Is there a minimum flow level required for UV sterilizers?

[madreefer11]

I have a Pentair UV 50 Watt and it says suggested flow is 1560GPH and maximum is 1980PGPH. Can i run the flow at belwo 1560GPH?

 

[Doctorgori]

Short ans. Sure you can split the difference, but thats like saying using 1/2 of a birth control device is worth it ...
BRS Has a vid does a much better job of explaining UV flow.... a search will yield plenty of material 4ya....happy reading

 

[Waters]

You can run the flow at whatever speeds you want.......different things require different contact time with the light to be effective though (along with bulb strength, clarity of the glass tube, etc). For example, parasites need longer contact time (slower flow) than bacterial issues. As @Doctorgori stated, I normally try to keep it somewhere in the middle.

 

[madreefer11]

My point is if you run at lets say 330 gph ( for Protozoa) would it be also good for algae?

 

[Doctorgori]

My point is if you run at lets say 330 gph ( for Protozoa) would it be also good for algae?

Re-read my 1st post...never sounds as intended on re-read...weird ...
Anyway, I thought the current conventional wisdom with UV gizmos was that whatever GPH works Killing one thing doesn’t work so great for killing the other ... so if its its optimized for algae it isn’t effective for Protozoa and visa versa .... might be a better ans out there

 

[ca1ore]

Sterilization (parasites mostly) requires slower flow than clarification (algae, bacteria). Slower flow will obviously also affect algae and bacteria, but getting enough of the tank volume through the unit per hour becomes problematic. That's why larger UV units are generally recommended if sterilization flow rates are desired. The lowest flow through any UV in theory would be enough to keep the bulb quartz sleeve cool …. that is likely much lower than any rate you might pick for sterilization.

 

[Malcontent]

In a recirculating system, you don't want flow to be too low. Once flow rate is above a certain flow rate, there really isn't any difference.

The idea that you need slow flow rates or rates specific to different types of organisms is a relic from single-pass UV sterilization.

 

[ca1ore]

In a recirculating system, you don't want flow to be too low. Once flow rate is above a certain flow rate, there really isn't any difference.

The idea that you need slow flow rates or rates specific to different types of organisms is a relic from single-pass UV sterilization.

I have no idea what that means .... care to elucidate.

 

[Malcontent]

I have no idea what that means .... care to elucidate.

UV Sterilizers, which unit to choose and why?

Not sure where you got the aqua uv #s but from their own site the 57 watt is at 90,000 µw/cm2 (EOL) GPH: 1,066 meaning to get 180,000 it would be at 533gph it appears this is calculated with 100% bulb strength. Many brands use 80-90% for the calculation. The biggest difference between...

www.reef2reef.com

 

[Miller535]

To me it is very simple. Parasites need slow flow, we all know that. The reason that they recommend high flow rate for bacteria and algae, so that you achieve high tank turn over rate has to do with that rate that algae and bacteria reproduce. They reproduce so quickly that you have to turn the tank volume over quickly and a lot. And unlike parasites, they do not need nearly the contact time to become sterilized. I truly feel most people do not understand what a UV even does. Most people seem to think that it kills the organism, it does not, it sterilizes it so that it can not reproduce. For algae and bacteria you are essentially trying to turn over most of the population through the UV faster then it can reproduce. And in the case of Algae and bacteria, generally a few hundred gallons an hour is just not nearly fast enough.

 

[Miller535]

UV Sterilizers, which unit to choose and why?

Not sure where you got the aqua uv #s but from their own site the 57 watt is at 90,000 µw/cm2 (EOL) GPH: 1,066 meaning to get 180,000 it would be at 533gph it appears this is calculated with 100% bulb strength. Many brands use 80-90% for the calculation. The biggest difference between...

www.reef2reef.com

I looked at this and I am not sure what this shows. E Coli and salmonella are not in reef tanks so anything with sterilizing them seems moot. When people talk about flow rates for bacteria and algae they do not mean every single type of bacteria and algae on the planet, but the common types we see in reef aquaria.

 

[ca1ore]

UV Sterilizers, which unit to choose and why?

Not sure where you got the aqua uv #s but from their own site the 57 watt is at 90,000 µw/cm2 (EOL) GPH: 1,066 meaning to get 180,000 it would be at 533gph it appears this is calculated with 100% bulb strength. Many brands use 80-90% for the calculation. The biggest difference between...

www.reef2reef.com

LOL …. had forgotten about this. Seems like a good theoretical treatment on the subject with very little real world application …. at least for a reef tank. How do you define a recirculating versus single pass UV installation? Depending upon that definition, every reef tank would be considered recirulating. Would be more useful to find a similar study on parasite affect, rather than bacteria. Nice to see some science through.

 

[Dj City]

simple answer...

YES

Flow matters!
Pentair has specific instructions on flow rates for the UV to be effective.
Don't waste time or money if you don't intend on doing it right.
Property installed UV with correct flow actually works.
Improperly installed or incorrect flow Will Not Work At All


Hope this helps.

 

[Malcontent]

To me it is very simple. Parasites need slow flow, we all know that. The reason that they recommend high flow rate for bacteria and algae, so that you achieve high tank turn over rate has to do with that rate that algae and bacteria reproduce. They reproduce so quickly that you have to turn the tank volume over quickly and a lot. And unlike parasites, they do not need nearly the contact time to become sterilized. I truly feel most people do not understand what a UV even does. Most people seem to think that it kills the organism, it does not, it sterilizes it so that it can not reproduce. For algae and bacteria you are essentially trying to turn over most of the population through the UV faster then it can reproduce. And in the case of Algae and bacteria, generally a few hundred gallons an hour is just not nearly fast enough.

Not slow flow, a higher dose. Flow rate and turnover rate are inversely proportional so the dose is the same. If you go too fast, the parasite is still dead. If you go too slow you treat less water but over-sterilize the water you do treat giving the parasite more opportunities to find a fish.

 

[Malcontent]

I looked at this and I am not sure what this shows. E Coli and salmonella are not in reef tanks so anything with sterilizing them seems moot. When people talk about flow rates for bacteria and algae they do not mean every single type of bacteria and algae on the planet, but the common types we see in reef aquaria.

It's proof of concept.

LOL …. had forgotten about this. Seems like a good theoretical treatment on the subject with very little real world application …. at least for a reef tank. How do you define a recirculating versus single pass UV installation? Depending upon that definition, every reef tank would be considered recirulating. Would be more useful to find a similar study on parasite affect, rather than bacteria. Nice to see some science through.

Single-pass is like a drinking water plant. One pass through the UV and that's it.

It's really about dosing not the organism you're targeting.

There aren't any studies on parasites that I know of but the fact that they don't exist doesn't disprove my point. The fact that you can fractionate UV dosage with some organisms makes it more likely that you can with others as well.

 

[Aardvark1134]

There are limits to this. Example, I can go to the beach 10min a day without sunscreen for years...but I can't sit on that same miami beach with no sunscreen for 12hrs straight without needing a hospital for terrible burns. The exposure must be enough that it does more damage than can be healed before the next exposure. This # will clearly vary by target.

 

[Miller535]

It's proof of concept.



Single-pass is like a drinking water plant. One pass through the UV and that's it.

It's really about dosing not the organism you're targeting.

There aren't any studies on parasites that I know of but the fact that they don't exist doesn't disprove my point. The fact that you can fractionate UV dosage with some organisms makes it more likely that you can with others as well.

It would be proof of concept if all bacteria could be sterilized and or killed the same way. Suggesting that bacteria that are so drastically different can all be treated the same way would be like suggesting that all viruses can the sterilized or killed the same way. You have to compare apples to apples.

 

[Dj City]

There are limits to this. Example, I can go to the beach 10min a day without sunscreen for years...but I can't sit on that same miami beach with no sunscreen for 12hrs straight without needing a hospital for terrible burns. The exposure must be enough that it does more damage than can be healed before the next exposure. This # will clearly vary by target.

One of the best descriptions for flow rate I've heard.
Well said!

 

[DrMMI]

In one of their videos, BRS mentions that you can use one UV for both parasites and algae if you grossly oversize the UV for a given tank. They don't mention anything more than this. Does anyone know what flow rate to run the UV if you do that? Would you run it at the slower parasite rate or the faster algae rate?

 

[Dj City]

In one of their videos, BRS mentions that you can use one UV for both parasites and algae if you grossly oversize the UV for a given tank. They don't mention anything more than this. Does anyone know what flow rate to run the UV if you do that? Would you run it at the slower parasite rate or the faster algae rate?

I think it would be the faster flow rate. Personally, I would just use the appropriate size and let it do it's job.
If i had a ick problem, I would use the slow flow until I had a handle on it then go to higher flow.
Much less expensive.