I'd like to make a suggestion for future grows-
You might want to shell out for the round hydroton. The reason I say this is the SHAPE of the round pebbles vs. the random shapes of the gravel mean that the gravel may actually settle over time and sort of fit itself closer together- like playing Tetris, or shaking a box of corn flakes- and the size of the interstitial spaces will decrease, giving you less root space.
Anyway sorry to hear about the loss; did you at least chop it up for clones to practice your cutting technique?