yesterday I emptied my 35g cichlid tank (kept my 5 cichlids in a 10 gallon for the hour or so as I was preparing it). I then emptied out the old substrate (which was a mix of sand and flourite) and cleaned out the tank then added my white sand and calcuim carbonate (white) rocks (which were prewashed). Then added the fish back in and I'm back in business (did a great job of stepping on and cracking my glass top, luckily I had strong tape to fix it). I had to add baking soda cause my ph was down to 6.6 alkalinity was very low also. Hopefully those rocks will help get the ph up and I hope I get home and my fish are alive! Stressful for those little guys, took me forever to get them out of the tank, they dodge that net like pros! the water cleared up a little bit but once it clears up completely, I'll grab some pics.