you to drop your TA and ph that low ;)

And do you have a heater? If so, it would need to be bypassed...

The best course here would be to post accurate test results so folks could help you determine what kind of CSI you're at, how to better balance to avoid further scaling, and then how to remedy. It all starts with the testing.
 
Yea, the yellow is not a problem, I know hot to fix it, it's easily brushed off, and I know SLAMing the pool would fix that. . I've also already read the pool school, so I know SLAMing the pool would not work for gray-ish type of scaling. I'll see if I can post some test results soon.

Thanks for the responses, I'll keep you all notified once I get the results.

I'll also make a repost under a different title to see if that also gives me some more results.
 
You didn't post any details on your pool but using PoolMath, my 20K gal pool would require 44 gallons of acid (approx $350) to bring it down to pH of 2. Maybe PoolMath isn't the right tool to calculate this extreme pH shift but on the face of it, this seems like a way over-the top, bizarre and potentially destructive way of trying to solve your problem - whose cause hasn't yet been clearly identified. You really should post your research sources for this process if you'd like a serious assessment of its potential benefits.

EDIT: With a little more time to think about this I'm guessing there was a mis-print or mis-type and the pH was intended to be stated as 7.2 or 6.2, but not 2. Those would be a sane pH targets for this process and also might allow you to "...keeping the TA down in the 20-30 range...."
 
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PoolMath is NOT accurate for large pH swings (acid or base additions). Also, it is impossible to keep the TA in the 20-30 range and have the pH at 2. The TA will measure as 0 in the TA test when the pH is 4.5 since that is the transition point for the indicator dyes in the test. Very low pH is very destructive to plaster and not recommended. Traditional acid washing is a destructive process -- the smoothing of the plaster coming from literally removing surface layers of it.
 
So I did some tests that were very similar to the recommended TF-100, mine being the Taylor K-2005.

These are the results I got.

FC: 6.0
PH: 7.8
TA: 150
CC: 0
CH: 500
CYA: 50

Anything of note within these tests that could be the culprit? I'm going to go off the bat and say that the CH is off the charts, and I know Calcium can POSSIBLY cause the stains that are shown in the pictures in my original post. I'm sure it needs to be lowered down (thus draining the pool, which I prefer if I can somehow avoid due to being in California, and having to worry bout those ridiculous water costs now). My alkalinity seems rather high too, seemingly double then what it should. My FC is a 6.0, so I'm thinking the reason for that is because I run my SWG Chlorinator at 90%.

What I find odd though is that the pool does not necessarily smell like chlorine would smell at 6.0, so I'm also really hoping my test kit has not gone bad. I've taken very good care of it, keeping the lids tight, and in a cool, dark place for around a year now.

If I do need to drain the pool, could I use the water from my nearby hose to fill it back up?

I'd prefer to not go to my "local pool guy" b/c I have a feeling their tests can be inaccurate.
 

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With metal staining, a good place to start is to lower your ph to 7.2 and keep it below 7.4. That alone my help further staining immediately. I'll let others address what to do about the calcium...my vinyl pool means I know nothing about managing it ;)
 
If you haven't already, you should become familiar with PoolMath (one of the tabs on most every site page). If I plug your numbers in, the positive CSI that it returns suggests calcium deposits are likely. You should definitely lower your TA and keep your pH below 7.8 on a continuous basis. Play around with PoolMath and read Pool School for more guidance.
 
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