Thread: Uvc

Are you after a UV for algae or a steriliser for bacteria etc?

Cut and paste from t'internet but makes sense to me. Be cheaper to put shade over the pond, if your 80w isn't touching the sides:

Ornamental Ponds: 1 watt per 1,000 litres (220 Gallons)

Fish Ponds: 2 watts per 1,000 litres (220 Gallons)

Koi Ponds: 4 watts per 1,000 litres (220 Gallons)

So as an example, a Koi Pond of 10,000 Litres (2,200 Gallons) would require a minimum of 40 watts of UV power.

I’m a fan of the TMC Pro Pond units, running 2 x110w on an uncovered 13k Gallon pond and they coped fine last summer

Originally Posted by Rutty

Can anyone advise on best UVC to stop green water. If I have to spend a £1000 on a UVC to stop green water then so be it
Pond is 6000 gallons in south facing garden
120 kg Bakki showers/ media, oase drum filter, 120 litres K1 media, skimmer, amalgam 80watt UVC - water parameters spot on

Wanting powerful UVC to kill green water, parasites and anything else to keep pond healthy

Please Help!

what are your ammonia, nitrite, nitrate, and phosphate readings, and what do you test them with?
what is your stocking level, number of fish, and sizes?
how old is pond, and the amalgam lamp?
did it work before or has it not ever kept the pond clear of algae?

standard flourecent UV lamps lose up to 50% of the effective wavelength and output when not running at optimal temperatures of 20C, either too hot or too cold.
which is very easy to go over 40C when they are sealed in a UV housing even with cold pond water running through them.

amalgams use a mercury amalgam to extend high output so they work at over 90% output even at high temperatures.
so you get double the effective UV wavelength of light at a similar wattage flourecent UV.

that said, sterilising a ponds water with UV light would need a hell of a lot of light, and ridiculous amount of contact time.
more than is really viable for 6000 gallons. roughly 1 watt per litre per hour.
so 6000 gallon pond roughly 27,000 litres turning over once per hour through a bakki shower, would need 27 kw of UV light

Or one good 110w unit on basis of my 2 going a pond slightly bigger than twice the size of yours . You do need to change the bulbs every year though. The amalgams look good but need to be contained in uv resistant plastic and I’ve never been convinced my drum filters are so haven’t risked it, especially having seen what I’ve does to plastic in ozone systems