Do not concern yourself with "what happens when I'm not home and my GFCI trips". I used this logic for years as an excuse to not install GFCI, but in the end, I too conceded the logic is faulty. Here is why:
1. A reef tank can survive flatlined for longer than you think. A few hours isn't going to wipe out your reef. Just two months ago, I had turned off one tank to do some maintenance, left the lights on but all underwater devices were shutoff .... got distracted, then ended up doing something else, then went out to run some errands. Three hours later, I remembered that I had neglected to turn my tank back on. My anemone looked a little peeved that the current was gone for so long, but I turned the tank back on and everything was fine in the end. The anemone in question is my 24" ritteri -- one of the hardest anemones to keep in captivity. So don't sweat a few hours. You're not gone from your tank for so long that it can't suffer a little bit until you're back home.
(Of course, I should probably qualify this claim with something like "within reason." A couple of hours is OK but certainly it does depend on what kind of animals you keep, and certainly the longer it goes flatlined the worse it will get, case in point this blackout situation in the east.)
2. Aha, you say, but what about the times I go on vacation for a week or two? Aha, one can say back ... you still have to have someone check on your tank periodically, if for nothing else to feed things, also to check for floods or whatnot or whatever. If you have household or tenants insurance, BTW, you HAVE to have someone check on your place every 24 or 48 hours anyways, otherwise your insurance may be voided in case of a burglary. So ... again, it's not like the reef runs unattended.
3. A GFCI isn't really going to be tripping willy-nilly anyways. If it is, it means something is wrong. Find the problem, and correct it. If everything is fine, the GFCI isn't going to trip anyways.
4. Trust me, submerging your hand into saltwater that is live with 110V hurts. A lot. You will be happy to have something to "stop the pain" in the event you actually cannot pull your hand back. I used to think "oh, well if I feel a shock I'll pull out quick enough." It's amazing how inaccurate that really is. If you just plunge your hand in, to resuce a knowcked over coral or whatnot, how far you can get in the few milliseconds it takes before your brain realizes there is a problem. I've also read horror stories about people being partially paralyzed and unable to pull their arm out.
So I agree with the folks above. You can mourn the loss of your reeftank in the event of an (unlikely) absolute total-worst-case scenario. Or, ... your friends and family could be mourning YOU. And people will be asking how safe it is to have reef tanks in their homes and if children are involved and etc. etc. etc., that is a place we do not want to be going.
That said, it took me FIVE YEARS to get off my duff and put my tanks on GFCI. But don't do as I do, I have to learn everything the hard way. I had to learn by feeling what 110V feels like .... and incidentally, learning what it is like having my WIFE learn what 110V feels like. I thought ... Man alive ... if someone else living with me is at risk because I asked her to do me a favour ... what happens if I have kids? What if a kid is just playing around and innocently puts their hands into something that's live-110V? You know, I guess I can be comfortable enough playing around with risk on myself .... but I cannot live with being responsible for harm done to another.
I'm sorry if I sound like I'm using scare tactics. Ultimately it is your tank and YOU should be the one to decide what risk you're comfortable with. Lots of people don't run GFCI. But lots of people do, and the reasoning for it is reasonably sound in my view.
cheers
PS. Oh and BTW, WELCOME to CANREEF!!!
