How many holes?

[bch044]

If I decide to drill my 125 how many holes do I need? what size? location?

How do I tell if my tank is tempered? All the glass has a slight green tint to it, if that matters.

Where, size and how do I build a internal overlow?

I am also planning on running a closed loop with 4 discharges and probably 2 intakes.

Sorry for all the questions, but as you can tell I know very little about this.

Thanks as usual,
Steve

[EdKruzel]

Much of it decides what you wish to do with the tank. You can place an overflow in the tank covering the entire top to bottom length, the entire back or side, or you can use a minimal overflow with only a 90 degree elbow and a strainer.

The green is from the iron in the glass and is quite common, should it be tempered it should (but not always) have a sticker on it stating so.
The most basic setup for what you've described will require 7 holes.

That is one overflow, 2 discharge points for the closed loop and 4 returns with a "U" tube used to return water from the sump. If you look up the size bulkheads you wish to use, it will tell you how large the hole must be cut in order to properly seat it.

[bch044]

anyone else

[Shagsbeard]

Get a pro to drill it for you if you are at all hesitant to drill it yourself. They usually charge on the order of $20 a hole.

Edit: Buy your plumbing before you drill the holes. Have that ready so you can tell how large of a hole you need for each bulkhead.