Waterbear: Something interesting I found on metal stains.

[Guest]

This one seems to contradict the belief that high calcium is helpful.
He's saying that the lower the calcium hardness is, the less work the sequestrant has to do on the calcium, thus making it more effective preventing stains.

I would still have to go along with your advice since my calcium hardness is VERY LOW already, and I've been having such a battle with stains. I am going to continue increasing my CH until it's around 300.

What are your thoughts on this article?

Also, am I reading this right. The sequestrants are usually in liquid form and actually may do some good as far as removing the stains as well as preventing them?

Chelators vs. Sequestrants

 

[JasonLion]

This is all consistent with what we say here.

On fiberglass in particular, medium CH levels (around 220-250) can help prevent stains from forming in the first place. This is unrelated to what happens with sequestrant and CH. High CH levels can require you to use more sequestrant.

Sequestrant alone is usually enough to remove stains that are new, but stains that have been around for a while usually require ascorbic acid, or something similar, to remove them.

 

[Guest]

This appears to be a bit of a catch-22. You would think his article would mention the benefits of higher CH levels in the first place. Otherwise pool owners like me, would conclude that their low CH is desirable for stain problems while using Sequestrants.

Everything is in moderation, I suppose.
It may be that the right thing to do would have been to remove all stains in the first place while CH is still low, use the sequestrant, then slowly raise the CH levels to reduce the dependency on the Sequestrant?

In the last year, the sequestrants just didn't do much good in preventing the stains from coming back, and this is while the CH has been so low. So, for me, getting the CH back up is a no brainer because I have nothing else to lose.

I'm going to get my water in perfect balance and forget about the stains for a while. When they bother me enough, I'll re-do the entire vitamin-c treatment.

This is all consistent with what we say here.

On fiberglass in particular, medium CH levels (around 220-250) can help prevent stains from forming in the first place. This is unrelated to what happens with sequestrant and CH. High CH levels can require you to use more sequestrant.

Sequestrant alone is usually enough to remove stains that are new, but stains that have been around for a while usually require ascorbic acid, or something similar, to remove them.

 

[Guest]

The effects of calcium on fiberglass gelcoats have NOTHING to do with the use of sequesterants. Apples and oranges! Cobalt spotting (leaching from the gelcoat) is directly an effect of low calcium in much the same way that plaster damage is to a plaster pool. The effects of higher CH levels helping prevent staining has been documents but the actual mechanism by which it does so is something that I am not familiar with. I have seen much emperical evidence that it works, however.

Here is some useful info on sequesterants and chelators (which for our purposes are really the same)
http://www.poolforum.com/pf2/showthread ... questerant
(the whole thread is useful but read my posts in it for an explanation)

 

[Guest]

T
It may be that the right thing to do would have been to remove all stains in the first place while CH is still low, use the sequestrant, then slowly raise the CH levels to reduce the dependency on the Sequestrant?

Not gonna happen! Once you have metal in your water or stains in your pool all you can do is get rid of the stain by redissolving the metal back into the water (which is what ascorbic acid does) and then create contidions that are not as conducive to the metals restaining (weekly to monthly sequesterant dosing, proper water balance, keeping close tabs on pH and running it on the low side of normal, shocking by adding bleach into the skimmer with the pump running so any stains form on the filter media instead of back in the pool--and are possibly removed by either changing or acid washing the filter media)

In the last year, the sequestrants just didn't do much good in preventing the stains from coming back, and this is while the CH has been so low. So, for me, getting the CH back up is a no brainer because I have nothing else to lose.

Get your water balance in line! The seqesterant can't do it by itself if the pH spikes or you don't put sequesterant in often enough or if you water is too soft.

 

[Guest]

You know what I think I'm going to do?
Get my water balanced and keep it that way for a few weeks before I do another stain treatment.
It's really never been right since I had the pool because the previous owner and pool companies drove the CYA up so high and damaged the heat exchanger by putting the pucks directly in the skimmer. For that reason, I'm afraid to put any chlorine at all directly in the skimmer, even though it is safer than the pucks.

I will continue to pour it over a return jet and brush off the sides and mix it in well. I will continue using the sequestrant.It almost appears as though the sequestrant is loosening up some of the stained areas. There is some dirt and residue and they seem to be gettng slightly cleaner when I brush those areas after vacuuming.

Thanks for all the education and advice. I'll keep you updated. I'll send some pictures soon, just in case your curious.