Sorry for being a noob

[cassd]

I want to add a sump to my tank I have a hole drilled at the bottom of my tank only and I really never seen a sump do e but I have tried to read some of the posts here and just don't understand what people are talking about so I want to know is if my idea is correct or not so I want to know
if I put a PVC pipe with an elbo going to my desired tank height going to my sump and then a pump in the sump with a return hose how powerful of a pump do I need? It's a 90g tank and have a 67g tank I want to use as sump if it will fit I'm not sure of diameter of pipe because its plugged sine I got the tank and I never removed ill be moving in a month and will open it when I drain the tank for the final install of everything.
so I know nothing about sumps and need to know if this setup is ok and what I need to take note of when setting it up

 

[cassd]

T

 

[ascarbo27]

post pics so everyone can see what your talking about.

 

[cassd]

I didn't buy anything yet because I don't know exactly what I need and won't know diameter of hole in tank till I drain in

 

[striferitus]

Is the tank with the hole a reptile tank because if the bottom pane of glass isn't tempered you could have a bad day when I gets filled with water and shatters

 

[paulW]

Is the tank with the hole a reptile tank because if the bottom pane of glass isn't tempered you could have a bad day when I gets filled with water and shatters

If it's a reptile tank, then yes, don't fill with water. I agree with that.
I have 8 glass tanks that don't have a tempered bottom, that are drilled for bulkheads. It works fine. Other people have much more.
It's ok to have a hole in a non-tempered FISH TANK.

OP, it seems like the easiest thing for you to do is:
Put a bulk head in the hole.
Put a piece of PVC inside the tank , attached to bulkhead. This will be your overflow. I'd recommend putting a strainer designed for PVC on top to prevent fish and other stuff from falling in. (see jehmco.com).
Connect the "outside" of the bulkhead to your sump. It will drain down.

You need to size your pump to your drain. It's actually better to be too small on the pump than too large. If the pump is too large, you will end up having to put a ball valve on the pump output to restrict flow. Obviously, you can't return the water to the tank faster than it will drain.

Want a rough rule of thumb? This is not scientific, but I think the drain should be roughly double the diameter of the tubing coming from the sump.
So on my tank, I have two pumps in the sump, they are rated for 3/4" pipe. Then I have two drains that are 1.5"

The other thing is: The sump must be large enough to handle a power failure. if you turn off the pumps, a bunch of water will drain into the sump. Make sure you don't overflow it.

That should be the basics...