I did some research including online reviews, a search of the forum and stuff posted by JaDeD (or however they type that out.) It seems that the 6gpm flow rate is integral to getting the stated performance, and I can only provide more like ~1gpm or a bit more. At that rate, it appears that instead of 3 minutes to reach groundwater +10F, it will take 15-20 minutes. They recommended against using a pre chiller as it will further restrict the flow. Rather they suggest, if groundwater is not cool enough, stopping at G+10F, hooking up a pump, and finishing by running (not recirculating) ice water. So without 6gpm, it's 15-20 minutes, then break down, reset, and pump for who knows how long.
My IC is 50ft of 3/8in configured in a very loose double coil to maximize contact and flow of stirred wort over the surface area. My pre chiller is 25ft of 1/2in in an ice bath, used only when groundwater temperature requires. My chilling time for 6.5-7 gal wort is never over 18 minutes, with my available ~1gpm flow.
So for now, it looks like I'm better off sticking with what I have. If I could provide the 6gpm, I'd surely try the Hydra, as I know I couldn't push that through my current system. 3 minutes + switching to pumping ice water might still beat my current time.
Hope this info helps anyone else with similar questions to mine.