i do the fork for some tanks. and for one of my tanks i have a smallish piece of lava rock, i tied fishing line to the rock and tied that to my light fixture(with enough length to reach the bottom of the tank). when i am not using it, it hangs out of sight behind the tank, still attached to the light fixture (clear fishing line is almost invisible). I use rubber bands to tie veg to the lava rock. cheap and easy