newbie piping questions - what size return - what size overflow?

[Milad]

yes its a peninsula
its going to be used as a "wall" between living room and office
i believe the hole are 1.5in i think.

[golf nut]

Stick with the first plan aq-rear-1.jpg unless you are prepared to drill more holes, if the holes are drilled for 1 1/2 bulkheads and you use a nominal return pump then the Herbie drain will be more than adequate, if they are only 1 1/2 holes in the glass then I would get it drilled properly in which case you have a clean slate to do as you wish.

[Milad]

is 1.5 a weird diameter? im not 100% sure what they are im going by what i remember when i saw the tank. I wont have it until 1.5 weeks from now. They could have been 2"

I just want to make sure there is a backup for the backup. I would die if 180g of water went everywhere!

bloodasp suggestion doesnt look to bad i just dont know if its going to pull in the same water it returned or not.

i could just plug the existing holes and drill 3 new holes...

this is hard setting it up as a peninsula, very little to work with.

[golf nut]

Peninsulas have their share of problems but principles stay the same, get the hole sizes then we know what you have to play with.