Permanent Tank Divider - A Few Q's, For Your A's

I've got the idea in my head that I want to divide a couple tanks with sheets of black acrylic. I plan to keep a pair of clownfish in each division, and would like for the tank to work as one system (so, both sides would share water), instead of completely dividing the tanks live I've seen some people do. I'll be doing this on two tanks - a 29 and a 55. Questions:

1) I've heard it's easy to drill acrylic - is this correct? I'd probably do 1/8" holes every 3" in a grid on the acrlic sheet to allow plenty of water to pass through. It doesn't have to be a high-flow transfer, but I don't want significant parameter differences between the two sides. Are there certain bits that might allow me to less the chance of cracking the acrylic, or is that chance pretty negligible? This stuff isn't going to be cheap, so I'd rather not have to re-order. I do own a miter saw, so I guess I could do slits instead of drilling if that's safer, but I think I'd prefer holes.

2) How thick should I go? I was thinking 1/4", but I could go 1/2" if I absolutely needed to. I'd like for it to be strong enough to hold back all the water on one side, just long enough for the water level to equalize between the sides. Some bowing is expected with acrylic, I know, but I'd rather it not bulge insanely far during a water change or something.

3) What's the correct silicone to use for this? I was thinking about using this plastic silicone mix: GE 10 oz. Silicone Cartridge-GE-55 - The Home Depot
Through personal experience, I've found that GE #1 tends to let go of acrylic pretty quick, so I'm hoping that something formulated for plastics might be better. Thoughts?

Any other advice is appreciated!

 

I was wondering at first about using plexi-glass, but i know that can crack real easy from cutting/drilling etc. Haven't really done any hands-on with acryllics.

 

I was wondering at first about using plexi-glass, but i know that can crack real easy from cutting/drilling etc. Haven't really done any hands-on with acryllics.

Isn't Plexiglass just a brand of acrylic? I thought they were pretty much one-in-the-same - there are different strengths, but same material. Or am I wrong?

 

I have used acrylic for other projects and it can be drilled safely. I used painters tape on both sides and placed it flat onto plywood for the drilling. I also used a brand new bit to make sure it was not dull. I didn't add many holes so I don't know how many you can add before you lose integrity. I don't know about the acrylic but as long as you make sure it is aquarium safe you should be OK.

 

Isn't Plexiglass just a brand of acrylic? I thought they were pretty much one-in-the-same - there are different strengths, but same material. Or am I wrong?

I was kind of wondering that myself as well. They do seem very similar. As far as bits go, i would say make sure they are sharp and drill as straight as you can. Like mimicking a drill-press. That should go a long ways to preventing cracking,, especially in the summer. Can get brittle in the cold. I would also probably get more than you think you need, because just in case!