Permanent Tank Dividers - A Few Q's For Your A's

[Chris's Fishes]

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!

[seabass]

I believe that most of the commercial systems use dividers similar to this:

 

You can add powerheads to each section to supplement flow.  In addition. I believe that they have an overflow on one end, and the return on the other (so that the water flows through each section.

 

Holes, slots, or bulkheads with strainers can all be used.  Routers, drills, saw blades, and even lasers are commonly used to cut acrylic.  Depending on how professional you want it to look, you might even have someone cut the panels for you.

 

Yeah, silicone doesn't adhere to acrylic like it does glass.  This might be more of a problem when using acrylic baffles in a glass tank sump (as the pressure difference can be constant).  However, the silicone will stick to the glass fairly well, so the dividers will probably hold well enough with a good bead of silicone on each side.

[Chris's Fishes]

I had planned on having the panels cut and shipped to me - but adding cuts (or holes) would have raised the price from $50 per sheet to $200 per sheet. Seems a bit much, to me!

 

It seems as if I may not have to have as many holes as I thought. Maybe one hole every 3" across and 6" down? I just don't want to take out too much material and have a super flimsy piece of acrylic left.

[jonny roks]

Is laser an option? Try and see if you can design and have a local place laser cut. They normally charge by the hour.