UV Plumbing Question

[Glott3133]

I've read through a few posts on this, but I think I need it spelled out because I want to make sure I do this right.

I just bought a 25 Watt Aqua Ultraviolet UV sterilizer and I want to run it inline with my Vectra L2 pump (with a ball valve to control the flow). If I add the UV to the manifold of the return line, where would I have the line for the water that is exiting the UV? Does it go back into the chamber where my return pump is?

Thanks

 

[DanyL]

Generally, when you use a manifold, or any kind of closed loop it is advisable to return as far as possible from the location the water came in, this comes to prevent it from recirculating the same water as much as possible and in turn optimizing its performance.

 

[Glott3133]

If it's coming from the return line, then returning it back to the skimmer section is probably the most efficient way of doing it? Or is it best to use a separate pump and run the UV?

 

[DanyL]

The very first chamber in the sump, where the water drains from the display would be the most efficient.
Usually this is also where the skimmer is, correct.

A separate pump will not give you any advantage over a manifold besides removing the need to slightly decrease the flow coming back to the display.

 

[Glott3133]

Correct, the first chamber is where the skimmer is. Thank you that is very useful information.

 

[dlsorensen]

Vectra L2 outlet to UV input. UV output to DT return.

 

[DanyL]

Vectra L2 outlet to UV input. UV output to DT return.

For this to work properly, the flow rate of the return pump should match the recommended flow rate of the UV.

It usually means limiting the flow rate of the pump, resulting in a reduction of the total turnover of the system.
This approach isn't necessarily ideal for all systems.

 

[Short Reefer]

This is how i plumbed mine.

 

[dlsorensen]

For this to work properly, the flow rate of the return pump should match the recommended flow rate of the UV.

It usually means limiting the flow rate of the pump, resulting in a reduction of the total turnover of the system.
This approach isn't necessarily ideal for all systems.

True, but as long as the rate you are running is still turning over the DT as you like, then this is the most efficient method as all water returned to the tank has been through the UV vice returning it to the sump and applying a hit or miss sterilization to your water.

 

[DanyL]

True, but as long as the rate you are running is still turning over the DT as you like, then this is the most efficient method as all water returned to the tank has been through the UV vice returning it to the sump and applying a hit or miss sterilization to your water.

That's true, I actually had a similar discussion over this topic on another thread.

The main argument is wether the trade off (if exists) of reducing the total turnover compared to the possibly negligible difference in efficiency worth it in the first place.

Two things that need to be taken into account here are:
1. The greater the turnover is, the more efficient the UV becomes.
2. If you don't intend to run the UV 24/7 in the first place, increasing the amount of time will compensate on the loss of efficiency as well.

 

[dlsorensen]

That's true, I actually had a similar discussion over this topic on another thread.

The main argument is wether the trade off (if exists) of reducing the total turnover compared to the possibly negligible difference in efficiency worth it in the first place.

Two things that need to be taken into account here are:
1. The greater the turnover is, the more efficient the UV becomes.
2. If you don't intend to run the UV 24/7 in the first place, increasing the amount of time will compensate on the loss of efficiency as well.

All true IMO. Reasoning behind why I bought an oversize UV and run turnover at 5x's volume via a DC return pump. Only aiming to reduce algae though and not as a disease deterrent in my case.

 

[YOYOYOReefer]

who says you cant have more than one return pump use the uv output, plus a second pump... or even a 3rd pump
redundency is your friend... same logic with heaters... better to use 3 300 watters than one 1000 watter.

 

[DanyL]

All true IMO. Reasoning behind why I bought an oversize UV and run turnover at 5x's volume via a DC return pump. Only aiming to reduce algae though and not as a disease deterrent in my case.

An oversized UV is certainly an acceptable solution, as long as the target turnover doesn't make it economically and physically infeasible of course.

who says you cant have more than one return pump use the uv output, plus a second pump... or even a 3rd pump
redundency is your friend... same logic with heaters... better to use 3 300 watters than one 1000 watter.

Sorry but I honestly don't understand what it has to do with the discussion above.
Using the UV output to what? to combine 2 pumps together?
if so (and it's a complete guess) than yes, it is technically possible if you have 2 pumps and 2 uv sterilizers.
But it also overcomplicates the whole system and adds an economical burden on what would otherwise be a simple setup. I would much rather go with the route disorensen chose instead, using an oversized UV sterilizer.

 

[YOYOYOReefer]

i dont know what you mean about oversizing.. i have a 120 watt UV and a 80 watt UV on my 300 gallon predator tank

My reef tank is slightly smaller and its got a 120 and a 40 watt on it..

i agree that uv and ozone are both essential IMO.

 

[DanyL]

It's not the wattage that directly limit us here, but the rated flow required to run the UV in line in an optimal setting.
For example, If you want to run a x5 turnover for a system that the recommended UV for it requires a flow rate that equals to a x2 turnover of the system volume, than oversizing it to a model with a higher flow rate would allow you to keep the turnover the same without limiting it to match the requirements of the UV sterilizer.

And my personal views about the necessity of UV and Ozone in a reef tank differs, but it also isn't the discussion we're having here.

 

[Glott3133]

My Vectra L2 is running at about 50%, which is roughly 1500 gph. This flow should be adequate for the 25 watt UV I purchased. I may be able to run it inline with the return pump. Is this a correct assessment?

 

[Glott3133]

If the optimal rate through the UV for a reef aquarium is 1200 gph

 

[Glott3133]

This is how i plumbed mine.

This is what I was thinking. How much flow are you reading through your flow meter?

 

[DanyL]

My Vectra L2 is running at about 50%, which is roughly 1500 gph. This flow should be adequate for the 25 watt UV I purchased. I may be able to run it inline with the return pump. Is this a correct assessment?

If the optimal rate through the UV for a reef aquarium is 1200 gph

If the max flow for the UV in a reef tank is 1,200 gph, then anything above it will make the UV less efficient.
Optimal turnover is a variable derived based upon the total volume of the system combined with the rating of the filtration used.

Anything above it is more of a personal preference, usually mostly influenced by those who attempt to achieve a high, and diverse flow patterns for corals.

 

[Saltyanimals]

good discussion here everyone. I'm with @DanyL on the key is to be able to tune the water flow through the UV according to the manufacture and target objective of parasite or algae solution. Respectively it's not a set GPM number as multiple variables come into play such as your pipe size, bulb size thus contact time required for your objective etc. BRS has a nice comparison on the 2 solutions which is outside of this discussion.

I struggled with my manifold design which also feeds the UV for the same constraints. I can't sufficiently control the flow rate through the UV to my satisfaction and I also went ahead and made sure I return the UV output as a PVC "wye" upstream of the manifold to maximize UV'ed water to DT and not a circulation within the sump.

I see some photos of the apex flow meter like @VNReef1 . How is that working for you? Do you trust it enough when using it to tune flow rate? I've ready they're unreliable thus never went down that route.