Is there a minimum flow level required for UV sterilizers?

[Saltees]

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 would oversize the UV and run it at the Parasite dose. I’m getting a DELTEC 80W UV rated at 3600L/H for Algae and divide it by 2.4x to 1500L/H for Parasite. 1500L/H is about 3x the volume turnover for my RSR500 Peninsula (120G).

 

[vetteguy53081]

Yes and most manufacturers Will post that info

 

[Aardvark1134]

What they ment is you usally want 2-3x turnover to get the fast multipliers or 180K for paracites, but by getting a bigger one you could get one that could manage 180K@2-3x turnover and accomplish both goals with just that one.

 

[Saltees]

What they ment is you usally want 2-3x turnover to get the fast multipliers or 180K for paracites, but by getting a bigger one you could get one that could manage 180K@2-3x turnover and accomplish both goals with just that one.

That’s exactly what I did!

 

[Miller535]

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?

There is one issue with this. And that is that a grossly oversized UV ends up being a heater that never shuts off. I have a 55 watt lifeguard on my 125 gallon which is rated for up to 350 gallons. And I have to keep that room very cool, or my tanks starts getting hot. Many who go "grossly" over sized either end up getting rid of their unit or getting a chiller. I am not saying not to do it, but it's something to keep in mind.

 

[bezj]

Hi. How did you set the DD 80 up? The reason I ask is that I have a TMC vectorn 600 on my pump returnResearch suggests this is level 1 at best and a nightmare to remove so thinking about adding a DD 80 on a closed loop from the display tank. Have ICH at the moment and hydrogen peroxide dosing is just holding at bay.

 

[Saltees]

Hi. How did you set the DD 80 up? The reason I ask is that I have a TMC vectorn 600 on my pump returnResearch suggests this is level 1 at best and a nightmare to remove so thinking about adding a DD 80 on a closed loop from the display tank. Have ICH at the moment and hydrogen peroxide dosing is just holding at bay.

I ran my Deltec (DD) 80W off my return pump with an 1” flow meter immediately after before entering the display. Thereby ensuring the perfect protozoa killing flow rate of under 1500 LPH for RSR500P! I’ve also have an inline ORP meter, whenever the UV is on or off, I have observed an immediate difference of 40-50 units in the ORP.

 

[Sarlindescent]

IMO, there is basically no minimum, just a measure of efficiency to effectiveness. Certainly organisms need X amount of energy to be killed by uv. To little and they will survive, too much and they will die half way through the reactor.

Ex (not real numbers):
Algae needs 2 units of uv to die
Cyano needs 3 units
Dinos need 4 units
Ich needs 9
Flukes need 11

If you run your uv flow very slow at a rate of 36 units per pass, it will kill everything above from the water it circulates, but it is only touch 1/4 the tank volume per hour.

If you run your uv flow at 11 units per pass, it will also kill everything above, but will circulate 3/4 of your tank water per hour, making the uv more efficient.

If you run your uv flow at 3 units per pass, it will only kill algae and cyano, but it will circulate 3 times your tank water per hour. This will make the water very clear, but will not solve any parasite issues.

The higher your flow rate, the less uv units per pass. The lower the flow, the more units. Determine what you want to kill and set it there.

 

[Belgian Anthias]

A good germicidal UV unit can sterilize the water in the unit, it won't do much in the tank, it's all about competition. UV damages DNA and prevents reproduction. Space and nutrients not used due to the reproduction limitation of irradiated organisms will be quickly taken up by the competitors in the aquarium.UV can be dangerous in the sense that if not everything is killed, pathogens will be selectively favored, which can have a major impact on the evolution of a small closed community. Some organisms are allowed to reproduce, some are not, so the site and the nutrients will be used by? Selective use of germicidal UV for a specific purpose is therefore not recommended. It's all or nothing. Selective use of UV germicidal in a small community such as an aquarium can be dangerous!
Not yet mensioned is the working temp. The lamp used must be powerfull enough to kill 99.9% at the desired flow rate. Each type of germicidal UV lamp has its specific ideal working temperature. A unit not powerfull enough must be operated at a very low flow to produce the desired dose irradiation, in the case the temp may become very high. Flow must be manageable for keeping the UV lamp temp in the ideal working range.

An other aspect is the mounting space, not all types of UV lamps are suitable to be used vertical and horizontal. Pellet Amalgam UV units can be used both ways.

ref: MB CMF De Haes 2007 - 2017