Q1: Bulkhead fittings;
I need 3 bulk head fittings for my tank, 2 large enough for the in/out for the filter (3/4" on a 30gal tank?), and a third 1 1/4 - 1 1/2. I need them as small as possible, can any one recommend a brand or type that i can use, possibly with a link? there isn't much available locally, the ones we do have are of quite large design.

Q2:
Is there a Non glass material that i can use in the modification of the of my Tank that is all glass?
I need a min of 4 - 6 holes drilled into my tank, and at $30per glass hole cut... its not exactly cheap. With out going into too many details, If I can attach some kind of non glass material to the aquarium that will hold a seal in my 30gal tank I can drill the holes my self and save a nice chunk of money.
◘NOTE: It can be just about any material you can think of, non clear is fine.

Lexan would be my material of choice. You can get it at lowe's or home depot and they will cut it to size at no extra charge. plexi-glass will work as well and it is a little cheaper.

Thank you for your reply, I decided to draw up a basic pic of what I am attempting:

How it works is the little box inside the aquarium will house the intake/outtake lines for a canister filter; they come from under the base of the aquarium and go in thur the water tight cube in the center.
The purpose of this mod is so that no wires/tubes/etc will be hanging off any side of the tank, allowing it to become a perfect center piece to be seen from any and all sides with out any unsightly hardware in view.

►So to confirm, for my purpose, If I construct the center cube at the bottom of my tank out of lexan I should be able to attach it to the glass bottom of the tank using silicone and still maintain a water tight seal?
(out of curiosity, why wouldn't plexiglass or acrylic work?)

I would NOT recommend using plexiglass in the scenario you are planning. Acrylic and silicone are not good friends.
Why aren't you drilling your own glass? The bits are reasonably cheap(~$15 per bit) compared to paying $30 per hole. Also, bulkheads are easy to make using PVC fittings from your local hardware store. You just have to make sure that you get the right fittings and remember to use the correct o-rings.
If you do a bit more research on drilling glass and making bulkheads I am sure you can save yourself a heap of cash. All it takes is patience and the willingness to learn.

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75 Gallon Planted

Thank You for the reply, I can differently say I am tempted by drilling my own holes, and would love to learn and such, Its just i dont have faith in my tools for such work at this time, maybe in the future tho.

►So if these plexiglass wont work, will the fist suggestion of lexan work or acrylic?, if not can you suggest something else that might (pvc/cpvc/abs/other?)? Like I said it does not need be transparent.
◘Or perhaps maybe silicone could be substituted with something else that would work?

►thank you for the suggestion on making my own bulkheads, I'll experiment with that.

You might try epoxy instead of silicone, but I am not sure how it would hold to the glass.
As far as drilling goes, I would just buy a sheet of double paned glass and a bit then practice several holes. Drilling glass is not difficult, it just takes patience and care.

Edit: I edited out where I said Lexan and plexiglass/acrylic are the same. Lexan is basically the industrial equivilant to plexiglass.

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75 Gallon Planted