Ultraviolet Light Systems

[ILLUSN]

DeKa do the new Jebo's have thier output stated on the units? I'm also looking for a UV for a 1000L tank with a flow rate of 1100l/h I want a UV dosage of atleast 90000uw

[Hooked]

Hi guys,
I'd appreciate if anyone has any recent experience/advice with the current units on the market. I'm after two units. One for a 400lt grow out tank that has two Eheim 2217's on it that are "rated" max flow of 1000lt/hr each.
Also a unit for an 1150 litre tank that has two Eheim 2080's on it that are rated max flow of 1700lt/hr each. (Both tanks spray bar holes are drilled out to reduce the velocity of the outlet flow )
I've had bacterial problems (fish were peppering and losing condition) that had not been helped (were mainly caused by) by overfeeding a little. I've got a better handle on that now and both tanks are doing much better.
The stainless bodied units seem to be a good idea.
I appreciate that the water needs time to dwell/be treated by the UV and am concerned I may have too much flow for a unit suited to the capacity of the tank? Or rather I need to buy a unit suited/sized to the flow rather than the capacity of the tank in this case?
If someone could please explain the 90000uw minimum that Illusn was good enough to recommend, would be great.
Any advice would be greatly appreciated,

Cheers

[ILLUSN]

Hooked, you need to use real world flow not max flow eheim 2217 = 600l/h 2080 = 1200l/h

no manufacturer will tell you this you need to get a bucket and calculater.

have a read through Pb's post 7 posts above its all the data you need, remember UV exposure time is dictated by how much water flows over the bulb not on how big the tank is.

[Hooked]

Hi Illusn,
Yep, understand the flow variation. I just put up the max as was all that was on the unit. Thats why I put it in "inverted" commars. I'm aware its never what you end up with after filling with media, hose length etc.
Just wondered if anyone had any updated info or recommendations mainly on units. But thanks for letting me know probably around 600 and 1200.
You are usually so good at explaining the more technical areas that I thought you may be able to shed some more light (pardon the pun) on the part that I obviously must have missed. I'll read it again,

Edit: Jothy, its the uw part I would really appreciate if you could explain. I understand its a unit of measurement and very important to have at least 90000. Just, I cant seem to find the exact clear meaning here. I'll jump on Google later also when home.


Thanks for your help,

Cheers

[Hooked]

uw = microwatt, got it,

Cheers

[DeKa]

Good to have you posting again DeKa.

I'm in the market for a top of the line UV for a 300 litre tank. What would you recommend?

Hi Merrilyn,
The general rule of thumb is to sterilise, you need to pass the water by the UV lamp at 1/4 the rate for UV Clarification. This means slower than pb's suggestion of 1/3 the rate. Based on the specs of the Aqua Nova 18W UVC this means you need water passing the UV lamp at 750L/hr rather than the UV Clarification recommended rate of 2500L/hr.

What this means is you need to calculate your pump's flow rate (which should be pretty close to the actual rated flow for an aquarium as there's only drag from the tubing, no actual lift) and then determine the right UV unit to use.

One other thing to note is the cheaper Aqua Nova models don't have a turbolator so the water doesn't get as much dwell time.

DeKa do the new Jebo's have thier output stated on the units? I'm also looking for a UV for a 1000L tank with a flow rate of 1100l/h I want a UV dosage of atleast 90000uw

What do you mean, 'stated output'? Yes, the large one is 75w output, just like a car engine may be rated at 150kw output.

I think you need to provide some clarification (no pun!) on this 'microwatts' term. You can't dose something unless you say how many units per quality e.g. millilitres per kilogram (for liquid medication as an example.) I suspect what is being discussed is probably something like microwatts per millilitre per second.

You'll need to confirm this understanding before any of us go any further.

[ILLUSN]

no worries DeKa I will try and clarify. Hooked this is the simpliest way i think i can try and explain UV sterilization.

The germicidal output of UVC is measured in micro watts (uW). Diffrent organisums have diffrent lethal dose (LD) mostly determained by the size of the organisum and the material that consitutes its outer cell wall. UV light must penetrate the outer wall of the organisum and destroy NOT JUST MUTATE the DNA within the cell/virus/nucleus.

The output of any given UV bulb should be measured in microwatts per second per square cm.

What this means is that a given bulb will emmit X ammount of radiation in 1 second across 1 square centimeter.

PB was nice enough to list the effective kill dose for various organisums if you look through his post you'll see small vegitative (activly dividing) bacterial cells have a lthal dose of 3000-10000uw/cm2/second. Bacterial spores and algae 25000-50000
naked viruses 20000- bigger/enveloped viruses 400000 and so on.

Newer generation germicidal UVC tubes that are either ionizing (ozone generating) or non ionizing are being used in the higher end units, these are they same type of tubes I use in my lab for fragmenting DNA prior to PCR work.

The effective output of such bulbs varies due to specific the test conditions. e.g Emporer aquatics test the out put of their bulbs at 1.5 inches from the bulb (housing is 3 inches in diameter) and uses this value of uw/sec/cm2 to calculate flowrate for a 30000 uw/s/cm2 dosage. in addition they assume a transmittance rate of 80% (green water), ie 20% loss in output through water.

From my understanding Aqualtraviolet measure their output at 1 inch from the bulb (housing size is 2 inches in diameter) and assume a 99%? transmittance through water and base their dosage tables on this data.

both manufactures use almost the same bulb so watt for watt they are almost equivilant but diffrent specifications on the units (diameter and hence "depth" of water, + assumed transmittance rates) give the 2 companys very diffrent usable ranges.

In a discus tank the water is never green its always super clear so i believe its safe to assume a transmittance rate of atleast 90%.

my question to you DeKa is

Do you have a stainless steel unit that will give me a uv dosage of 90000 uw/sec/cm2 at a flow rate of 1100l/h assuming i have a transmittance of 90% -99%?

I think stainless would look very good as I'm building a water cooled stainless LED light and figured i could incorporate the UV unit into it.

sorry for not being more specific.

[Hooked]

Hi Illusn, Hi DeKa,
Illusn, thank you for taking so much of your valuable time to explain that all to me . I can't thank you enough.
My very best regards,

Cheers