Ferts are fine but some people have reported problems with excell. I don't know. Co2 if used carefully is fine too.
+1. Same here. Just don't squirting/pouring the full amount straight on baby shrimps and they will be fine. Don't do the 5ml/10gal dose right away, work your way up slowly.Excel is fine too, I only do half dose but they can tolerate full.