Aegle, it definitely works for you, those are beautiful specimen..you did good! The 'anti-sand speech' was just in case you ever run into problems in the future.

My friend's looked like yours too until somehow the humidity in the room got up higher.. Sand can be a breeding ground for bacteria if its stale. Most people think cactus needs sand. So did my friend. Same with Pedros...

If they ever turn funky use a lil fungicide like 'Actinovate', works wonders..