Black spot after Vitamin C tablet (Complicated)

[MarkGLN]

To prevent scale from forming on the pool walls maintain your CSI between -0.3 and 0. Poolmath will calculate it for you. Adjust ph, ta and ch to move the number. More here, Pool School - Calcium Scaling

Eventually I hope to replace some water, but it will be spread out over a period of time. That will help reduce the CH. The pH and TA will be taken care of with muriatic acid.

I am curious though if anyone knows the ingredients in Beautec. It reportedly reduces scaling and controls calcium and doesn't contain phosphates.

http://www.mcgrayel.com/beautec.html

I don't care to introduce any more chemicals into the pool, but I believe one of the earlier criticisms of these descalers was that they contained phosphates.

 

[JoyfulNoise]

It's just a sequestrant but it's main ingredient is likely polyacrylic acid (PAA) as opposed to HEDP. So when it breaks down, it releases calcium and forms carbonates and dissolved CO2.

If you add it, it will help to control scale but you could throw off your CH test because it may bind the calcium so strongly that the R-0011L dye will not react with it.

 

[pooldv]

Well, those are some of the most useless product data sheets and MSDS I've ever seen. It is a purple liquid with a slight odor that probably won't kill you if you drink a little. If they aren't willing to tell you what's in the bottle then I wouldn't be willing to put it in the pool. Yes, one of the byproducts of a good sequestrant is phosphate.

 

[MarkGLN]

It's just a sequestrant but it's main ingredient is likely polyacrylic acid (PAA) as opposed to HEDP. So when it breaks down, it releases calcium and forms carbonates and dissolved CO2.

If you add it, it will help to control scale but you could throw off your CH test because it may bind the calcium so strongly that the R-0011L dye will not react with it.

That doesn't sound too bad. I have trouble with the CH test as it is. If that's the only downside, I wouldn't have any qualms about trying it.

But I also agree with pooldv. It there's not even a hint of what's contained in the product, why should we trust it? Then again, one could say that about Jack's Magic products and yet those products are well-respected.

 

[JoyfulNoise]

Actually, in looking at the MSDS I noticed it says the pH of the Beautec is around 11. If that's the case, then it's not PAA. PAA would create an acidic solution. So it makes me wonder if it isn't just something like sodium tripolyphosphate. The STP would not necessarily add orthophosphates to the water because they would sequester and then precipitate the calcium out of solution as calcium phosphate. That probably works well enough in a vinyl pool but could be bad in a plaster pool as there's no way to ensure that the calcium will only scale out in the filter.

Heed Danny's advice, if you don't know what it is, don't add it.

PS - Jacks Magic is very open in their MSDS's for their products. Their chemicals are either HEDP or PAA.

 

[MarkGLN]

Heed Danny's advice, if you don't know what it is, don't add it.

Yep. That's what I'm going to do, and so far so good.

PS - Jacks Magic is very open in their MSDS's for their products. Their chemicals are either HEDP or PAA.

Thanks for the correction. I'm glad their reputation is based on transparency.

 

[MarkGLN]

Question about oxidized copper

I've posted before about how our pool has a lot of green stains, and I thought some were organic and some were copper. I was able to "wipe away" or lighten many of the stains using a mechanical stain removal product that is not pumice, but is likewise used to rub away stains and scale. It's worked very effectively so far.

The next issue is will the stains come back? I decided I'd try the Culater product which is designed to trap metal ions and completely remove them from the water. The trouble is, I've never registered any metals in the water. I assume that's because the metal was on the pool surface.

Now the situation has changed. The scale and presumed copper has been rubbed away and is going into the filter. My thinking is that if the chemistry becomes unbalanced, the copper can leave the filter and return to the pool as stains. The Culater product would be designed to intercept that process.

However, I just read, or rather re-read that Culator only works on metal ions not oxidized metal and I believe the greenish stains indicate oxidation has occurred.

The questions I have then are:

1. If oxidized copper embedded in scale has been rubbed away from the surface and directed to the filter, can that copper get into solution again as an ion?

2. Do I even WANT the copper to get into solution as an ion? (The main benefit being that Culater can go to work on it.)

3. Or is it better that the copper remain in its present state and it will eventually get taken out of the system when the DE Filter is cleaned.

 

[JoyfulNoise]

Re: Question about oxidized copper

1. If oxidized copper embedded in scale has been rubbed away from the surface and directed to the filter, can that copper get into solution again as an ion?

Yes. If the pH gets too low (<7.0), then the cupric ion (Cu²⁺) becomes more stable in solution. So if you had trapped metal in your filter in the form of an oxide, persistent low pH would convert the oxidized solid metal back into it's water soluble form.

2. Do I even WANT the copper to get into solution as an ion? (The main benefit being that Culater can go to work on it.)

No, you don't.

3. Or is it better that the copper remain in its present state and it will eventually get taken out of the system when the DE Filter is cleaned.

Generally speaking, if you have scale (calcium and metal solids) in your filter, you should backwash your filter or tear it down and clean it out. Leaving scale inside the filter just leaves you open to having the metal ions return to solution.

As for the CuLator product, I have always been very, very skeptical of their claims. While their polymeric ion exchange resin is based on real science, the implementation of it (a bag of stuff sitting in your skimmer basket) makes no engineering sense whatsoever. In order for an ion exchange resin to work, 100% of the water must flow through the resin in order for there to be the necessary contact area and time for exchange to occur. If you think of a home water softener which operates with a sodium/calcium ion exchange resin, ALL of the water flows through the resin bed and no water is allowed to bypass the resin bed. With a bag of beans in the skimmer, most of the water is simply going to flow around the CuLator bag making it highly inefficient.

Also, from a chemistry standpoint, ion exchange resins do not typically discriminate well against any particular type of ion. So, the ion exchange resin will capture ANY divalent metal cations - Ca²⁺, Fe²⁺, Cu²⁺, Mg²⁺, etc, etc. In fact, it is well known that many ion exchange resins have a higher affinity for calcium ions than they do for transition metal ions. So, just based on the fact that most pool water has hundreds of times the concentration of divalent calcium ions in solution relative to any metal ions, the CuLator will probably become saturated with calcium well before it captures any appreciable amount of metal ions....

Just my 2 cent opinion....

 

[MarkGLN]

Re: Question about oxidized copper

Thanks Matt.

As for Culater, don't worry, I consider it experimental. I don't mind paying 20 bucks for something that may (or may not) work. My expectations aren't high, but my curiosity is.

Plus, it wouldn't be such a bad thing if Culater sucked up some calcium. My CH is in the 700s, which is way too high.

 

[Swampwoman]

Re: Question about oxidized copper

Greetings, Mark. I've not personally had good luck with culater, likely for the reasons Matt outlined.

Have you tried to get a read on your copper level? If its approaching .3 ppm, save yourself some hassle and do a partial drain if you're able. Then control the rest with sequestrant.

Do note though, that if you use a sequestrant like Metal Magic when you have high ch, you will get a few days of cloudiness until it filters out...but that may help on the ch level as well

 

[duraleigh]

Please keep all your posts under this one thread.

Where is N/A?

 

[MarkGLN]

Re: Question about oxidized copper

Have you tried to get a read on your copper level? If its approaching .3 ppm, save yourself some hassle and do a partial drain if you're able. Then control the rest with sequestrant.

I've recently tried testing the copper level and it's either nonexistent or very low. There are a lot of questions concerning what has happened to the pool which is why I'm having to make educated guesses. The upshot of my guesswork being that there is/has been a combination of scale, copper and organics. The guesswork is based on the following:

* The green and blue-green color of the stains (indicating copper + organics)
* The high CH level (scale)
* Obvious rough plaster in places (scale)
* The oldest stains mirror where plant debris fell/settled in the pool (organics)
* The dark-then-light reaction of one stain to the Vitamin C tablet (copper)
* The copper plumbing in our system (copper)
* The fact that PG ran our pool at about 6.8 pH and one pipe eventually was so corroded it had to be replaced (We're now in agreement to keep it at 7.2) (copper)
* An incident which I still don't know what the reason was, but PG put something in the pool and shortly thereafter, there was both an algae bloom and green water. I've been thinking the green water was copper rather than algae since the limited algae we've gotten in the past has been powdery mustard algae that hasn't affected water color. (organics from algae + copper)

I may be wrong, but most of the evidence points to copper being in the pool in the past, and possibly still in the pool given that we still have copper pipes. However, I can't pick up the copper in any tests and we've been keeping the pH in the 7's.

Do note though, that if you use a sequestrant like Metal Magic when you have high ch, you will get a few days of cloudiness until it filters out...but that may help on the ch level as well

I've been wondering whether I should use a sequesterent when I can't get a copper reading in the water. That's partly why I decided to try Culater. Twenty bucks for a one-month supply seems like an inexpensive experiment (but may seem ridiculous in light of the zero/near-zero copper reading). Draining the pool is not an option at this time since we spent a fortune getting the pipe placed as well as in water bills when the pipe was leaking. We did get a partial replace of the water, however, as part of the pipe-replacement process.

The pool is very old and will eventually need to be replastered. In the interim, I'm basically trying to make it as aesthecially appealing as possible without spending too much money.

So, the question that comes out of all this is do I need a sequesterent given that there does not appear to be detectable copper in the water at this time.

 

[Swampwoman]

I'm going to circle back on a few things as fodder for thought.

First off, how much is your pool guy costing you? His ignorance on chemistry basics may have cost you plenty and a good trade might be to take over the pool management and spend the money on the partial water change after a treatment since your ch is also high, assuming your fill water isn't as high.

For the existing stains, another option is Jacks stain test kit just to confirm the nature of the stains even though you've determined that due to the copper pipes you don't want to use jacks stain stuff. One of the stains you reported was new, so in your shoes, i'd still be treating the water as suspect.

But if you want to spot treat the stains, you need either to buy or invent a tool to deliver acid, preferably MA, to the specific spt. Purity Pool tools that I linked to prior have either an underwater kit or a spot treatment tool that's pretty effective at this. You could also (wearing gloves) take a spot-sized bowl with a large sponge in it, soak sponge with MA, cover with something that can be slid off easily, turn bowl upside down on stain and weight with a brick...messy and a pita...which is why I bought the Purity spot tool

You mentioned $20/mo for culator. I'd put that $20 toward sequestrant instead once you've spot treated the stains ... That would just about cover maintenance doses.

 

[MarkGLN]

You mentioned $20/mo for culator. I'd put that $20 toward sequestrant instead once you've spot treated the stains ... That would just about cover maintenance doses.

I already have the Culator in, so we'll see how that plays out.

I've seen so many sequestrants mentioned on this forum, that I have analysis paralysis! I'd appreciate any recommendations. A SINGLE recommendation would be best. I'm assuming there are no adverse effects of sequestrants. I do know that they dissipate in any case. Which brings up another issue... Am I a slave to using a sequestrant for ever and ever until the day the remaining copper pipes are removed and the water drained?

As for the other things you mentioned, they are under consideration, but I think the sequestrant is the best start, given that I've already removed some stains.

 

[pooldv]

Copper plumbing isn't a problem as long as PH is maintained at 7.2 or higher.

Here is a recommendation for a not quite single sequestrant. But, it should get you going in the right direction.

Sequestrants based on HEDP, phosphonic acid, or phosphonic acid derivatives are the most effective. ProTeam's Metal Magic and Jack's Magic The Pink Stuff (regular), The Blue Stuff (fresh plaster), and The Purple Stuff (salt) are some of the top brand sequestrants. There are also other brands with similar active ingredients, some of which are noticeably less expensive.

 

[MarkGLN]

Here is a recommendation for a not quite single sequestrant. But, it should get you going in the right direction.

Sequestrants based on HEDP, phosphonic acid, or phosphonic acid derivatives are the most effective. ProTeam's Metal Magic and Jack's Magic The Pink Stuff (regular), The Blue Stuff (fresh plaster), and The Purple Stuff (salt) are some of the top brand sequestrants. There are also other brands with similar active ingredients, some of which are noticeably less expensive.

I think I'll go with Metal Magic. Reading about it, though, it appears to also be a metal stain remover and involves a treatment of raising the pH, running the filter 24 hours, backwashing, and a possible side effect of milky water. I'd like to avoid that if I can for now and just use MM as a sequestrent in a routine way not involving 24-hour filtering, backwashing, etc. Is that possible?

Also, I believe I read that MM lowers the pH and that's why they first recommend to raise it. Could I use MM as a partial replacement for Muriatic Acid to keep the pH around 7.2? PG has learned from his past mistake of running the pool at 6.8, but now he's very conservative with the MA and the pH rises shortly after his visits. It would be nice if less than a full dose of MM could be added between his visits to serve both the sequestrant role and to keep the pH from drifting up. (I've mentioned previously that my wife still isn't sold on us keeping MA on the premises, so I'm trying to find workarounds.)

 

[Swampwoman]

It does somewhat lower ph...by a wee bit, not a ton. So does Jacks in a smaller increment.

The directions for using MM ARE already the instruction for using it as a sequestrant. If your CH is high, you will not likely avoid the clouding and need for backwashing. That is the nature of stain and scale control and is not a bad thing.

 

[MarkGLN]

It does somewhat lower ph...by a wee bit, not a ton. So does Jacks in a smaller increment. The directions for using MM ARE already the instruction for using it as a sequestrant.

Okay, thanks. I didn't realize that. I thought sequestrants were just something you poured in and forgot...until the following month or so.