Friday, December 6, 2013

Preventing Corrosion with a Calcite Cartridge Filter


I have a well system, with extremely hard water and clear-water iron. I have installed a water softener system followed by a large rust remover system the same size. I also have a large RO system with a booster pump installed which feeds the pot filler faucet, refrigerator icemaker, and sink faucet. My new plumber just discovered that the original plumber hooked it up to copper pipe through the walls and floor from the downstairs RO to the upstairs users. My new plumber says he needs to tear into the walls and floor and ceiling and replace the lines with PEX. It's odd that copper would have been used on the RO line, since the rest of the house I know for sure is plumbed with PEX. 

Anyway, rather than tearing into the walls, how about if I add some sort of inline filter after the RO tank that would put back some form of minerals to take away the corrosion potential? We have no current problems with minerals or rust (very soft and clean water), I am just worried about blowing out a copper line since we are gone most of the time from this vacation house. 


Buck L.


Yes, you can continue to use the copper line to your refrigerator from your RO system without any problems, by installing a calcite filter cartridge on the line before the copper starts.  The tubing leading to the calcite filter should be regular poly RO tubing, but after the calcite filter it can be copper.

Preventing corrosion is critical to maintaining a safe water supply.  Copper corrosion can not only cause pinhole leaks, metallic odors, and blue staining of fixtures and appliances, but adverse health effects as well, including gastrointestinal issues and liver or kidney damage. 
Cutaway of a corroded copper pipe
The trick with water like yours is to find the right concentration of calcium.  Pure water, "the universal solvent," will dissolve metal pipes over time without a suitable mineral buffer, but will cause scale buildup and pipe/fixture damage if its mineral concentration is too high.  The goal, then, is to have neutral water that won't form scale deposits nor corrode your pipe. To determine your water's scale and corrosivity potential, use the Langelier index: if your water's Langelier number is positive, it is oversaturated with calcium and will likely form scale deposits; if it is negative, it is undersaturated and will corrode your pipes; you want your water to fall squarely on 0 in this index, as this indicates that your water has just the right calcium concentration and won't damage your pipes or plumbing.

2.5" x 10" Calcite Cartridge Filter
For an application like yours, we recommend a 2.5" x 10" calcite cartridge filter.   Such a filter will fit standard 10" housings, and can be easily installed on your existing line.  It will adjust your water's pH and prevent pipe corrosion by adding just a bit of calcium to your water.  The taste of your water shouldn't be affected much, though some people have reported that they prefer the taste of their water after a small amount of calcium has been added to it.

We hope this answers your question, Buck.  If you should need any further info, don't hesitate to e-mail us at or leave a comment on our Facebook page.
Thanks for the letter!