Removing metals from water

Ke

0
Sep 29, 2007
106
Toronto
Has anyone tried the Metaltrap Filter? It is supposed to filter out any metal that is in the water. I having been trying hard to keep metal stains away from my fiberglass pool, by adding sequestering agent only keeps the dissolved metals in the water, the Metaltrap Filter is supposed to remove the metals from the water permanently. Any thoughts?
 
I too am learning about this as we are about to set up our first "real pool" .... tomorrow!! If the rain holds off anyway.

Hubby and I are planning on using our well to fill the pool and we know we have hard water... with iron. Our softener recently went out and in 1 day our toilets were brown... yuck! We also filled a small intex kiddie pool this summer I got on clearance the previous summer and it was brown the next morning. We drained and refilled with our softener and it was beautiful the rest of the summer with no work.

I've been reading about various ways to get rid of iron and the metal trap keeps coming up. It would help with initial fill-up, but we would be introducing metals every time we backwash our filter (unless hubby hooks up a softened line just for backwashing)... although a small amount... with our water it may not take much.

We've been looking at various options and thought we'd try a whole house filter.... needed one anyway, and see how it worked. I set up a few white bowls in the kitchen to see what would happen if I set them overnight and added chlorine to them.... one soft water, one hard water, one filtered through the new filter. The softened never turned brown, the hard had tiny bits of sediment in it and started to turn rather quickly even before the chlorine was added, the filtered one was clear initially and slowly turned a faint yellow.

Hubby and I were hoping for better results with the whole house filter, but weren't expecting it. Looks like we will either be using a metaltrap to see how that works, or filling the pool with the filtered water and then adding a chemical to bind the iron together so we can vac it out. Would rather not use the chemical approach, but need to look at cost comparisons to figure it out.

Don't know if that helped at all.... I've read so many places that if you have iron, you have to live with it. I'm learning that that's not true... just takes a little research. I don't want to be adding chemicals to my pool all the time to sequester iron! I'm trying to avoid as many chemicals as I can!!
 
duraleigh said:
To my knowledge, there is no mechanical (filtration) way to remove iron or any other metal from the pool if it is in solution.

Iron in pool water will be in the form of FE3+ this will flocculate itself with any organics in the pool. Metals have a possitive charge and are therefore attracted to negatively charged organics, indeed ferric chloride is used as a flocculent in soft acidic water along with aluminium.

Part of the problem is that sand simply cannot filter out small particles, sand at best can only filter down to 15 microns using some DE in the filter may help. Using zeolites as a filter will work as they have ion exchange properties so will capture the possitively charged metal ions. Zeolites will not work if you have a salt pool though as that stops the ion exchange.
 
Zeolite is known to absorb and remove ammonia from water (not that this matters in a pool since virtually no ammonia will be present when there is chlorine) and I found this link supporting removal of some heavy metals (lead and copper) using SOME forms of zeolite, and I found this link referring to absorption of iron. Zeolite is a type of cationic (positively charged ion) exchange system, but like all such systems they have different selectivity rates and capacities for different types of ions.

As teapot has noted, zeolite doesn't work very well in SWG pools because the higher sodium levels in such pools significantly lower the capacity of the zeolite since sodium competes with other ions for binding to the zeolite. In fact, one "recharges" zeolite by soaking the material in a high salt (brine-like) solution.

I can't comment on how quickly zeolite would remove the iron nor on the capacity requiring recharging of the zeolite nor on which kinds of zeolite would be best for that application. It probably makes more sense to use a known ion exchange resin filter designed to remove iron for the water during a fill and on the fill line for water replacement from evaporation, though during the initial fill there could be a lot of recharging of the water filter required (so having water trucked in for the initial fill might be better).

On a related Zeolite topic, there are some tests being done at NSF International testing Zeolite's claimed ability to reduce monochloramine. I'll report back on those results after the tests are completed. I am skeptical given what I know of the fundamental chemistry, but there's always the possibility of catalytic acceleration of reactions (monochloramine --> ammonia) or direct absorption of a rare monochloramine ion (NH4Cl+) by the Zeolite.

Richard
 
Following on from Richard's post.

There are a large number of zeolites, some naturally occurring and some specifically manufactured. Zeolites with a high manganese content are able to cation exchange and therefore remove iron from solution better than others. As Richard says, it maybe more appropriate to use an ion exchange resin developed for the job (it would still be modelled on a zeolite as that is the best)

Likewise I can't comment on how much a zeolite could remove before needing to be recharged in salt water but never the less interesting to some of us.

Part of the reason I could not use zeolites in my filter is their ability to molecular sieve and cation exchange the copper out of the pool so I am informed which would have been counter to my experiments with copper ionisers.

Just going back to the original topic, the iron in the well water will be anaerobic FE2 that will be changed into FE3 the more powerful ionised version so will combine with organics in an ionised bond so will, if the filter medium is good enough, be filtered out. the iron that causes staining is usually in a different highly oxidised form FE2O3 and usually from corroded metal pipes fixtures etc.

Richard is better at the chemisty than me so I will now shut up!
 

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Well, getting back to OP's practical question, "Will the Metaltrap Filter work?"......it seems no one knows definitively.

My bet it will work just well enough for them to make the claim but probably not nearly well enough to remove iron from an entire pool practically or economically.

Just like a household water softener will work, they simply don't have the capacity to work effectively.

Zeolite appears not to be a practical alternative so shouldn't be in this discussion.
 
I mentioned this on another post recently ... Hubby and I have terrible iron in our water and were trying to decide how best to fill our pool (got a used one and it was very expensive to have water hauled in).

We tested several options on the kitchen counter in white bowls to decide the best way to go. Here are my results after filling and adding some chlorine to the mix.

1. Softened water.. crystal clear
2. Hard water through whole house filter... light brown
3. Hard water through whole house filter and white kitchen towel folded into fourths... very light brown with no sediment
4. Hard water straight from tap... medium brown with some sediment
5. Metaltrap then through whole house filter... dark brown

After all the time spent on testing our water options... Hubby talked to a neighbor who has city water and he let us use his garden hose to fill the pool. :-D If Hubby had only listened to me and talked to him sooner we wouldn't have had the mess of tests to go through :?

Had we not had that option, we would have used softened water or attempted to use the filter and then towels to catch the residual by the skimmer and return. I've read some with smaller pools have had success with that, although it takes an abundance of patience!
 
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