there seem to be a few quirks with humboldtii.................the large clone i have seems to prefer a different soil mix than the other type.........also it likes room to run......it grows fast if given room.......ive got a huge mass of stollens sub surface....FAAAAAR more than the amont of leaves would indicate......reniformis is similar in that reguard but more so....most ppl have a humboldtii that seems to be the bromeliad dwelling type. the large clone that i got a hold of last year seems to be a terrestrial type that loves heavier soil and doesnt mind getting a tad dry between waterings......