I'm looking for some to put in my aquarium, but all I see are the stupid little blocks you use for your feet. Anyone got any ideas? Can you buy them in aquarium stores? Are they expensive?
Pumice is an inert volcanic rock. Bacterial love it because its porous and water can flow past them. use volcanic rock to achieve the same desired results.
I never had problems getting mine to sink, and I dug through the entire pile at the store to grab all the odd shaped pieces to make it easier/more fun to stack