I recently picked up a Fluval flex from my LFS and added hardscape two days ago. Yesterday I filled up the Flex and added plants. It has pearlweed, Bacopa, Rotala, A tiger lotus, and crypts. Today I transferred over some established filter media (enough that it should be able to support a decent bioload right away) and added in 3 male guppies. Really liking it so far. Once the plants establish I’ll be trying to get a pearlweed carpet.