Got this unit for my herbs - perfect as there is only ~4" of planting depth with trays in place. Complaints: 1) photo online with plants shows 3 tiers, this is 2 (add'l tiers sold separately); 2) came with instructions to assemble unit (attach to railing, etc.), but none on its use. Most self-watering planters have filltubes for water, this has none and so is still a top-watering unit, with resevoirs actually for overflow/reserve. Instructions on the planter's use would have been helpful.