Setting up two UV sterilisers on one tank

[DavidJTawil]

I currently have a 150 gallon with a herbie overflow and a single line return which Ts of and splits into two 1/2 lockine returns. I’m looking to convert the herbie overflow to a bean animal (using the return line hole as the third required hole) and drill two holes in the back of the tank for returns. I’d like each return to have its own return pump. I have two aqua 40 uvs. One will be run as a closed loop utilising one of the drilled holes. The other I was either thinking of running it on the other return or off of a manifold and returning back into the sump.Looking to use one UV steriliser for fish parasites and the other for algea and bacteria - each with different turnover rates. Any suggestions? Should I be plumbing this differently. What size holes should I drill? How should I direct the flow from the return bulkheads? Is there any reason I should drill additional holes for other purposes or additional returns.

I appreciate all the advice,
David

 

[Gablami]

For your size tank, I think you should have both at slow flow. One 40w aquaUV is not enough for ich IMO. 80W at the appropriate flow rate is probably good.

Of course you could run one or both at high return flow rates until you have experience an outbreak. Then then down the rates in both to give enough kill dose.

I’ve got two aquaUV 57W on my 260 display. Both plumbed into return manifolds, dual return pumps.

 

[DavidJTawil]

Thanks for the advice. I believe, aside from wattage, contact time plays a large role in the effectiveness of the UV. The Aqua 57 watt UV appears to be a much smaller unit then the Aqua 40 watt - nearly half the length. Is there any particular reason that the 40-watt sterilizers won't do the job. It's rated with a tank size of 325 gallons and I have two. Also, I believe that your two oversized units are needed only because they are not plumbed in a closed-loop manner but rather are returning back into the sump. In your setup, not all of the water in your tank is getting processed through the UV while some of it is getting processed multiple times and that's where an oversized UV is needed. I understand that the implementation of the UV is widely debated and can be done in many different ways.



On a separate note, any advice on how big of a hole I should drill for a return?

 

[Gablami]

I’m not saying it won’t do the job. I’m just saying to have both run at parasite kill rates, as opposed to having one for algae (higher flow) and one for parasites (lower flow).

aquauv published recommended kill rate for parasites is 90,000uw/cm2. This is generally thought to be on the low end of dosage for ich. Many will use 270-280k uw/cm2 as a starting point based on a published study. If you do more research on this forum it’s not hard to find the link to that publication.

 

[DavidJTawil]

I believe that 180,000 uw/cm2 will kill parasites. Can’t that be achieved by simply tuning the flow rate down?

 

[Gablami]

I believe that 180,000 uw/cm2 will kill parasites. Can’t that be achieved by simply tuning the flow rate down?

Yes. If aquaUV is recommending 90, and you want to go to 180, divide their corresponding flow at 90 in half.

So according to this chart, it would be 483 gph for a 40W aquaUV for a 180k uw/cm2 dosage.

 

[ichthyoid]

I’m not saying it won’t do the job. I’m just saying to have both run at parasite kill rates, as opposed to having one for algae (higher flow) and one for parasites (lower flow).

aquauv published recommended kill rate for parasites is 90,000uw/cm2. This is generally thought to be on the low end of dosage for ich. Many will use 270-280k uw/cm2 as a starting point based on a published study. If you do more research on this forum it’s not hard to find the link to that publication.

What published study are you referring to?

 

[Gablami]

What published study are you referring to?

Who uses UV?!

Hi NeptuneGarden. sounds like you know the UV stuff. what would you recommend for 130 Gal of water volume ?

www.reef2reef.com

 

[DavidJTawil]

Based on this study, for my sized tank I’d need a 160 watt UV sterilizer.

Who uses UV?!

Hi NeptuneGarden. sounds like you know the UV stuff. what would you recommend for 130 Gal of water volume ?

www.reef2reef.com

 

[ichthyoid]

Who uses UV?!

Hi NeptuneGarden. sounds like you know the UV stuff. what would you recommend for 130 Gal of water volume ?

www.reef2reef.com

Ah, the University of Florida study which references UV rates for cryptocaryon irritans which “are anecdotal or extrapolated”? It only serves to cast doubt on anything other than the manufacturer’s recommendations. What that study does state is that a rate of 100,000 uWsec/cm^2 is ‘recommended’.

That kill rate of 800,000 uWsec/cm^2 referenced was based on a size comparison to another, unrelated, parasite. (Spotte 1997). Other rates are anecdotal at best. Show me a controlled formal study, as I can’t find one.

What is recommended by the manufacturer is what I would go with & have gone with for years. Also read their notes below the application table, as to type of use & plankton.

As for UV water purification I found, after a thorough review of the literature, that most of the recommendations are based on the single point application rates for sterilizing drinking water (not aquarium water).

That means 99.9+% kill rates, at one single point of contact. This does not represent any typical scenario encountered in marine aquaria. Our fish live in recirculating systems & have some degree of immunity, among other things.

Many, if not most, aquarists use oversized UV’s in an attempt to prevail against a poorly understood & much feared nemesis. Myself included, in the past. So, the premises used by some, for their application rates of UV in aquaria, is flawed imo.

I’d stick to the manufacturer’s table. It works & they have a vested interest in you being successful using their products.
My $0.02

 

[Gablami]

Ah, the University of Florida study which references UV rates for cryptocaryon irritans which “are anecdotal or extrapolated”? It only serves to cast doubt on anything other than the manufacturer’s recommendations. What that study does state is that a rate of 100,000 uWsec/cm^2 is ‘recommended’.

That kill rate of 800,000 uWsec/cm^2 referenced was based on a size comparison to another, unrelated, parasite. (Spotte 1997). Other rates are anecdotal at best. Show me a controlled formal study, as I can’t find one.

What is recommended by the manufacturer is what I would go with & have gone with for years. Also read their notes below the application table, as to type of use & plankton.

As for UV water purification I found, after a thorough review of the literature, that most of the recommendations are based on the single point application rates for sterilizing drinking water (not aquarium water).

That means 99.9+% kill rates, at one single point of contact. This does not represent any typical scenario encountered in marine aquaria. Our fish live in recirculating systems & have some degree of immunity, among other things.

Many, if not most, aquarists use oversized UV’s in an attempt to prevail against a poorly understood & much feared nemesis. Myself included, in the past. So, the premises used by some, for their application rates of UV in aquaria, is flawed imo.

I’d stick to the manufacturer’s table. It works & they have a vested interest in you being successful using their products.
My $0.02

Not saying it’s good data, in fact it’s pretty horrible data. And as you probably know, what is commonly quoted as the “university of Florida study” is actually no study at all, but more a review paper, summarizing and interpreting other papers.

But at the same time, as a hobby we learn from each others’ experiences, and the “group think” that the masses follow seem to recommend a higher dose than what the manufacturer recommends. It’s up to each aquarist what he/she wants to do. But I think everyone who is deciding to run UV should at least know about this article and the reasons why some recommend a higher UV dose for parasites.

 

[ichthyoid]

Fwiw,
If used, I would put the UV on a timer & turn it off at night. This will prevent frying the planktovores/pods that we should have in a healthy reef. As they tend to come out in the dark.

It would also be nice to see manufacturer’s share their UV data. However, being public companies, it’s necessary to protect proprietary information & trade secrets. They know precisely what is required to denature &/or kill common pathogens, algae, etc. using UV light.

UV works by disrupting the RNA in an organism’s cells, making it impossible for them to reproduce. The UV is absorbed by uricil molecules, one of just 4 bases contained in the RNA. This causes bonds in the uricil to break, changing it’s structure to what is known as a dimer & leaving the organism sterile. So, it’s not necessary to kill pathogens, just to ‘neutralize’ them.

Not all of the uricils absorb the UV & a few of the uricil’s which are changed revert back to a normal structure over time. So, the mechanism is not 100% effective. This is all dependent on statistical probabilities, but is predictable based on research done on a given specific organism.

Hope this helps

Comparison of UV-Induced Inactivation and RNA Damage in MS2 Phage across the Germicidal UV Spectrum

Polychromatic UV irradiation is a common method of pathogen inactivation in the water treatment industry. To improve its disinfection efficacy, more information on the mechanisms of UV inactivation on microorganisms at wavelengths throughout the germicidal ...

www.ncbi.nlm.nih.gov