UV flow rates for ich

[Blown]

Hi reefers,

So despite my best efforts qting every fish I have put in my tank since kicking it off 2 years ago a week ago I noticed what I believe to be ich on both my blue and purple tang. I have measured to tank to hold 115gal of water. I have had for the past year a pentair 25w uv which I have been running at 450gph 24/7 and when checked the documentation stated that it wasn't suited to treat ich and would need a bigger one. After going over the measurements there was no way I could fit a bigger pentair unit anywhere so I ended up buying a aqua ultraviolet 57w twist. When it arrived I was quite shocked at how much smaller it was than my 25w pentair being less than half the size. So with little faith in the 57w uv I have plumbed the unit in series with the pentair unit so it goes through the 57w then straight into the 25w. The flow rates have me confused though as a 50w pentair 3x the size calls for a flow rate of 158 gph to treach ich where as the aqua ultraviolet 57w calls for a flow rate of 1066gph. This makes no sense to me so I set it up based off the 50w pentair flow rate and have it at 2.8 gpm. After 1 week of treatment the infected tangs dont seems to be getting worse but I have not seen any improvements either.

Can anyone recommend what flow rate I should try running this setup at?

 

[lapin]

A UV works by sterilizing. The slower the flow the more (killing) effect it has. The drawback to this is if its too slow not enough water passes thru it per hour. 158gph x 24h= is about 4000 gallons per day. I think this would cover it. Not all the water will pass thru the UV but prob enough to do some big damage. Live foods and Nori will help the tangs.
Ich has developed to hatch out at night when fish are sleeping and still. Be sure you run it at night.

 

[Blown]

do you think that by having the 2 uv's running in series I could get away with a higher flow rate? I would also be curious what flow rates others are having success with on their aqua ultraviolet 57w

 

[piranhaman00]

First of all the saltwater parasite is crypto not ich, ich in freshwater is much easier to kill especially with UV.

Second, no one knows for sure what UV dose is required for crypto, the data is usually extrapolated from freshwater parasites. That is why all manufacturers state different flow rates.

Go as slow as possible but turn tank over 2x an hr IMO

 

[lapin]

First of all the saltwater parasite is crypto not ich

Darn those Cryptocaryon irritans. *-*

 

[Blown]

Pentair say you need 280 mJ/cm2 vs aqua ultraviolet 90000 µw/cm2 to treat crypto. Does anyone know the difference between the 2 measurements?

 

[Jay Hemdal]

do you think that by having the 2 uv's running in series I could get away with a higher flow rate? I would also be curious what flow rates others are having success with on their aqua ultraviolet 57w

Not in series - you should run them in parallel, and use separate pumps. The problem with UV sterilizers is threefold: some are simply underpowered and cannot kill ich tomites/theronts directly. Then, the residency time is a factor, while you are slowly sending water through the unit to get a good kill rate, the tomites/theronts are not getting pulled in fast enough and some have time to attach to the fish (running multiple units in parallel helps with that). Finally, there is a growing body of evidence that indicates that not all external parasites have a nice and clean life cycle, and some may be able to complete their cycle on the fish and never go into the water column to be killed by the UV (mostly I worry about velvet in that regard).

Jay

 

[Blown]

Thanks Jay,

What flow rates do you think I should run on each unit then?

 

[Jay Hemdal]

Thanks Jay,

What flow rates do you think I should run on each unit then?

Ah - sorry, I need a calculator for that. I think there is one online in the Pentair/Aquatic Ecosystems catalog.

Jay

 

[Malcontent]

Pentair say you need 280 mJ/cm2 vs aqua ultraviolet 90000 µw/cm2 to treat crypto. Does anyone know the difference between the 2 measurements?

Watts/area is fluence or light intensity. Joules/area is dose (fluence * exposure time).

 

[Largeangels]

IMO you are better off spending the time and effort to setup up a bare QT tank and treat with copper based meds and leave main tank fishless for a while. Even if you have the perfect flow rate on both UV's to kill every single thing passing through it you will never get all the parasites floating in your tank to go through the UV before they can infect a fish and repeat the cycle.

 

[Blown]

Watts/area is fluence or light intensity. Joules/area is dose (fluence * exposure time).

Is there a direct conversion between the 2?

 

[Blown]

IMO you are better off spending the time and effort to setup up a bare QT tank and treat with copper based meds and leave main tank fishless for a while. Even if you have the perfect flow rate on both UV's to kill every single thing passing through it you will never get all the parasites floating in your tank to go through the UV before they can infect a fish and repeat the cycle.

This is a longer term plan the uv is just to buy time. We are in the middle of summer here where temps are regularly 100+ and a qt big enough to house all my fish for that period would need to be in the shed. My tank is sps dominant and reasonably grown in and the scape would need to be removed to catch all the fish.