Hey bro, your cubes need to be resting on the water channels,not level with the top plate which only serves to act as a light block to prevent algae growth from light penetration in the root system, let your block touch the channel,if your blocks are the same as grodan in the uk ,they should have straight channels cut in them,leave the wrapper around the sides and place so the channel are going with the flow of water to avoid water logging. I have a gt100 too, 4 plant max for a nice thick root mat. I hope that helped. Ooops! I just saw the date, sorry. At least you now know for future reference,good luck, good growing,4:20 ;-)