UV x 2? Mounted on side?

[Desert Darthead]

Purchased a used 200 gallon glass aquarium and trying to plan out the entire system while the stand is being refinished. One area I am struggling with is UV. I am leaning towards 2 separate UV systems: 1 at lower flow for protozoa and 1 at much higher flow for algae and bacteria. This will be a mixed reef, but likely lots of fish. Due to size, I am looking at Aqua UV 57 Watt systems for both. The low flow would be plumbed inline with one of two return pumps (Reef Octopus VarioS-6) and the other would have a dedicated pump (Reef Octopus VarioS-8) to ensure proper flow rates.

My questions:
1. Anyone else use 2 UV systems and if only 1, are you going low flow or high flow?

2. I know the manufacturer recommends they be mounted vertically (not an option in order to mount in stand and be able to change bulbs), or horizontally with valves pointing up to prevent air. This is a challenge to have flow sensors and ball valves if mounted in stand above sump. Anyone have experience mounting them with valves to one side at 90 deg? This would allow mounting on underside of stand with much more room for plumbing.

Appreciate comments. Hoping to start a build thread soon once I have a few more details figured out. Thanks.

 

[billwill]

The valves need to be at a point to not allow air to get trapped. That’s why they go up in horizontal install. You could likely get away with rotating as close to vertical as possible. I wouldn’t geek out too far on the flow rates, but then again I’m a keep it simple stupid kind of guy. Figure out the flow with a bucket one time and move on.

 

[45bravo]

Similarly I'd run them as close to vertical as you can. However as long as the output and input are facing upwards, if they are angled then have the output higher the bubbles should still just travel along the inside of the body and go out as normal. It would almost make you think why would you have them perfectly vertical because you'll have a pocket at the top of the UV body if the initial flow was not enough to flush the air back to the output. Someone else might have a better understanding of the being perfectly vertical part, but that's what makes since to me.

When I used to manage a saltwater aquarium store we had one mounted horizontal on the wall, I think it had 7 bulbs in it, and the input and output were just facing up, we never had any issues.

Remember not to feed them off the return if possible or you'll be wasting some time feeding some of the same water you just processed again.