Question about bulkheads and pvc fittings

  • We are currently upgrading MFK. thanks! -neo
anarekist

anarekist

Jack Dempsey
MFK Member
Apr 4, 2011
2,177
9
38
Los Angeles
ok so im trying to figure out what kind of bulkheads do i need to set up my new tank. the overflows have two holes at the bottom of the tank.

one 3/4"
and one 1"

i want to use schedual 40 pvc pipe for a durso stand pipe and the return. what kind of bulkheads do i need to get? i see pictures of them and they all looked threaded, do i have to buy an adapter that has a slip and threaded ends to connect the pvc pipes? are there ones that are all slip? really need some clarification here :(
 
ok new question, the bulkheads i got i think are the wrong size. the holes at the bottom of the overflow/weir seem to be exactly 3/4" and 1". i got bulkheads for those sizes but it seems the outer diameter of the bulkhead is too big. does this make sense for a 220 gallon? since it seems that i need a 1/2" bulkhead and a 3/4" bulkheads respectively for these holes, will those pipe sizes be enough for the flow i would need in a 220 gallon? also i would like the use the size bulkheads i already have, whats a good easy way to increase the hole size in acrylic?
 
The holes in the weir of your tank are WAY too small!!!!! Yes the hole in the tank for the bulkhead is much bigger than the pipe the bulkhead connects to. I would not go any smaller than a 1" drain pipe (about a 1.5" hole for the bulkhead)... and really strongly consider a 1.25" drain pipe.

A 3/4" drain pipe is going to severely limit the size sump pump you will be able to run. A 1/2" return pipe is also way too small! For a 220g I would want a 1.25" drain and a 1" return... actually this is what I plan to drill my 110g glass tank for, 1.25" drain and 1" return.

Is it an Acyrlic tank or glass? Drilling a plexi tank... no problem. Drilling a glass tank... not that hard but a little nerve racking... UNLESS the glass is tempered then don't drill it!
 
thank you for your reply, the problem is that these holes came with the tank, i have no idea what the previous owner was thinking, maybe more of reeftank with lots of tank side circulation. how do i enlarge these holes since i dont wana cut new ones, and most hole saws require a pilot hole to start, should i just get a dremel and just slowly enlarge the hole? btw it's acrylic.
 
Acyrlic makes the job doable.

Yes, most hole saws come with a pilot bit in the center. If you could somehow use a drill press you could use a hole saw without a pilot successfully. I have a hard time envisioning getting a 220g on a drill press though.

Are the holes in the side or the bottom? Either way the easiest way to proceed might be to secure a piece of wood behind the existing holes. The wood would hold the pilot bit while the hole saw starts the round groove that will become the hole.

Here is an idea to get you started in coming up with a solution. Cut a piece of 1/2", 3/4" etc of plywood the size of the inside bottom of your tank. Put the plywood in the bottom of the tank. Clamp a piece of 2x4 at each corner to temporarily secure the plywood in the bottom. Turn the tank over and drill.

Or maybe this might work. Put a fair sized piece of plywood on the dirt. Put the 220 tank on top of the plywood. Drill from the inside bottom of the tank through the bottom.

It is possible to use a hole saw by hand without the pilot at all if you have a very steady hand and can brace your arms/elbows on the substrate to be drilled. You don't start perfectly perpendicular to the substrate but at a slight angle. Once you have developed a little smile shaped groove you can slowly tilt back to perpendicular. I have done this many times but NEVER on a tank or with acrylic... usually on a 2 x 4 that needed a hole enlarged and the 2 x 4 would usually later be covered with drywall so small slips didn't matter. I am not recommending enlarging your holes like this just giving you food for thought..... EDIT: Oh Yeah... this works better with a slightly dull hole saw than a brand new sharp one as slightly dull doesn't catch like a brand new sharp one does.
 
Another approach is to use the hole saw to drill the size hole you need in a piece of 1/4" plywood. Then you can clamp (Double sided tape?) the 1/4" plywood to the outside bottom of the tank positioning the hole in the plywood where you need the hole in the tank to go. You can then use the hole in the 1/4" plywood to guide the hole saw without a pilot bit.

This might be the easiest way to go?
 
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