Ask me! Ask me! Haha. I have heaps of experience with chunkified SS GH+!!! LOL Mine has been a solid chunk/block at about 40% full. Initially I used a hard metal spoon to scrap bits of it off (also aquascaping scissors, tweezers, anything I could find that is hard enough really). Towards the last 10-20%, I decided it was too hard so I poured in some rainwater (this is what I usually use... you could use RO I guess) and dissolve whatever remains in there and have since been using the 'liquidfied' form to no ill effects. I have done this for over 4 months now. I have TBs in the tank. As for substrate, my only experience is Cal Aqua BEP. Shrimps/fish were added in a week running off a matured canister filter. Np issue. Sorry I do not experience with ADA, Fluval or Benibachi so can't comment. Good luck!