copper and brass

[saltysteven]

I know we all have copper pipes and i pretty sure brass is another form of copper- some of us have brass fittings as well.
I just want to clear something up; well Id like you guys to clear something up:

-Copper and brass before R/O is okay.

-Copper and Brass coming in contact with any saltwater is very BAD!

[Thunk]

The way I understand it you simply never want to introduce any metal into to your fishtank system. So weather its water conditioners, or RO/DI something has to make sure the metals are out of the water before it goes in the tank. Metals leach into water pretty readily.

[Sk8r]

YOu've got it right: you can input into your ro/di with copper pipe: freshwater doesn't erode metals the way seawater does. But ro/di and seawater must not come in contact with brass, copper, even stainless steel. The reason? Ro/di water is 'empty' water and tries to 'fill' its empty spaces: it's not too aggressive about dissolving metals, but I still wouldn't do it; but saltwater [you know your salt mix contains many, many minerals besides sodium chloride [salt]] ---saltwater is downright corrosive to metals. Look at the Titanic, which is covered in rustsicles and falling apart.

Plain water coming into the ro/di filter is uncleaned and already contains just about anything you could name. It's 'stuffed' water---but 'stuffed' with mostly non-corrosive things, and consequently doesn't have near as much corrosive tendency, because all its little gaps are already filled with nitrates and phosphates and metals and phenols and arsenic and the like that the ro/di is about to take out... Ro/di, being 'empty' is able to take in the salt mix very fast, after which the water becomes like a buzz saw for metal surfaces.

[DrBDC]

:thumbsup:

[Savas]

Sk8r provides an excellent summary of the chemical principles of "water." This is my understanding as well.

To demonstrate this, soak a piece of copper in ro/di water for a minute and then taste it - spit it out. It will taste metallic with only a short time in contact with the metal. Water in your pipes is typically in contact with your pipes for 4 hours (I read this when they were building my house).