[sick lid]

You'll likely run into problems down the road both with the plants and the under gravel filter as the roots of the plants grow through it. Plants generally prefer to have their root systems undisturbed, but with an UGF, the roots grow below the grate into the water column. Plus, it'll be much harder to move plants if you want. First choice would be a canister. Second choice, a cannister. Third choice, a HOB.