Unless you have long arms, 24" deep aquariums are a PITA to work in. Very difficult to reach the bottom in the back of the tank. Plus planted tanks at that depth require strong lighting (expensive) to penetrate to the bottom.
None for a planted discus tank I think they r all too small... at least 180 gallon 6 x 2 x 2 for a planted discus tank planted discus tank r normally hosing big fish so around 8-12 large discus fish 180 gallon is unless u can go even bigger