29 gallon as Sump Questions

I must be slow since I’ve read a lot about sumps and still have lots of questions. Seems most of the talk is over my head so let me say what I think I know and please correct me.

This is going to be a 90 in a custom stand i’m going to build with the plan to put a 29 underneath, in the stand as the sump.

So what I think I know.

The sump will need biological and mechanical filteration?

The return pump takes water from the sump to the main tank?

Water from the tank to sump is gravity overflow?

I can glue baffles in so the water flows over or through the barriers into the next chamber?

Not sure on this? I can drill the tank (glass) for the return and overflow? Or I need to purchase the tank pre-drilled?

I’ve successfully done many things in this hobby so this is a new area I want to explore plus I love the idea of not having all of the equipment in the main tank.

Please tell me where my thought processes are wrong.

And how to properly drill the glass without cracking it.

 

Mostly correct. However you DO NOT want to drill tempered glass(usually the tank will say on the bottom panel if it is tempered or drillable) for the return you should just be able to have something going over the top and in like a powerhead. To drill glass you need a diamond hole saw(available at your local hardware store) and water constantly on it. And just take your time.

 

Are pre-drilled tanks common?

The ones I looked at aren’t drilled.

You said the overflow goes over the top? What stops water to running over elsewhere?

If you have 2 pumps, they would have to exactly the same output. Even more for the one pumping uphill.

These are the things that confuse me.

 

There's overflow boxes that you can by that hang on the rI'm of the tank and work off of the siphon principal down to the sump. They do save having a tank drilled. Where I'm at there are a lot of large tanks for sale but most have been drilled, I have bought a couple that used a overflow box for saltwater. I use canister filters for my freshwater systems and prefer non-drilled tanks.

 

So non-drilled, you use a canister?

Really want to experiment with the sump.

If most saltwater folks use sumps, they must be effective.

 

Sumps are very effective and add o the total overall volume of your tank. Each type of filtration system has it's pluses and minuses. I'm just getting into the area wher I may consider a fresh water sump system if I go the next step past a 125 gallon tank. That would be a 180 gallon tank.