To UV or not UV

Do you use a Uv sterilizer/clarifier in your system

  • Yes

  • No

  • Yes when needed


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Freenow54

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Awesome, thank you! Do you recall which pump you used that fit back there? I'm assuming DC so you can control the flow rate but it has to be strong enough to make that whole entire loop.
You don't have to use a DC pump. You can plumb it with fittings adding valves to have a bypass so you can work on the light itself , a line controlled by a valve to run at the proper flow rate for parasite control , and a separate line for algae that is what I intend to do. I already have the fittings but not the light itself. I researched it all I know the pipe sizes and flow reduction due to friction ect. My line is 29 inches up , and 4 over and about 10 to 15 down . All I need is a 150 gph ac Danner pump. That also gives a good tank turnover
 

Freenow54

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I honestly have two. One for low flow and one for high flow so I get the best of both worlds. Either don’t do it at all or do it right. I don’t want disease or algae. That being said my tanks only 48 gallon so my two units cost less than most of the single larger units.
I will take that bet look on Amazon for Geek UV lights cheap to begin with and replacement parts readily available and cheap as well. I am buying one $ 250 that will perform both purposes , have to buy a pump for $ 150 and plumbing . I priced others and especially the quartz sleeves are almost as much as a new unit, Some don't even offer parts. My Geek I use on my RODI is so cheap if it comes down to it its not even worth fixing just buy new. I would like it if you would share your equipment information I love to be proven wrong
 

Australian_Reef

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It will work for your intended purpose if you have the right UV dosage (wattage/flowrate) ti your tank size. Sicce should give a guide to the flowrate to steralise alage for your tank size. A sterilisation dose for ich/crypto would be a lot higher.
 

Freenow54

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If you read through the posts I explain proper flow rate and also how to make sure you have the proper light and what te difference is between stated wattage and effective wattage you need a UV-c bulb
 

t5Nitro

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Didn’t know so many people run them intermittently. Mine has run continuously for years. Should I change to running it 12 hours a day and prolong the bulb use?
 

NanoSteam

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Didn’t know so many people run them intermittently. Mine has run continuously for years. Should I change to running it 12 hours a day and prolong the bulb use?

It's up to you, there are benefits to running them partially, it's believed it kills off good things in the water column as well. If you do decide to do this I think the best way is to run them opposite of light schedule so it works on things that go into the water column at night such as certain Dino strains. That's going to be what I'm planning on doing for my setup. Save on electricity and bulb life.
 

mcarroll

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Correct. It’s highly unlikely hundreds if not thousands of hatched eggs will pass through the uv without at least one finding a host and restarting the cycle
Of course one will get through – one is not the problem. Immune systems handle one without even noticing.

The operative part of control is that the number of swarmers not be allowed to reach the level where their attacks can crater your fishes immune system. In an uncontrolled situation, there is almost no maximum number reached, their popuation just continues ballooning. But before you get to control....

It's the fishes response to the ongoing assault that is the problem...not only can its immune system eventually run out of fuel, but the constant stress can casuse the fish to shut down its own immune system "for survival". Supposed to be so it can divert all resources into escaping the situation – which is a great strategy in the wild. Doesn't work in a glass box. (Doesn't work in a stick-built house either. ;) )

So strong UV+micron filtration along with a real stress management plan for your livestock is what most people mess up with "management".

To most people, it seems like "management" just means watching your fish eat. They don't have awareness of stress, or the danger of meds. They seem to want "QT" to be a magical thing that cures "whatever my fish has" even if the fish doesn't have anything.

Makes me wonder why Sicce would advertise 80-250g on a 13w and how it has so many positive reviews. As for flow rate a pump is included with the clarifier
It's advertised as a clarifier – which implies algae control. Most UV is just used to control "green water", so they are sized appropriately.

If you want to use one of these types of units for parasite control, check out the recommendations for UV units on my dino thread.

All that said, I wonder if you really need a UV unit at all? You didn't mention anything about fish or algae or anything else as to why you wanted it.....just that it was on sale. Without a reason for using it, you can't really know what size to get or how to best install it. IMO consider taking a pass and get one when you need it. 👍
 
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MikeReefs

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Of course one will get through – one is not the problem. Immune systems handle one without even noticing.

The operative part of control is that the number of swarmers not be allowed to reach the level where their attacks can crater your fishes immune system. In an uncontrolled situation, there is almost no maximum number reached, their popuation just continues ballooning. But before you get to control....

It's the fishes response to the ongoing assault that is the problem...not only can its immune system eventually run out of fuel, but the constant stress can casuse the fish to shut down its own immune system "for survival". Supposed to be so it can divert all resources into escaping the situation – which is a great strategy in the wild. Doesn't work in a glass box. (Doesn't work in a stick-built house either. ;) )

So strong UV+micron filtration along with a real stress management plan for your livestock is what most people mess up with "management".

To most people, it seems like "management" just means watching your fish eat. They don't have awareness of stress, or the danger of meds. They seem to want "QT" to be a magical thing that cures "whatever my fish has" even if the fish doesn't have anything.


It's advertised as a clarifier – which implies algae control. Most UV is just used to control "green water", so they are sized appropriately.

If you want to use one of these types of units for parasite control, check out the recommendations for UV units on my dino thread.

All that said, I wonder if you really need a UV unit at all? You didn't mention anything about fish or algae or anything else as to why you wanted it.....just that it was on sale. Without a reason for using it, you can't really know what size to get or how to best install it. IMO consider taking a pass and get one when you need it. 👍
All said about management is correct and as for uv, is it something that I need? no but is it something that would be great to have on hand yes. I did decide to pass but only because it is undersized even for Algea control. Which would be my intention if ever needed. I guess when the time comes I’ll get an appropriate one for whatever that need is. All in all got some great responses and insights to uvs. Allot more people run one than I originally thought
 

Freenow54

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At a guess a pond UV might just be for algae so it would run at a low flow also possibly larger volume , maybe too large physically ?. I don't know I have seen them advertised just never bothered to read about them. You probably would only be able to use it for algae , in that case an algae scrubber would be the way to go if what I have read that they control algae in a way that it keeps it out of the main display
 

Australian_Reef

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I used a large pool UV over 10 years ago. It was massive. There’s nothing wrong with using one per se, uvc is uvc, but it’s hard to get any real idea of the actual UV dosage as it’s mainly for algae clarification for these units. If you get any manufacturer output measurements then you could extrapolate to the theoretical protozoan sterilisation dose. But as stated in the thread this is still a bit of an unknown. I now run a UV twist 57w on the manufacturers recommended flow rate. I have had no ich outbreak but it gives me an added sense of security. But if a unit doesn’t give you the data, not meaning just a wattage and a ‘for tanks up to ..’ it’s really a shot in the dark.
 

jahnje

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I take BRS with a grain of salt anymore. I used to watch them all the time but you must remember they are trying to sell you stuff . It took me a long time to find the information. Luckily there was a picture of the make and model. Assuming consistency the stated wattage is a little more than double the usable wattage assuming the bulb is UV-C rated
I'm happy Ryan has gone off and started "serious reefs" just for this reason.
 

Koty

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I have a UV on 24/7. I have a high bioload of corals, fish, and other marine creatures. My unit is the Vecton 600 25W, and it is connected to a tiny pump (slow flow, long dwell time under UV). The idea is that this UV system is designed to reduce the general bacterial count in the water column slightly but efficiently. We add a significant amount of organic matter, and in addition to the various export/filtration mechanisms, Bacteria in the water column should be controlled (IMO). I may be wrong. However, I did experience issues with fish and coral death that may have been related to the UV not functioning correctly.

WhatsApp Image 2025-12-08 at 17.23.50.jpeg
 

Freenow54

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I feel a UV is a total waste of money in a reef system but are great in a pond that you want to keep free of green water. 😎
I am going to put one in my pond next Spring because you endorsed it buddy I am Serious. But still going to put one on my tank as I already have the pump and pipe , and fittings. another DIY and then the under gravel filter , and an Algae scrubber. Currently finding out the limitations of bending Acrylic. Why can I mould in my jig a 12 inch piece but a sixteen expands bubbles and shrinks ? The 12 inch actually expands and eds up slightly longer Making rims for my DYI screen tops
 

mcarroll

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Finally a thread where I might get a proper answer. I am asking what you think. If running a UV is running an Algae scrubber the opposite approach ? IE should it be between one or the other ?
... you almost always want the UV filter to be the last thing in line of your filtration before the water goes to the tank. (i'm sure there are exceptions, but I can't think of any.)

I honestly have two. One for low flow and one for high flow so I get the best of both worlds. Either don’t do it at all or do it right. I don’t want disease or algae. That being said my tanks only 48 gallon so my two units cost less than most of the single larger units.
By the way, the one you have set up for parasites is also killing algae. 👍
 

Freenow54

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... you almost always want the UV filter to be the last thing in line of your filtration before the water goes to the tank. (i'm sure there are exceptions, but I can't think of any.)


By the way, the one you have set up for parasites is also killing algae. 👍
Why does my research tell me the flow for algae is drastically different than for parasites . I have already posted the research numbers earlier . I just am stating the written info do not know where you get your info am curious. I have stated a number of times to others That should be included in a post whether its an article Opinion or experience. I also read a lot of UV systems are not set up properly hence the article
 

Freenow54

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... you almost always want the UV filter to be the last thing in line of your filtration before the water goes to the tank. (i'm sure there are exceptions, but I can't think of any.)


By the way, the one you have set up for parasites is also killing algae. 👍
I intend to have mine a separate thing altogether. I have read that people put them in parallel with the return. I like my approach because I intend to have easy access and wont have to be on my knees to service . I am going to put it behind the main display with its own pump , and piping with a bypass to service three way to switch between parasite treatment and algae already set with control valves for GPH
 

Freenow54

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I feel a UV is a total waste of money in a reef system but are great in a pond that you want to keep free of green water. 😎
Please elaborate as to Why . With due respect I am interested not going to argue back . Your the mariner of the month with a trophy not me .
 

mcarroll

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Why does my research tell me the flow for algae is drastically different than for parasites . I have already posted the research numbers earlier . I just am stating the written info do not know where you get your info am curious. I have stated a number of times to others That should be included in a post whether its an article Opinion or experience. I also read a lot of UV systems are not set up properly hence the article
UV dose is what does the work. Flow rate and wattage are just components of that dose rate.

So when you have the UV dose so high (usually >90,000 units) to target parasites (high dose required because of their large physical size) then it's going to scramble *everything's DNA* up to and including what you're targeting.....including algae.

Not vis versa though.....a low UV dose for algae is going to have almost no effect on larger organisms like parasites.

I intend to have mine a separate thing altogether. I have read that people put them in parallel with the return.
If your goal is parasite control that's not going to work.....seriosuly kneecapping the filter by bypassing water around it so "basddies" can just cruise back to the display unmolested. 👎 Not good.

That is a fine strategy for algae or other less critical applications. (Algae isn't a killer like parasites, it's just ugly, so the whole priority is lower there.)

You really want 100% of your water running through the UV if parasites are what you are gunning for.

Maybe consider adding a micron filter to the system (maybe on both returns) to grab parasites mechanically? <50µ is fine....even 100µ might catch some. Ideally try to run <25µ to catch the most variety of things. (Smaller µ rating means less flow and quicker clogging, so selecting the right µ rating can be a balancing act until you get the right one for your flow and system.
 

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