Changing from Tap to RO water


New member
I think I might have had copper in my tap water so I changed to RO water (even if i don't have copper in my water i needed to change to RO water.) I did a 30% water change yesterday. Do I need to do something to get the copper out or will it leave with water changes? Do i need to add any additives with RO water? I have 5 fish and no corals but have the lighting for the corals and want to as soon as i clear up whatever is killing my inverts.


Premium Member
Eventually you will dilute the copper to untraceable levels. The trick is to remove all the copper from the water, however by doing a 100% water change you run the risk of stressing your tank inhabitants. So slower is better. I believe that there is a copper detoxifier out there that will render the copper in the water column harmless. But I don't know the success of those products. The best bet is to hold off on inverts until you get this under control.
IMHO if you're worried about copper, get a test kit and know for sure. Guessing isn't going to be reliable. Though you're right, switching to RO water is almost always going to be an improvement.

The RO/DI water itself does NOT inherently need anything to be added to it. However, it can make a convenient vehicle for delivering additives to your tank water, if your tank water needs them.


New member
If you add any corals to your Reef, you need to definetely move away from tap water because of things like Copper or Chorine. Water quality plays a huge roll in the ability to keep corals alive, healthy and growing!


Premium Member
A PolyFilter will turn blue in the presence of copper, and remove it. Hobbyist test kits are okay for measuring copper for medicating fish, but cannot detect levels that are toxic to invertebrates.


New member
Agreed on the polyfilter. It is the quickest way that I know of to remove copper. After you run it for awhile, cut it with scissors and see if it is fully saturated, if not put it back in until it is.