Folks, if you've recently upgraded or renewed your annual club membership but it's still not active, please reach out to the BOD or a moderator. The PayPal system has a slight bug which it doesn't allow it to activate the account on it's own.
If I'm not mistaken, I think Ken (chazotte) has 2 of those on the tank in his basement. Hopefully he will chime in and give you his opinion.
I've did some research on those when I was looking for lighting for my 30 cube. I read of a few of them falling into the tank, that was enough for me to start searching other options.