Thx. LL. That's what I was thinking as well. If I'm going to start a new culture from my remaining then i would rather start with all new fresh water. On another note, on my second batch of eggs, I decided to try and move the rock (a little large) over to the fry tank. It didn't work out that well as only 5 hatched and the rest didn't. My first batch I let the fry come out in the parents tank and scooped them up (lot of work). If you move the rock over, do you leave it close to the airstone or position the rock OVER the airstone so as the bubbles are actually flowing right over/into the eggs? I left the rock next to the airstone and I guess it didn't fan the eggs enough. My next batch is due next Wed.