Glad to hear that you seem to be ok however keep a close eye on everything because most test kits that are available to us don't provide readings low enough to detect copper in small amounts and it does not take very much to be toxic for inverts and coral

YOu have a good point and the only way to be 100% sure is to put a cup of carbon runing in loop wit a small filter to make sure the water is really going through it, in a bucket with like a gallon or half a gallon of water for a day, then analyse that water. in my own test it reached .358 ppm which is 3 times the dosage to kill ich. with this test you can be 100% sur that if there is copper in the carbon the common test is going to tedect it easily.

If that come out negative, it was not copper in the carbon. If it does contain copper in large quantité like mine, then you have the culprit right there and a sample should be sent by mail to the company.

I do agree. However the fact that I am reading 0 on multiple tests and I still have all my coral and inverts doing perfectly fine I think I will be ok. I am still going to be removing the fitting of course I'm just not going to have to cry myself to sleep thinking about a full tank overhaul.
It was just a standard seachem test kit but I do not have the resources to bring my water to a lab.

Edit. The seachem test kit actually test to 0.01mg/l. And seawater is .003 so yes I could have some undetected but I cannot test to the quantities that could be present.

Sorry to hear about the crash and cause! Thanks though for posting and making us all aware of the potential disaster!
I just did a search for ANY copper fittings anywhere near yhe R/O in use.