Hey Guys,

I've got a 100G (Currently: Turtle) Tank that I want to add a sump to, and then eventually turn into a marine tank (when the turtles outgrow it), I was thinking that in the meanwhile I could marine it up, and start to collect the bits I need to marine it up and simply finish up when I migrate the water-dogs out. I was thinking about drilling in an overflow, but it seems that the general murmur at the LFS was that the bottom could be tempered (unconfirmed, so better safe than sorry, right?) and so if possible, I'd not like to find out the hard way.

The suggestion was to drill either the sides, or the back, which doesn't seem like a bad idea. Currently the water is about 3/4 of the way up for the turtles, so I'd like to keep the output around there for the tank's current use, and then the returns either at the same height or higher.

Do you guys have any suggestions? or any considerations I keep in mind?