A friend of mine (seriously, he's a friend of mine) recently got some advice that seemed a bit strange to me. He brewed a batch of amber ale and a clerk at a LHBS recommended that if was going rack his beer to his 5 gallon secondary after fermentation had stopped, that he should fill the carboy with water to prevent damage to the beer as it sat in the secondary for a few weeks. I heard this once before and immediately advised against is because that would just dilute the beer. I suppose if the carboy was nearly full anyway then the additional water woudn't dilute too much, but is it really necessary? In all the books I've ready and people I've talked to, I don't remember this being something that I should be doing. I don't even use 5 gallon CB's for secondary, I only have 6.5 gals. I have never had a problem. Any advice on this?