Drilling Quesions

[chief799]

I am considering drilling my 29g tank, and was wondering how large the holes should be. Also, how far below the top of the overflow should it be drilled?

[bnumair]

hole size is dependent on what type and size of bulkhead you are going to use. placement of the hole depends on if overflow box will be used or just a bulkhead with strainer.

[chief799]

Than you for you response. I'm not sure how big of a bulkhead I need to get the proper flow rate, do you have any suggestions? Also, is it better to have the overflow box or just a strainer?

[billdogg]

IMHO, a bulkhead smaller than 1" is a waste of time. I prefer to use an overflow box. If you go to www.glass-holes.com they can set you up with matching bulkhead/hole saw combinations to fit the bill
hth

[cnreef]

I just recently drilled my 29g and used the glass-holes 700 gph kit with the 3/4 locline return kit.

[Jchris896]

I'll second the gl*******s kit. Worked like a charm.

[apstreck]

I drilled 3 holes in my 75 gallon using glass holes bulkhead and drill bit. Only thing I didn't like was I feel like the drill bit lost its cutting power pretty quickly. Granted, I was nervous about it and went very slow, but it took 15 minutes to drill the first hole, 30 to drill the second hole, and almost an hour of drilling to drill the third hole. I had a buddy help me and had cool water running on the bit the whole time, and stopped every 3-4 minutes to flush the site and rinse the bit. Next time, I'll spend a bit more money on a name-brand drill bit.

I would definitely recommend making an internal overflow box if you are going to drill. That way, if your pump stops due to power outage, it won't drain until it gets below the strainer... depending on how far down your bulkhead is, that could be a LOT of water. I had a box that was 5 inches tall and 4 inches out from the back of the aquarium. The top of the box goes about 1/4" above the where the rim starts, and my holes were 3-3/4" to center below the top of the glass (measured from inside the aquarium).

I am a newbie too, so take my 0.02 however you like, but I have to respectfully disagree with not going smaller than 1" for a bulkhead, especially on a tank that small. I run a 3/4" beananimal drain, and with a 800 gph return pump (not including head loss so ~500-600gph), I had to scale back my siphon by over 50% with the gate valve. If you are concerned about snails or whatnot making it into the pipe and clogging it, just put a strainer on the intakes inside the box. Plus, even if your pipe can handle some big snail coming down the drain, its gonna get stuck at the gate valve regardless. Here is a reference for pipe size vs flow rate: http://flexpvc.com/WaterFlowBasedOnPipeSize.shtml.

Not trying to say any one way is right or wrong, I just don't understand why people are so inclined to go so much bigger with their plumbing than is required by their return pump.