Why would you use a splitter? Just put it on the outtake and you should not use a check valve, really no need for it. You can still shut off the light, the water will still flow threw it!
Except, to get effective full uv sterilization for algae, bacteria and parasites, which is a level 3 sterilization, you need a flow rate of approx 50gph with a 9w bulb. I would not suggest reducing your flow rate from 205gph (what a 206 is rated) to 50gph. And for the uv to just be minimally effective against algae you need a flow rate of 120gph. Decreasing the flow of a pump dramatically can cause issues such as shaft fatigue stress over time.Id put a ball valve on each of the split lines to gain total control of the dwell time. the slower the water passes the uv lamp the more stuff can be killed.
Sorry to bump in, I have dealt with uv sterilization for years.@exv152 just to expand on your response. My fluval 206 is rated max 205gph, but it also has a Flow rate lever for adjustments. I'm not sure what the MIN flow rate for this canister is. Anything lower than 50 gph via the UV will most likely heat the water, right?
So my goal is to stay within the range ( 50 gph- 120gph) passing via the UV.
If I'm looking for effective sterilization to remove free floating bacteria, parasites and algae, should I stay around the lower end range of 50gph or the high end range?
Thx again for all the informative responses