Thoughts on having 2 flow settings for UV??

[Imback]

Any of you have any experience running 2 flow setting for your UV? I’m thinking of getting an oversized UV and setting it up on its own variable speed pump. Part of the day would be ran at a lower setting (Disease) and the part of the day at a higher speed for (Algae & Bacteria). This would allow a lot of flexibility in the parameters. Example, 6 hrs at low speed and 18 hrs the higher speed.

 

[Reefer5640]

I’ve had this same thought myself. Interested to see what others say

 

[vanpire]

I don't understand what benefit it would bring you. At slow speed, your UV would kill both bacteria as well as clarify the water, and it doesn't have to be that slow if it is an over-sized unit.

I can only guess you are thinking algae grows so fast that you need to run more water the clarify the water. Algae grows only during daylight hours. Bacteria can theoretically multiple in either daylight and darkness....so what happens during the time of day when you are running your pump too fast for your UV to kill bacteria?

Anyway, I run my UV at low water volume to control any bacteria, and it clarifies the water just fine.

 

[Reefer5640]

BRS has done a few videos on uv and saying you need to decide what you intend to get out of your uv; bacterial (slower flow rate) or water clarity (faster flow rate). If slower takes care of both I wonder why they wouldn’t just suggest that to everyone. I don’t know tons about uv and it’s possible I misunderstood their video...

 

[ca1ore]

This seems like overthinking to me! If you buy an 'oversized' unit, you're going to be able to get enough of your tank water through at even the slower sterilization (parasites mainly) rate to also handle clarification (algae and bacteria). If you don't buy an 'oversized' unit, then you probably aren't going to get adequate sterilization anyhow so might as well run it at the higher clarificaiton rates.

 

[theMeat]

Interesting
Would think running it at lower setting would do everything

 

[Feet4Fish]

I would recommend getting with it reason the biggest h it you can afford and have space for and running it on the parasite flow rate. This would accomplish both goals. The difference of flow rates for parasite versus algae does not hinge on the flow rate itself but more specifically the tank turnover through the skimmer. Bigger, longer skimmer will have greater contact time with greater volume of water.

 

[Miller535]

I agree with running it slow.

I believe BRS claims in their video that slow flow removes parasites and fast flow removes bacteria and algae. They claim the algae and bacteria reproduce so quickly that unless a substantial amount of the tank volume makes contact with the uv every hour it will not have "the desired effect" on bacteria and algae.

Again, I do NOT agree with them.

 

[joey123]

I've looked into this. What you want to do, in order to accomplish both, is one of two things.

A. Get 2 units, sized appropriately, and run one fast and one slow.

B. Get one unit, way oversized. Run it at protozoa speed and it will do both. Here's how you find the right size.

Basically, the protozoa killing is a function of slow speed through an adequately sized unit to get the exposure time. Note: ANY unit you get, run slow enough, will get the exposure time to kill the protozoa. The algae is killed at this exposure time too. Thing is, it is also killed at a much faster flow rate, because it needs less exposure time. The algae control effects are a function of how often your whole tank volume gets sent through the unit. So, we want high enough flow to control algae, AND long enough exposure time.

Here is a no fail way to size one unit for both effects:

Figure out what size unit you need for your tank, and what flow rate you need, sized for algae control. You want the higher end of the faster flow rate. Now, take a larger unit that is rated for protozoa control with the low end of the range at that fast flow rate you figured out before. You will run the unit at the low range of this bigger unit, which is a flow rate that aligns with the higher speed on your smaller unit.

This way, you are getting the tank turnover required for algae control, AND the appropriate exposure time to kill protozoa--remember, this larger unit is rated for protozoa at the rate you are running it at.

Please let me know if I can help explain further. I think that should hopefully be clear enough though!

 

[Miller535]

BRS i feel has done everyone a disservice by claiming this "fast/slow" uv deal as fact. When it's their anecdotal experience at best.

 

[Reefer5640]

I've looked into this. What you want to do, in order to accomplish both, is one of two things.

A. Get 2 units, sized appropriately, and run one fast and one slow.

B. Get one unit, way oversized. Run it at protozoa speed and it will do both. Here's how you find the right size.

Basically, the protozoa killing is a function of slow speed through an adequately sized unit to get the exposure time. Note: ANY unit you get, run slow enough, will get the exposure time to kill the protozoa. The algae is killed at this exposure time too. Thing is, it is also killed at a much faster flow rate, because it needs less exposure time. The algae control effects are a function of how often your whole tank volume gets sent through the unit. So, we want high enough flow to control algae, AND long enough exposure time.

Here is a no fail way to size one unit for both effects:

Figure out what size unit you need for your tank, and what flow rate you need, sized for algae control. You want the higher end of the faster flow rate. Now, take a larger unit that is rated for protozoa control with the low end of the range at that fast flow rate you figured out before. You will run the unit at the low range of this bigger unit, which is a flow rate that aligns with the higher speed on your smaller unit.

This way, you are getting the tank turnover required for algae control, AND the appropriate exposure time to kill protozoa--remember, this larger unit is rated for protozoa at the rate you are running it at.

Please let me know if I can help explain further. I think that should hopefully be clear enough though!

Makes sense.

 

[Reefer5640]

So if I were to run one of the two options, the oversized unit makes most sense to me since it would be the cheaper way to go. I do have one concern, maybe you guys can straighten me out. Since a UV sterilizer can’t distinguish good bacteria from bad would either scenario suggested do too much damage possibly? Or is it not enough to be a concern?

 

[ca1ore]

BRS i feel has done everyone a disservice by claiming this "fast/slow" uv deal as fact. When it's their anecdotal experience at best.

Never have actually watched it. I have CIS (chronic impatience syndrome) which causes me to politely mutter ‘get to the point please’ over and over again.

 

[ca1ore]

So if I were to run one of the two options, the oversized unit makes most sense to me since it would be the cheaper way to go. I do have one concern, maybe you guys can straighten me out. Since a UV sterilizer can’t distinguish good bacteria from bad would either scenario suggested do too much damage possibly? Or is it not enough to be a concern?

UV cannot distinguish between useful and not useful bacteria, that’s true; but since the former is on the surfaces of your rock and sand, it’s unaffected.

 

[piranhaman00]

Beneficial bacteria do not live in the water column. They are there, sure, but not in any relevant numbers. I use two 40 watt Pentairs on a 230 gallon system. The idea was to run one for clarity and one for parasites. However, that fell through when I hard plumbed them to the return and realized that I didnt want that high of turnover. So they are both used for parasite control now, 200-400gph. The water has that UV clarity still though so its working well enough.

The reason you want fast flow is to turn the tank over many times per hour, this will keep it crystal clear.

 

[Reefer5640]

Thanks

 

[Imback]

I've looked into this. What you want to do, in order to accomplish both, is one of two things.

A. Get 2 units, sized appropriately, and run one fast and one slow.

B. Get one unit, way oversized. Run it at protozoa speed and it will do both. Here's how you find the right size.

Basically, the protozoa killing is a function of slow speed through an adequately sized unit to get the exposure time. Note: ANY unit you get, run slow enough, will get the exposure time to kill the protozoa. The algae is killed at this exposure time too. Thing is, it is also killed at a much faster flow rate, because it needs less exposure time. The algae control effects are a function of how often your whole tank volume gets sent through the unit. So, we want high enough flow to control algae, AND long enough exposure time.

Here is a no fail way to size one unit for both effects:

Figure out what size unit you need for your tank, and what flow rate you need, sized for algae control. You want the higher end of the faster flow rate. Now, take a larger unit that is rated for protozoa control with the low end of the range at that fast flow rate you figured out before. You will run the unit at the low range of this bigger unit, which is a flow rate that aligns with the higher speed on your smaller unit.

This way, you are getting the tank turnover required for algae control, AND the appropriate exposure time to kill protozoa--remember, this larger unit is rated for protozoa at the rate you are running it at.

Please let me know if I can help explain further. I think that should hopefully be clear enough though!

thank you. That was a great explanation and that’s what I’ll do.

 

[Patx]

Hi,
Ok so, let's pull out a pratical exemple
(Like in my case)
I think it will help clarify some of us...
and me, tank you ;Shamefullyembarrased

45 gallons tank, return 200ish gph.
15w aqua advantage 2000+ spec:
Salt Water Sterilizer to 75 gals / Flowrate – 233 gph for 90,000 µw/cm2

If the uv is instal inline on the return.
Its should be enough to includes all the types and at the good rate ?

 

[Reefer5640]

So in defense of BRS their most recent video actually does talk about both of these scenarios as options. Just watched it.

What Does a UV Sterilizer Do? Is It Worth it?

Find out what you can accomplish with the proper use of a UV sterilizer.

www.bulkreefsupply.com

 

[Imback]

So this is what I decided to do to try and kill both algae/bacteria and Protozoa. To keep things simple I’m going to just refer to the gallons in my DT.

My DT is 150 gallons. I went with the 80 watt unit. For Protozoa this unit will require 450-600 flow.

Water Flow Rate
Protozoa
180,000 µWs/cm²
Suggested/Maximum
450 GPH/600 GPH

If I run at the suggested flow, this will cover Protozoa.

As for the algae/bacteria. It requires less exposure to the UV (30,000 µWs/cm²) so the current flow at 180,000more than covers that but it needs to turn the tank over at least 3 times in an hr to cover the quick life cycle of algae/bacteria. Being that the tank is only 150 gal, then I’ve covered that as well.

Now, run the speed at 500 GPH and I’ve covered the refugium as well.

Thoughts?

Thank you joey123