flow in sump

[BlueTang<3]

so i have a question how much flow are you running in your sump i got a 75 gallon sump about half full of water got a couple koralia 1 in there as that is what i had lying around seem to be a bit smelly the odd time could be the skimmer or filter sock just wonder if the stagnant water could also be an issue i guess i should mention 250 total water volume 2200 gph return pump