Rena Smart Heater Questions

[fishlove75]

Hello, I purchased the rena smart filter and smart heater. The heater can replace the filter intake and run as a type of in-line heater. So far everything is going great however, I have one question regarding the heater (using as a filter intake). I hope someone here can help. I am using the set-up with a Betta. The flow on the filter is set to low. But the openings on the heater are a little large, and I am concerned about the Betta getting his fins caught. If I were using the regular intake I would just use a pre-filter or something similliar. But as the intake is also the heater, does anyone know if it is safe to use a pre-filter on it. I previously used the fluval edge pre-filter on his old filter intake, and would like to use the same on the new one, but not sure if it is safe on the rena smart heater.

Thanks