Tried ascorbic treatment, but pool needs more

[trichards]

I tried the ascorbic acid treatment and it took a few days (be patient) and did lift some of the stains, but not enough for my liking. So, I'm going to drain and acid wash the pool to see if I can remove more of the stains. My question is when I did the ascorbic treatment I put in Jacks purple magic (I have salt pool) and that kept the metals from falling and staining the plaster for about a month and then stains started to reappear. So, after I do the acid wash should I continue to treat the pool with Jack's purple on a monthly basis? I'ts a little pricey. Any advice would be great!

White plaster pool
Salt
15000 gallons

Trevor

[PoolDoc]

Better hold off.

Ascorbic acid and HEDP (Jacks Magic Purple . . . or Blue or Pink) both do the same thing: help redissolve metals, and keep them in the water. Ascorbic acid is better at re-dissolving metals; HEDP is better keeping them dissolved. But, with both THE METAL REMAINS IN YOUR POOL! It's just in the water, rather than on your pool's sides. And with both, the effect is temporary.

Acid washing does remove metals that were on the walls . . . by removing part of your wall! The muriatic acid dissolves some of the marble aggregate (calcium carbonate), and puts it, plus the metals that were on that part of the wall, into the 'wash' water, which is hopefully then taken somewhere else. But, in the process it leaves your pool's walls rougher and more porous (which is why you do it before you re-coat with more plaster), and also more susceptible to stains. You don't want to acid wash more often then you have to: the ideal number of times to acid wash your pool is never!

Here's the kicker: acid washing ALSO does not solve your problem.

Why? Because your problem is that metals are getting into your pool's water. And you cannot solve your pool problems with metals till you've done all of these three things:
1. Found out what kind of metals are staining your pool;
2. Found out where that metal is coming from; and
3. Stopped it from continuing to enter into your pool.

Your other alternative is to acid wash, wait till it turns whatever color it turned now, acid wash again, repeat . . . and then re-plaster and start the cycle over.

[trichards]

Ben
Since I'm not sure about what kind of metals I have how do I go about this? I got some blueish patches in some spots and the walls have a light brown tinge to them. When I did the ascorbic treatment the floor got a little cleaner and so did the walls, but the blueish stains seemed to remain untouched. So how do you go about figuring out where the metals are coming from? I have a pool heater (raypac) not sure if the heat exchanger is copper and I all of the screws in my lanai are rusting, so it's possible some might be coming from that. I'm in the middle of replacing the screws right now.

Also, if I understand the reading I've done on the site the metals will always remain in the pool, so what does one do if this is continual problem? Do you keep adding sequesterant on a monthly basis. What if it's in my water supply? We have city water not well?

Thanks for the advice

[PoolDoc]

OK.

Metals come -- usually -- from four places:

1. Well water --> iron or manganese.
2. City water pipes --> iron
3. Deteriorating pool equipment, due to mismanaged pool chemistry --> iron or copper
4. Copper algae treatments & 'mineral' or 'ionizing' pool gear --> copper

Usually, brown = iron or organic stains (oak leaves), and blue or green-blue = copper.

It sounds like we can rule out #1. But from where I sit, 2 - 4 remain possibilities, that have to be ruled out. Once you have eliminated all the metal sources, THEN you can see what it takes to clean up what you've got. That way, you won't have to worry about a re-occurrence.

You'll need to ask your water company about #2 -- their service manager will know, even if no one else does. But, #3 and #4 are all in your court. You'll need to

1. ID any metal pool equipment in the flow stream: metal pump, heater, ionizer or mineral product, etc. You should also check your lights, if any, for corrosion.
2. You need to check your CHEMICALS for copper; it's not only in algaecides these days, but also in trichlor tabs and other places you wouldn't expect. However, it's always on the label, though in fine print.
3. You need to check to see if there are any chlorine feeders UPstream of pool metal components, like tablets in the skimmer, an erosion feeder or a SWCG upstream of the gear.
4. You haven't mentioned any chemical measurements, so I'm guessing you don't do a lot of testing, and may depend on your pool store. You need ACCURATE measurement levels on your pool -- this testkit information page (http://www.poolforum.com/pf2/showthread.php?14994) explains, and has pictures as well as Amazon links if you want to order there. Right now, you need a K-2006, and a salt test kit, if you have a salt system. You need to get a K-1000, or better, a local equivalent, and check your pH NOW, and make sure it's between 7 and 8.

Once you've done those things, we'll have a basis to figure out where your metals came from, and how to stop it. Replacing rusty screws over the pool is a good idea, too. Don't add any more ascorbic acid; you can't have chlorine and ascorbic acid in the pool at the same time -- they destroy each other. Continue to use HEDP -- but no more than the label recommends -- while you're collecting information. HEDP sometimes removes stains over time, and it will prevent new ones from being deposited.

You can order copper or iron testkits if you like, but they won't necessarily help -- we're not sure the copper kits will measure iron in the presence of HEDP, and iron tends to come out of the water, and land somewhere, pretty fast.

Anyhow, once you have your data, post it, and we'll go from there.

BUT, if you find obvious problems, like chlorine the skimmer, or upstream feeders, or pH tool low, fix those ASAP. You can use a floater for trichlor, and can raise your pH with borax from the detergent section of Walmart or where ever.

Good luck!

[trichards]

A little background on the pool. We moved in about a year ago and it had these stains the pool was cared for by local pool company, so not sure what they put in the pool. When I took over the pool I chlorinated with bleach and used baking soda for ph & akalinity. I changed the pool to salt and I have a pentair intellichlor system & automation panel and I can monitor the PPM of the salt from the panel. Do I still need the salt test strips? SWG is plumbed after the heater.

I have had the light out to change the bulbs and don't remember any corosion on the light.

I do test the water and add acid weekly to keep the ph in the 7.6 range and the alk is 80ppm. Chlorine is low now in the 1-2 ppm it was much higher 4-5 ppm prior to the ascorbic acid treatment. I'm using a kit bought at Home Depot. I will take some water in and have it tested for copper Friday or Saturday. I have never put any algecide in the pool or chlorine tabs in.

Pool pumps are plasitic housings.

I will get a new test kit shortly and I will call the water department on Friday.

Any other further advice?

Thanks for your help!!

[PoolDoc]

So the stains were present WHEN you moved in, and haven't gotten worse? If that's the case, it may be prudent to see what you can do to remove them.

If you are not adding copper, and are not getting new copper stains . . . you don't need a copper test. In any case, a copper test is not going to reliable, because you probably still have HEDP in the water.


Getting a salt test is also optional. If you'd like one, that's fine. But it's not going to be essential, or help you remove the stains.
Getting a K2006 is necessary, because (a) you need to get away from pool store tests, & (b) you need to be able to test your CYA levels, and accurately test your chlorine levels.
Getting borate strips would be helpful, because dropping your carbonate alkalinity (baking soda) and replacing it with high CYA (per Pentair) and high borates make your pool less conducive to staining.
You will need to maintain calcium levels, to protect your plaster.


But, a pH of 7.6 is not going to corrode your heater.

So, for now, keep your pH on the low end of the scale; avoid adding bicarb; get a K2006; get borate strips if it doesn't push your budget; and continue to use HEDP per the bottle label.

By the way, if you are considering acid washing, simply draining, treating the stains directly, and then pressure washing may be more than enough . . . and not nearly so hard on your pool.