I usuallly run my 125 gal sump fairly full.

There are 2 outlows, bth about same flow rate, one direct flow. one filtered (below the filtered end)

The pump pushes around 1500 gph on a good day.
Turns out a fish (don´t know which yet) crammed itself into the unfiltered overflow,, got stuck, and backed up that overflow enough to overflow the tank.
Looked like maybe almost 100 gallons spilled oout on the ground before I noticed, sh´te will happen when least expected.
Jammed the fish thru with a screw driver, so that outflow was again free, and started filling the sump again.
Didn´t catch the pic right away in the panic, but as you can see, once together, snapped the pic, with the sump still, quite low compaed to normal.

Got a chance to see the mangrove digging in.

There are 2 outlows, bth about same flow rate, one direct flow. one filtered (below the filtered end)

The pump pushes around 1500 gph on a good day.
Turns out a fish (don´t know which yet) crammed itself into the unfiltered overflow,, got stuck, and backed up that overflow enough to overflow the tank.
Looked like maybe almost 100 gallons spilled oout on the ground before I noticed, sh´te will happen when least expected.
Jammed the fish thru with a screw driver, so that outflow was again free, and started filling the sump again.
Didn´t catch the pic right away in the panic, but as you can see, once together, snapped the pic, with the sump still, quite low compaed to normal.

Got a chance to see the mangrove digging in.