Can you seal aluminum coping to prevent potential corrosion with SWG?

missmarcelot

Gold Supporter
Feb 11, 2020
12
Pittsburgh, PA
Pool Size
30000
Surface
Vinyl
Chlorine
Salt Water Generator
Hello, I would really like to convert to SWG, but we have aluminum coping. Is there any sort of sealant that could be applied to the coping to prevent the pitting/corrosion that I see occurred in other threads here? Are there any other reliable prevention methods?

Thanks!
Marcy
 
Hey Marcy, Is the coping doing anything now.. Most people do not know that a chlorine pool is a salt water pool... I bet you have over 1500 ppm salt right now and a salt pool is about 2500 to 3500 salt..

Can you get pictures of your coping now? As far as coatings I have no idea...
 
Hey Marcy, Is the coping doing anything now.. Most people do not know that a chlorine pool is a salt water pool... I bet you have over 1500 ppm salt right now and a salt pool is about 2500 to 3500 salt..

Can you get pictures of your coping now? As far as coatings I have no idea...
Thanks for responding. The coping is brand new - it was installed this summer. It's grey colored, powder-coated aluminum bullnose coping. my only pic is cropped from another photo from the construction phase - not sure it helps you much but I will attach.

After searching the forums here I have learned that there is concern for aluminum specifically with SWG and there are a few threads regarding pitting on aluminum coping with SWG pools. I'm hoping to find a way to make it work with both somehow.
 

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There are low salt SWCG units. Mostly sold in Canada. Investigate if one can be purchased here in the states. They cost more for less generation.
That sounded like a really promising idea, but our pool is 33k gallons and it looks like based on your link the specifications are only for pools up to 25k gallons. Maybe there are others? I'll keep looking!
 
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Powder coating, which you already have, is one of the best surface protections you can get for metal and ali surfaces. You could add a two pack clear varnish but these tend to yellow with time and you may already have some form of clear top coat.

I looked at a low salt SWCG variant, they were 2-3X the cost of a standard SWG. As mentioned both bleach and acid add salt to the water. I’m now just on a month after startup and we’ve gone from ~120ppm salt to ~750ppm from bleach and acid additions.

While aluminium would not be my choice of material for pool coping you have to work with what you have. At ~4000ppm the salt level for a SWG pool is around 10% that of a marine environment at 35,000ppm and now where near as harsh. Having said that powder coated aluminium is very common for pool fencing and gates etc. and your coping should give you years of service, just be cautious of both acid and bleach around the pool.
 
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Powder coating, which you already have, is one of the best surface protections you can get for metal and ali surfaces. You could add a two pack clear varnish but these tend to yellow with time and you may already have some form of clear top coat.

I looked at a low salt SWCG variant, they were 2-3X the cost of a standard SWG. As mentioned both bleach and acid add salt to the water. I’m now just on a month after startup and we’ve gone from ~120ppm salt to ~750ppm from bleach and acid additions.

While aluminium would not be my choice of material for pool coping you have to work with what you have. At ~4000ppm the salt level for a SWG pool is around 10% that of a marine environment at 35,000ppm and now where near as harsh. Having said that powder coated aluminium is very common for pool fencing and gates etc. and your coping should give you years of service, just be cautious of both acid and bleach around the pool.
Thanks Steve. Yes, in hindsight, I wish I could go back and possibly make some different decisions there, but it is what it is now. I came across this item, I am wondering if just a little of this rubbed on the coping may help (especially as you point out the salt ppm is really not very high) or if I'm forcing a square peg in a round hole here.
 
No, I wouldn’t use that. That appears to be primarily for unfinished metal or aluminium surfaces. You have a painted surface however they do say in the Q&A section that it wont damage painted surfaces. They advise against using where a slip hazard may be an issue - not for floors. I cant tell if its oil based or silicon maybe but I would be worried about it washing into your pool.

This is a generalisation for marine coatings but they tend to be formulated to be flexible rather than durable
 
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Spray bed liner will protect it for a VERY VERY long time, basically it is rubber coating... I have had 2 weights in my salt water pool for 6 years covered in bed liner and there is 0 rust on them.... They have some nice looking ones now.. :) I have no idea about this company, just did a web search...



Just found this video, the black would look awesome on your coping :)


 
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That sounded like a really promising idea, but our pool is 33k gallons and it looks like based on your link the specifications are only for pools up to 25k gallons. Maybe there are others? I'll keep looking!

Anybody ever added 2 SWCG's to a pool? Instead of having one SWCG after the filters and heaters but before the valve splits to the returns, do the valve splits and then put two SWCG's on to of the returns. Would have to ensure the valves stay open to the SWCG's though....

Or, if you had 2" piping coming out of the filters and heaters, use a tee to split into two 1.5" lines. Put a SWCG in each 1.5" line. Then tee them back together before the return valves.

Andrew
 
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