Skunk: I think that may depend on what type of hydro system you're using. I wouldn't put them into an aeroponics system or you're going to clog your nozzles. I've used them often enough in my DWC's and my DIY Stealth Hydro knock off bubble tubs I built with no problem. The only beef I have with the Jiffy grow plugs, and a couple of others, is that they're dirty; they muddy up the water in an active hydro system. If you encase your pump in a filter bag or a woman's nylon sock you probably won't have a problem, just a dirty reservoir you'll want to clean more often.
You might want to think about that in advance next time. You can start seeds and clones in rock wool and rubber plugs that don't foul up your reservoir when you put them in, but Jiffy's will. But, before you think I'm anti-Jiffy, I'm not. I use them regularly in dirt. They're great there. I hope that helps. HSA