Hello and welcome :
Most all filters are rated for fish gallons (this for 100 fish gallons) not turtle gallons ! SunSun says 370 gph , you must understand that most all rate there filters without media. Also any finer pads if used will slow flow down even more ! SunSun do have some decent products , if you plan to use this filter for 30 gallons water or less for a turtle it could do an ok job but sure you will have higher maintenance with it. Small amount of media but does offer mechanical ,biological and chemical filtration. It's 50/50 what I hear about this filter. Be careful intake and discharge piping is very flimsy and difficult to get syphon to work ... yes give's a 9watt sterilizer one of the smallest. Will work some for bacteria and algae but not parasites. That wattage with that flow is a mismatch , For a 9watt needs to have a slower flow to work better to kill algae , around 120gph.
http://www.drsfostersmith.com/pic/artic ... icleid=435Bottom-line as a beginner it's a fair filter you could do much worst. Again will only handle 30 or less turtle gallons ! Turtles are very messy !
These are my thought's about it.