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Featured UV Flow rates?

Discussion in 'Help and Advice' started by Steve_bham, Jan 17, 2011.

  1. Steve_bham

    Steve_bham Guest

    RIght im a bit confused :eek: been trying to work out the optimum flow rate for the vecton 600 UV unit. looked at the instructions and also spoke to TMC and they say the idea flow rate is 1700LPH.

    From what ive read online this would be to high to be effect and a slower flow rate is needed.

    Is there some sort of calculation you can use? the tank will be 400L(ish)

    Thanks

    Steve
     
  2. Crypto

    Crypto Registered

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    Yep here is an example of the calculation (I'll make it into a sticky when I get the chance).

    You need to work out the volume of water the unit will hold.

    For a UV unit to be effective against White spot the water needs a specific contact time with the UV light, a 30W bulb produces 30,000 mw/uv/s.

    The lethal dose for WS is 72,000 mw/uv/s.

    If a unit produces 30,000 mw/uv/s then to achieve a lethal dose for White spot the water needs to be in contact with the uv for 2.4 seconds (72,000/30,000=2.4). So for instance for a UV unit if the volume of that unit is 1 litre then that litre of water needs to be kept in the unit for (72,000 UV dose required/30,000 UV dose achieved) or 2.4 seconds to kill the parasite. so the maximum flow through that unit is ((60/2.4) x 1) or 25 litres/minute or 1500 l/hr.


    The above volume is an example, you will need to cap the end of the unit before you fit it and fill it with water then empty it into a measuring jug, then substitute the volume in the formula above.
     
    Last edited: Jan 17, 2011
  3. Steve_bham

    Steve_bham Guest

    Thanks for info, ive just measured the Vecton 600 and it holds 0.5litres, and has a 25w UV tube. So if my maths is correct:

    72,000 / 25,000 = 2.88

    ((60/2.88)x0.5) = 10.42L/M or 625LPH

    Not sure that is correct as you say it should be 249LPH?
     
  4. jaimeomg

    jaimeomg Registered

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    I deliberatly ran my water very slowly through this unit. I think i had it at around 150lph.
     
  5. Steve_bham

    Steve_bham Guest

    I dont want to run it too slow as if i did that it would only treat the whole volume of the tank in about 2.6 hours.

    If i err on the side of caution and say the UV unit holds 0.4L thats 500LPH flow rate, so not sure where the 249LPH comes from.

    Ive double checked the volume of water it holds and it is def 0.5L
     
  6. Crypto

    Crypto Registered

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    Sorry Steve, I have no idea where I got 249lph, trying to find the source.

    Your calculations are correct....i've edited my post as to avoid confusion.
     
  7. Steve_bham

    Steve_bham Guest

    Thanks for your help, that formula is spot on just what i was looking for.
     
  8. craigey

    craigey Registered

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    I had the Vecton 300 & using the formula discovered it probably wasn't going to do much to kill off any ich parasites as I have a Rena XP 4 filter, which on it's lowest flow (using the tap provided) was outputting 360 lph.

    I measured this using a measuring jug & timed how much water flowed into it in a 5 second period. 500ml in 5 seconds (so 1L in 10 seconds) * 6 to get L per min (6) & times this by 60 to get 360 lph.

    When I got the Vecton 600 I took my measuring jug filled it up with 500ml of water, blocked the bottom of the UV filter & began pouring. It turns out the 600 filter can hold 300ml.

    Plugging these figures into the formula gave me the max flow rate that would kill ich, which is 375lph, so providing I have my tap on it's lowest setting the water should be getting a full 72,000 mw/uv/s + a little bit more! (I suppose the extra 15lph should compensate for any debris in the water).

    72,000/25,000=2.88
    ((60/2.88) x 0.3) or 6.25 litres/minute or 375 l/hr.

    Just thought it might be useful.
     
  9. Steve_bham

    Steve_bham Guest

    Yeah that's what I did took the hose tails off and filled with water. At worst case it holds 400ml of water at best 500ml of water. So using the formula would give me a rate of 500lph.
     
  10. Matt_collo

    Matt_collo Registered

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    I have one of these coming second hand, so the flowrate required is somewhere between 375 & 625 LPH, depending on the actual capacity of the unit.

    Before I plumb it in im going to fill it with water and then measure the volume.

    I will then work out the flow rate and control this with a ball valve?
     
  11. Mully

    Mully Registered

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    Hello guys :003:

    i run a 600 with a flow of circa 350-400lph works a treat turned my green water clear in a day or so
    Have a look at my thread its on there as is the supply pump rated at 550 lph turned down to about 2/3

    perfect, hope this helps
     
    Last edited: Jul 16, 2013
  12. royal1

    royal1 Registered

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    Just a quick question, how many times is the UV suppose to turnover the tank water if your lookign to kill WS, many thanks
     
  13. slash_halen

    slash_halen <span style="color:#088A4B">SPS Help & Advice

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    What UV do you have, and how many litres is your tank?

    The dose to kill cryptocaryon is 280,000 µWsec/cm2

    So for example the DD 39w UV produces an intensity of 33,000 µWsec/cm2, so the exposure time is 8.5 seconds roughly. However you also need to know how much water the UV holds, but assuming it holds 1 litre for example, then the flow rate would be 7 litres a minute ((60 seconds / 8.5 second exposure) * 1 litre) = 7 litres, which translates to 420 litres an hour.

    You can find the lethal dosage to various pathogens here: Microorganism UV Doses for UV Disinfection of Waterborne Pathogens in Aquaculture.

    and here: FA164/FA164: Cryptocaryon irritans Infections (Marine White Spot Disease) in Fish

    Unfortunately this is why a UV isn't the best option for white spot, especially with the nature and lifecycle of the parasite, but very efficient against bacteria and viruses.
     
    Last edited: Aug 28, 2014
  14. royal1

    royal1 Registered

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    thanks for getting back so quickly, i thought the lethal dose was 78,000 for WS as per the previous page.

    i have the vecton uv 200, it was for my old tank 200ltr but now its in the loft doing nothing.

    my new tank is the aquareef 300
     
  15. slash_halen

    slash_halen <span style="color:#088A4B">SPS Help & Advice

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    Unfortunately, the 78,000 figure sounds more like the dose for freshwater whitespot, seems very low for a saltwater protozoa.

    I've Google that figure out of interest and I know where its come from, and it does seem to appear a lot on UK forums, and I think Wombat (expert on fish health on another forum) was the source of that figure, but he claim to get that figure from OATA, however that is not what OATA say in their Bio Security Doc (p.73): http://www.ornamentalfish.org/wp-content/uploads/2012/08/Biosecurity.pdf

    They actually say 1,000,000 for some parasites.

    Here is some more info, the 280,000 figure according to this is the lower end of the recommended dose.
    http://edis.ifas.ufl.edu/pdffiles/FA/FA16400.pdf

    A good powerpoint presentation about UV's here too: http://www.google.com/url?sa=t&rct=...=aTHZPScNQE3fVeXQ-CuKag&bvm=bv.74035653,d.d2k

    Some simple stats: w Lim Corp. | Koi Pond Supplies, Pumps, Filters, UV Filters

    Sorry for the ton of info lol.
    But hopefully it will help :)

    I'll see if i can work out the flow rate for a vectron 200 for you when i find the info.
     
    Last edited: Aug 28, 2014
  16. slash_halen

    slash_halen <span style="color:#088A4B">SPS Help & Advice

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    Well TMC don't give you anything details about their UV's do they lol. I can't find anything about the dose.

    Not the best answer unfortunately, but going off that example of 420 litres per hour for a 39w UV, then I would say 87.5 litres per hour (420 litres / (39w / 8w)).

    However the DD one has a quartz tube which provides more light than a glass tube. So maybe go for something like 60 litres per hour based on 280,000 dose or 233 litres per hour based on a 72,000 dose.

    A complete stab in the dark unfortunately, I would have thought TMC would provide the dose for their UV's.
     
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