Fiberglass Pool Metal Staining...

Gents,

I purchased an existing home in December of 2013 and inherited a fiberglass pool.

Pool stats:
-18K gallons
- Chlorine
- New: Heater and filter (sand) in 2013

So it was un-opened for a year or two, after opening the pool this year it obviously took sometime to get everything sorted out and the only remaining obstacle is the metal staining (tested with vitamin C tablets and it promptly responds to Stain Free, etc.).

I've successfully treated the metal staining with "Stain Free" + "Metal Free" followed by a backwash within 48 hours, all while the chlorine is less than 1.0. The pool will stay stain free for 10-14 days and then the stain will return slowly and increase in color until it is fully visible (nearly original intensity). So I can get the stain to lift but the metal is somehow re-introduced. I've tested the tap-water and it is metal free, the heater does not have a bypass but the predominate culprit seems to be iron vs. copper.

So what is the source? I took a photo of our pool into the local pool shop and they called the "Stain Free" representative. Our pool is a bit unique and is built into a small hillside, two sides of the pool are protected by a sloping retaining wall (ranging in height from 6"-36") built of red-pavestone pavers that rise directly from the pool edge (i.e. no lip, etc.). The Natural Chemistry representative believe the iron is orginating from the iron oxide used to produce the red color of the pavers, we also have a water feature (waterfall) that originates from the pavers and most likely runs over some on it's way into the pool.

So here is the question, the latest treatment recommended was "Stain-Free" + "Metal-Free" + "Scale-Free" , backwash (24-48 hours) followed by a weekly maintenance of "Scale Free". But before I try this treatment I wanted to know if you guys think this will work without attempting to address the pavers (i.e. will the stain be maintainable without addressing the pavers in some nature)?

And if I need to address the pavers the only option ($) I have is to seal/paint the pavers which I don't mind doing I'm just not confident if only painting the exposed surfaces will be enough?

Thoughts?

Thanks in advance,

Philip Johnson

Yeah. I'm quite unhappy with the Natural Chemistry products, since fail to explain that the effect is strictly temporary . . . and sense they utilize a reducing acid (citric acid) known to produce toxic by-products (trihalomethanes) on reaction with chlorine, instead of ascorbic acid (Vitamin C) which does not.

I need to get a update the stains sticky, but let me quickly outline what happens when you remove stains:

1. Metal is introduced to the pool in soluble form, as dissolved iron or dissolved copper, from well water, iron pipes in city water distribution systems, ionizer, corroding heaters, etc.

2. Chlorine + oxygen in the water oxidize the metals into an insoluble form, creating stains.

3. Reducing agents (Vitamin C, citric acid, oxalic acid, 'Iron Out' (sodium hydrosulfite)) are used to RE-dissolve the iron. Almost all of these products are completely incompatible with chlorine.

4. As the reducing agents are destroyed, solubility is lost, and the metals -- which NEVER left the pool -- re-stain the pool.

To actually REMOVE the metals you have to find a way to get the metal OUT of the water. Simply dissolving it temporarily is GREAT for Natural Chemistry and the pool store, but not so good for you.

To avoid recurrence of the problem you must EITHER eliminate the source -- often not possible -- or develop an on-going process that works for YOUR pool, to periodically remove the stains (re-dissolve the metals) AND to continuously remove the metals that are dissolved.

Products like Stain Free can only temporarily dissolve the metal.

Products, based on phosphonates (HEDP) like "The Pink Stuff" can KEEP the metals dissolved for extended periods.

The CuLator product can SLOWLY remove dissolved metals by ion exchange.

I would recommend the following:

1. Get a K2006 kit. No matter what you do, to control metals you'll need accurate testing, which pool stores WILL NOT provide (most can not!). http://pool9.net/tk/

2. Do a metals bucket test on your FILL water and your POOL water. For various reason, metal testing of the water is not necessarily helpful. http://pool9.net/bucket-metals/

Since you suspect that the pavers are the issue, you may want to soak a paver for a week or so, and then perform a bucket test on THAT water. You'll probably need to pour it through a folded old towel to remove any particulants before you run the test.

3. If you fill with utility water, call your water company, and find out if there are iron distribution pipes between you and the water plant, and especially if there are OLD pipe. Old iron pipes can lead to INTERMITTENT release of iron, when nodular corrosion is disturbed. Also, check the interior of your toilet tanks. The porous china will absorb metals from the water, if present. If your tanks are orange or brown on the interior (not: tan or white) your water supply contains iron, at least on occasion.

4. Abandon the Natural Chemistry products as over-priced and under-performing. When you get ready to address the problem, you can get what you need more cheaply from Amazon.

5. If your budget isn't tight, go ahead and purchase some CuLator packs, along with skimmer socks. Put one in each skimmer, and if you like, hang one in front of the returns. Contrary to the maker's info, these do NOT go bad until they are discolored OR contaminated with goo. If you put them UNDER the skimmer socks, you can prevent most of the contamination.

Keep in mind that these work VERY slowly. Putting them in now may not help noticeably, but will gradually reduce iron in the water and may be sufficient to capture new iron entering the pool.

CuLator
Skimmer sock

When you're ready, we can help walk you through the process.

Good luck!

Hi, Philip and welcome to the Pool Forum!

By the way, some of us aren't "gents." ;)