View Full Version : Tank drilling/internal overflow box

01/14/2008, 03:57 AM
I have a glass 90cm/45gal saltwater tank that I am setting up and I want to do an internal overflow box in the center at the back. I need 2 holes in the bottom of the tank, is there anywhere on island that does this, or do I have to do this myself or has anyone here attempted successfully to do this before? Also, about the overflow box, is it best to use acrylic or glass? not sure. thanks! CLive

01/15/2008, 04:04 AM
I know Jeff has drilled a few tanks (actually carefully ground a circle out). You need to be sure that your tank isn't tempered glass first. If it's tempered you can't drill it because it will break.

If you have a glass tank it's probably better to just stick with glass IMO. There are a few places on island where you can get the glass cut to your dimensions and silicon it together.

01/16/2008, 01:11 AM
how would I know if my glass is tempered or not? I purchase my tank here in Okinawa if that makes a difference? do you know where exactly I can go to get it cut? thanks

01/16/2008, 07:01 AM
If you bought it here, it is not tempered. Let me guess... Kotobuki? They use regular plate glass. I have drilled glass quite a few times and haven't had a problem yet... everything from 3mil up to 10 mil. I can do it for you if you want. It will cost you some new bits and some beer. so expect to be set back $20 for bits not including the beer... BTW, I like bud light ;) Before you get deep into it, let's talk and discuss.

01/16/2008, 04:43 PM
yes its a Kotobuki 90cm tank. What I plan on doing is have an internal overflow and a closed loop system set up. So I will need to drill a few holes. The back of the tank will require 4 or 8 1" holes along with one 1 1/2" hole for the drain to the sequence pump I have for the closed loop. Inside the tank I will need two holes a 1" and 3/4" hole for the drain and the return. I actually have some diamond drill holes saws that I purchased some time ago from the States. If this is sufficient I would like to start on the tank this weekend. No problem about the beer, thats easy. Let me know what you think and thanks you for replying to my post.

01/17/2008, 02:20 AM
I won't be able to do it this weekend. Wife's grandparents need help and I got called to help... Following is a possibliity... With diomonds hole saws it should be pretty quick. Battery power is our only downside. (i like to be able to vary speed if needed) I recommend you reconsider on the internal overflow and think about external. Maximize your space inside the tank for coral and such. If you get a chance and can swing up to yomitan I can show you a couple projects I am/have done with external overflows.

Now, does this tank have the black bracing on it or is it all glass? If it has the black bracing, it is 5 mil if not, it is 8 mil. With you drilling a lot of holes strength is a real concern... Before we proceed, let's discuss... over a beer or two.

01/17/2008, 04:39 AM
the tank does have the black bracing on it. Whenever you get time let me know and I can go over to Yomitan to look at your projects. thanks

01/17/2008, 05:12 AM
Next week anytime after 4pm is cool. I will shoot you a pm with my #.