Should I add a sump?

I like to go with 1/3 the tank volume to be sure. Can you fit a 15g tall? That will help ensure you don't have an overflow in the event of a power outage.

 

my space in my stand only fits a 10 gallon. I was thinking of maybe making a seperate stand for a 20 gallon on the side or maybe just build a new stand to house for a bigger sump. The only thing is having to empty some water or whatever I can to be able to lift the tank. Now I am disturbing the tank and stressing out the fish, dont want to do that. So maybe put the sump on the side on a seperate stand? How high should I put it compared to the DT tank height?

 

I've got a 50g capacity sump IN THE STAND of my 125. 10g?

If you go with a sturdy, thick rubbermaid container like I did, you can add a relatively large sump in the stand, 'cuase it will bend thru the door!

Then you get the compartments the way you want, I use smaller plastic tubs in the bigger one, and it works well!

Check it out near the end of my DT video