This is the exact set-up I have - just worried it won't be enough. It's a 250g display tank. I'd feel a lot better if the battery backup I ordered got here because it should be able to run my return pump(s) for a couple of days.If you run one mp40 with 2 batteries daisy chained together, I would expect maybe a few days of flow. If it were my tank, I would have the mp40’s going along with a bait bubbler and hope for the best. Good luck to you.