I'd heard the Coralife sterilizers use proprietary bulbs. I've had inlines before and hated the fact that the bulbs came out the bottom. This and build quality was why I bought a Pentair. You can get aftermarket bulbs, but I just get mine from J&L
I use a 15w on my 110g system, but if you want some overkill, go with the 25w. There's not much beneficial bacteria floating around in the water column, so it won't do any harm that I can find proof of
If you only want to control green water, the 15w will do just fine
Pentair maintenance is easy compared to inlines I've owned
My pump is after the skimmer and socks so the water is as particle-free as possible
As far as pumps go, I can't help as you'll have to calculate your head loss. I use 3/4" vinyl hose and an Eheim compact 2000 to pump through my sterilizer and then my chiller. I get about 225gph after both, so it's perfect for me as I am getting 15wpg/hr
There's some good reading
here if you need more info on flow rates/effectiveness
Specifically, this section;
*As a Clarifier; For Algae Control (Green Water and some Cloudy Water), 40-50 gph per watt is effective to maintain effective exposure for effective UVC sterilization/radiation (depending on model UV’s design).
High Efficiency (High Dwell/Exposure) UV Sterilizers such as the
TMC Pond Advantage with long contact time as per the wattage and lamp can easily run as high as 50-60 gph per watt. The even higher efficiency (& dwell time)
Pro Clear UV 30 can go 70+ gph per watt.
*As a Sterilizer; Generally for bacterial control (& many virus) a flow rate of 20-25 gph per watt (75-95 liters per hour, per watt), sometimes as high as 30-35 gph per watt for high efficiency UV Sterilizers such as the
TMC Vecton UV.
*As a Sterilizer; For single cell parasite control (such as Cryptocaryon) as well as a few “stubborn” viruses, a flow under 10 gph (or even less) is necessary. This is often not 100% for all parasites of this type, so a UV Sterilizer should not be relied on as the sole preventative for these parasites!