Sump tank question

[Harleylay]

I recently purchased this tank and it came with a sump...ive never had one before and I see it has bio balls. What is the water level supposed to be?

 

[Harleylay]

Anyone??

 

[salt_for_brains]

Not a big fan of the bioballs but you at least want them submerged if you are using them. You also want the sump level in a range that can hold your main tank drainage during shut down or power outage.