How much sand will I need for a 125? Also has anyone on here used sandblasting sand? Its $3.50 for 50 pounds. I know a guy thats been using it in his fresh water tanks for years, and it looks good. By changing to sand from bare will this change my water quality, any spikes? I have always had sand bottoms and when I moved 4 months ago I changed to bare bottom and from a 72 to a 125. I think I like the sand better, any help would be great. Thanks Mike