when buying a filter How many times would you be wanting the water to circulate per hour (ie a 200 litre per hour filter would circulate a 100 litre tanks twice a hour) This is taking into mind that the filter is filled with standard media and is internal. I need to know as I have to decide on a filter tonight and need to know what I looking for. This is for a 110 ltre tank and I have to decide between a stingray 15- 200 litre per hour, a fluval something - unknown litre per hour but expensive and a Hailea BT1000- 1000 litre per hour. I really need some help ,someone please give me some advice