Once I read that both are good, but it depends on your local water supply. If its hard it was better to use one product than the other. Not sure were I read it thou.
Eheim Pimp Club Member #86
50G Tank; Eheim 2026 Filter, Eheim 2213 Filter, Hydor ETH 300w heater, 9w UV Steriliser, CO2 Pressurized system with JBL PH Controller & Aqua Medic 1000 Reactor, 3wpg lighting, Tetra Plant substrate
60G Tank; Project 1500l Filter, 2 Hydor 150w heaters, 9w UV Steriliser, JBL CO2 Pressurized system with Eheim diffuser, 2wpg lighting, Tetra Plant substrate