no he came from the plane to my tank basically. i think he was at ebay for a day or 2.
How long have you been keeping marine tanks? from your post count you seem new to the hobby.
let me start by stating that I am not trying to be a jerk, I am trying to help.
With that said being at ebay for a day or two is not coming from a plane to your tank. Contact with any water from any other system introduces the likelihood that the fish will contract whatever disease/parasite that system has.
The collection stations where the fish are held are riddled with disease. Then they are shipped to wholesalers and finally to the LFS where the fish are not quarantined/treated and put into a closed system that IMO is crawling with disease. They are there for a very short time (even more stress) and then brought home where they are usually not treated/given a chance to acclimate to their new captive environment and thrown into a tank with established tank mates that usually don't welcome newcomers. The end result in my experience is a fish that doesn't last long and puts unnecessary stress/disease risk on the established fish.
Once again not coming down on you. Trying to keep you from making costly and frustrating mistakes. We all lose fish from time to time but it is our duty to do the best we can to ensure the survival of these animals when possible. A proper quarantine setup can go a long way to achieving this. I say proper quarantine because the quarantine should have water quality that matches or exceeds the display that they will go into with plenty of hiding places where they can feel safe. Remember we are trying to make sure they are healthy and ready to cope with aggression from established tank mates.
Also when testing pH a properly calibrated probe is the best way to go.
Not really sure why your fish died but I have never seen pH that low in a marine tank and I have been keeping FO tanks for over 20 years (still figuring out the reef thing). If you tested the water after you found the fish dead the decomposition of their bodies may have made it drop.
The quarantine remarks was to try and help you with angelfish as they are not the easiest of fish to keep. I would suggest you give this months TOTM article a read. Copps is a master at the care of angelfish (and marine fish in general) and the article might back up a few of my claims.
Good luck in the future and hopefully next time you will be more sucessful!