TexanCanuck
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- Feb 10, 2021
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Sorry for jumping in here so late ... but there's another dimension that it is important to consider here that I haven't yet seen discussed so I thought I'd play Monday-morning quarterback ...
As you know, for a UV unit to be effective, it needs to have flow through it at a particular rate. If the flow is too low, you won't get enough "turnover" through the unit and therefore it will not be effective at overcoming undesired parasites or algae (because they will proliferate at a rate higher than what you can sterilize). Conversely, having flow rate that is too high will mean that the water won't "dwell" inside the unit long enough to achieve any sterilization at all. To further complicate matters, the amount of "dwell time" needed for sterilization depends on the specific organism you are trying to treat for: parasites require more dwell time than algae (for example).
Therefore, if you really want to get the benefits from your expensive investment in a UV sterilizer, you need work backwards through the plumbing problem:
1) Decide what organism you are really trying to deal with in your UV ... algae OR parasites. It is very difficult to do BOTH in the same unit, unless you dramatically oversize the lamp
2) Based on your treatment objective, use the manufacturer's recommendation to determine what the flow rate THROUGH THE UNIT needs to be
3) Then figure out the plumbing to achieve this flow rate. Remember - the advertised discharge flow rate for a given pump will NOT be the actual flow rate you get through your plumbing!
I just wanted to point this out so you don't make the same mistake I did ... spend a ton of $$ for a treatment solution and NOT get the result I was looking for.
Based on the discussion in this thread so far, here would be my observations:
1) wherever possible, plumb the UV through a dedicated pump with the plumbing as short as possible and with as little vertical height between the pump and the discharge of that loop ... this will allow you to select a pump that is closest to the flow rate you actually need to achieve your UV goals
2) the ideal solution is two return pumps and two UV sterilizers, with each pump set to deliver the flow rate required for one function (i.e. algae vs. parasites). For an example of one, see pictures of my setup at the bottom of this post ... I use variable speed pumps and flow meters to tune the flow rate through each UV sterilizer
3) If you can't use separate return pumps, your next best option is creating a "closed loop" ... and a closed loop in the sump works just as well as in the main display tank. The flow rate through the UV is going to be much smaller than the slow rate between the sump and your display ... so while there will be some small amount of "recycling" through the UV, the vast majority of the water processed through the UV will get returned to the main display. Just size your UV and closed loop pump slightly larger than what you'd need for your display tank alone (perhaps assume 20% larger)
4) if you can't create a closed loop for your UV (i.e. a dedicated pump for the UV that returns back to the same body of water that the pump draws from), then you can connect the UV to a throttling valve off of your main return line to the display ... but remember that the probability of you getting the "right" flow rate through the unit is very small. In this case, you really do need to invest in a flow meter, or spend the extra time to measure the flow manually (using a bucket test) when you set it up for the first time.
Here's what my setup looks like:
As you know, for a UV unit to be effective, it needs to have flow through it at a particular rate. If the flow is too low, you won't get enough "turnover" through the unit and therefore it will not be effective at overcoming undesired parasites or algae (because they will proliferate at a rate higher than what you can sterilize). Conversely, having flow rate that is too high will mean that the water won't "dwell" inside the unit long enough to achieve any sterilization at all. To further complicate matters, the amount of "dwell time" needed for sterilization depends on the specific organism you are trying to treat for: parasites require more dwell time than algae (for example).
Therefore, if you really want to get the benefits from your expensive investment in a UV sterilizer, you need work backwards through the plumbing problem:
1) Decide what organism you are really trying to deal with in your UV ... algae OR parasites. It is very difficult to do BOTH in the same unit, unless you dramatically oversize the lamp
2) Based on your treatment objective, use the manufacturer's recommendation to determine what the flow rate THROUGH THE UNIT needs to be
3) Then figure out the plumbing to achieve this flow rate. Remember - the advertised discharge flow rate for a given pump will NOT be the actual flow rate you get through your plumbing!
I just wanted to point this out so you don't make the same mistake I did ... spend a ton of $$ for a treatment solution and NOT get the result I was looking for.
Based on the discussion in this thread so far, here would be my observations:
1) wherever possible, plumb the UV through a dedicated pump with the plumbing as short as possible and with as little vertical height between the pump and the discharge of that loop ... this will allow you to select a pump that is closest to the flow rate you actually need to achieve your UV goals
2) the ideal solution is two return pumps and two UV sterilizers, with each pump set to deliver the flow rate required for one function (i.e. algae vs. parasites). For an example of one, see pictures of my setup at the bottom of this post ... I use variable speed pumps and flow meters to tune the flow rate through each UV sterilizer
3) If you can't use separate return pumps, your next best option is creating a "closed loop" ... and a closed loop in the sump works just as well as in the main display tank. The flow rate through the UV is going to be much smaller than the slow rate between the sump and your display ... so while there will be some small amount of "recycling" through the UV, the vast majority of the water processed through the UV will get returned to the main display. Just size your UV and closed loop pump slightly larger than what you'd need for your display tank alone (perhaps assume 20% larger)
4) if you can't create a closed loop for your UV (i.e. a dedicated pump for the UV that returns back to the same body of water that the pump draws from), then you can connect the UV to a throttling valve off of your main return line to the display ... but remember that the probability of you getting the "right" flow rate through the unit is very small. In this case, you really do need to invest in a flow meter, or spend the extra time to measure the flow manually (using a bucket test) when you set it up for the first time.
Here's what my setup looks like:
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