Thank you for your answer, I broke an ohko stone to make scattered stones This is the work in progress : 1. I had several problems with the scape : the significant difference in height ... that was horrible, I built my own substrate supports because TGM was not answering for days. Ada gravel (front) mixed with ada malaya because I made several tests, failed etc.. Finally I needed more height with front substrate (8 cm), because RH corner is almost 20 cm. I decided to use sand instead of ada gravel (see 2.), but ada gravel was interesting because of his weight (first step is more stable). Two layers (gravel and sand) is not esthetic for front view, but finally it's a good choice for stability (it is a good support for malaya slopes). I don't know if my explanations are understandable. -> I can make a frame to hide the two layers (front). 2. According to me, ada la plata sand was too light, except for the sand path on the left, so I would like some gradient color between ada plata sand and ada mekong sand (sand path : front - dark -> back - light). I'm working on the gradient color. 3. I think path's height (back of the tank) is a little too low. But It's too difficult to add another substrate support (too much visible). Finally, I would like to not move anything, it's not perfect but I'm ok with it. Is it possible to grow HC on ohko stones (with glue ... ?) I'm going to upload a video.