I have a 20g long and a 29 gallon that are going on the same stand, one on top of the other. I want to set them up as one system where the bottom works like a sump and have them both filtered with a canister filter with the input and output being in the 29g . The 29g will be a community tank and the 20g will have african clawed frogs so it will need lower flow than the 29. Anyone who can help please do not sure if that is even possible but please share your advice. Thanks in advanced.