Your cube and ritteri are ok though right?

That really sucks... Sorry to hear about your Angels...

What kind og GFCI are you using? Could it be they are just a crummy brand/model?

I would replace your GFCI if you think they tripped for no reason, GFCI can also trip on an overload so you could have been drawing just over 15A and it is taking along time to heat up to a trip condition.

I feel your pain, sorry to hear about that. I personally just had my 28g tank crash when a 9 year old kid dumped all my fish food into the tank, 4 hours before I came home.

Sorry for your losses, that really sucks.

Tony, what do you all have plugged into that GFI circuit?

Yikes man. Too many losses for you in one week Tony!

Seems like lots of us are suffering losses ATM. I lost my true perc today,, but I have myself to blame for that in the end.

Anyways, sorry for the losses :(

Most of the times I've had a GFCI trip, I've been able to find the cause. This is just one of the few for which I'm not able to find a cause. I've had about 4 or 5 like this in as many years. I'll go with current overload as a likely culprit as because it happened just after the lights turned on. The only thing is that it should not be anywhere near the 15A limit.

Moreso my lesson learned though here is that I would prefer an alarm of some sort for the future. Indeed - the GFCI tripping tells us "something" but that is not the real root of the problem - the problem is that "stuff happens", and when it happens when you're in a position where you can only assume that things are OK - then it would be nice to be notified somehow.

Cube tank with the ritteri and its inhabitants appear to be OK today. Other than now being a fishless tank, the 20g appears OK too. Snails, abalone, etc. - everything but the fish - weathered the flatline just fine.

Doesn't compare to a total tank loss but I'm just sad today anyhow..

The ballast for your lights will draw a large startup current about 10X normal for a few seconds as the bulbs strike an arc and charge the coils and caps. if you are already running higher than normal this quick draw can be enough to trip the breaker,
its like when i run my chopsaw it draws 14A when running but 28 when it first starts up and trips the breaker if its already been heated at all.

I realize there's a surge but I'm not sure what the peak draw is during the surge. The lights on this particular circuit are one 250W DE and then 4x24W t5's over the 20. Not knowing the surge values, my general strategy has been just to generally try not to overload the breaker, ie., try to keep it no more than half, ie., 7 or 8 amps. I should reassess all the items on it, but at least at time of writing this, I don't think I'm overloading the circuit. If it is a dodgy GFCI, I'll be retiring the hardware soon enough anyhow though, restringing wires, etc., so hopefully it will be a moot point in time.