I'm shopping for new power filters for a 40 gal & a 100 gal I want to set up. Ive had fish years ago & I am just getting back into it. Does anyone have an opinion on the Tetratec PF300 & PF500 filters? I like the heater feature, but I've had an Emperor 400 on my 60 gal before w/great results. How do they compare? Any suggestions would be helpful.