Double Sump Setup?

First off. I'm terrible at describing things but I'm gonna try to be very detailed and hopefully it'll make sense... Moving along... So. I'm planning my 420gal filtration system. I was thinking I'd have 2 75gal tanks for sump system . First. Sump 1 will have sponges and ceramic rings for chunks(turtles are tenants). Then sump 2 will have carbon, ammonia remover, fine sponge, matrix, and heater... So I've got that part decided. My dilemma is: I'm not sure how to properly and effectively connect the 2 sumps/tanks. One of the tanks happens to have a hole drilled in the side already, so i was thinking i could put a pipe in the hole. Raise up sump 1 and let gravity move the water from sump 1 into sump 2. So there's my plan... My questions: Will this work? Should the sump flow-rate b a trickle? Will the pump empty sump 2, faster than sump 1 could fill it up? Hopefully my questions make sense. Thank you for any suggestions u can offer, links to videos, whatever

I'll post a pic once i get home of the drilled tank... One of the 75gal is set up for sump already. Has the sock and such. But i was worried that one 75gal sump and one fx5 won't b enough "chunk" filtration for the planned population: 2 turtles, lrgmouth bass, channel cat, pumpkinseed sunfish and central stoneroller. Assumed i would need more... So. Figured adding an extra sump just for chunks would b a good idea.