Who uses a uv?

[Gazza]

Hi Peter,

Yes the fish sure do like it a bit murkier especially if the fish are in a pond which gets a lot of sunlight. Before i had my pergola i would get a fair amount of sun on the pond and it was interesting watching the fish to see what they would do. First thing in the morning they would be on the top but as the sun come round they would drop down and around the afternoon they would go along the front wall sometimes in a line to keep out of direct sunlight.

[ageinghippy]

I only turn mine ON if the water starts to `green up`. Once the water has cleared again, OFF it goes. No point in giving my money to the power company unnecessarily, I`d rather hoard it myself.


Chris (another one)

[MikeWh]

Hi...Most of my pond is inside & even the outside bit is well sheltered....I built a bit of a step (removable) over the UV as it is near the floor.....I thought I was running it all year, but on removing the step the other day I noticed a small amount of water dripping from the tube connections & no purple light glowing from it.....It could of been like that for months ....Although I voted that I run UV all year round....It was a complete & utter lie ..Mike

[eds]

Thanks for the votes guys. Meant to post the next bit earlier this week but just been too busy. Will sit down with my laptop later and do a proper post as it'll take too long on my phone!

[eds]

Right, sorry for the delay on this. Now I've had some responses I'll talk a bit more about my ideas and trying to see if I'm right!

I think that algae in a pond is probably triggered by similar things to that in a planted tropical tank. Let me give you a bit more information about planted tanks and why they get algae so that you can hopefully see where I'm coming from.

High tech planted tanks are systems designed to get high growth rates and allow you to grow any plants you like. They have medium to high lighting levels (2 watts per gallon upwards), injected CO2 (at 30ppm) so the plants have constant access to enough carbon to grow, they have high flow rates and efficient filters and finally they have nitrates, phosphates and other chemicals added, often daily, to the water to grow the plants. In these systems plants grow well and algae is rarely seen until something goes wrong with the system and it goes out of balance - e.g. someone doubles the lighting but leaves everything else the same or forgets to add fertilisers and the plants suffer. Algae is much more adaptable and as soon as conditions fluctuate they are able to profit and are true opportunists. One big trigger of algae is tiny amounts of ammonia (below the levels test kits can detect) caused by either lack of maintenance or in a unmature filter when starting the tank up.

So what does this mean for our ponds? Well I think it's the same things that may trigger algae in our ponds so I'm going to start by asking the people who don't use a UV to give us all a bit more information about their ponds if they don't mind to see if we have any things in common as to why we don't need to use a UV and maybe we can gian some ideas of how other people may be able to turn theirs off too.

So first of all my pond;
Size and design.
3,500 gallons in pond, stream and filter. Pond is 6ft deep and shelved, stream is 2ft deep and around 15m long.
Filter
Vortex, static K1 and then fluidised K1. Cleaned weekly in winter 2-3 times a week in summer. Small trickle filter.
Estimated 5% weekly water changes rising to 10% in summer.
Stocking
Around 35 small to medium fish. (No koi above 65cm)
Length of time established
12 years (filter last changed three years ago)
Other information
Planted
Not shaded by pergola or canopy but in partial shade thanks to hedge and trees.

[boogatee]

Ed, my setup is .....

2000 gallons (9000ish ltrs) ... 4ft deep .... shaded by a pergola covering entire pond

Filter 1 - Nexus 200 with 125ltrs of fluidised K1 and 50 ltrs Biochips - Aquamax 10K
Filter 2 - modified Biotec 12 screenex - foams replaced with partially submerged BHM - Aquamax 12K
Protein skimmer - running 24/7/365

3KW heater

Water changes 10% weekly - probably 49 or 50 times a year - miss 2-3 changes due to freezing temps, system is 6 yrs old

Stocking - 16 Koi (13 boys - 3 girls) ranging from small 55 cm - large 65 cm.

[Pond Life]

The main pond is in full sun all day so that has a UV on all year round. The front garden (goldfish) pond doesn't get as much sun and the water lily pretty much covers the surface in the summer so we haven't needed a UV on that for years.

[Brek]

Well two sunny days last week has seen my pond transformed into the black lagoon, seriously green and dingy, no uv on, tempted to leave it to see if it clears up on its own, although I think I tried that last year and it didn't,

For the record my pond is 1500 galls, gravity fed easy pod for mechanical/bio and bio max 25 for bio, 14 koi between 4 inches and 18 inches, params spot on i.e. not nitrite/ammonia readings, ph usually around 7.2 and tds sitting at 110.

[eds]

Mine has gone slightly green too as it does this time of year, but still no need for the UV IMO. Give it 2-4 weeks and mine has always cleared.

Was hoping the other guys who don't use a UV might chip in with some info about their ponds too.

[Paul24]

My pond is 2000gallons, with a Bakki shower as the main filter and an easy pod on the skimmer, a single pump turning the pond over around every 35-40 minutes. No UV is fitted and the pond has been running just under 3 years. Each year the pond has turned a bit too green (can't see the bottom) for 1-2months. Until last year the pond was unheated - it will be interesting to see how it goes this year, as the temperature has been kept over 15 deg C through the winter. It has just started to get a little green tinge, as daylight hours increase, along with feeding (now at 17 deg C). Water changed, perhaps 25% per week in summer, lowish stocking. Higher water changes can be used to make the water turn green.

The pond at my parents is 4000gallons, 10 years old, unheated, has a UV fitted but rarely used. Filtration is a single vortex with J-mat, followed by a 3-tier bakki shower. Turnover is once every 1 hour 40 minutes. The UV is switched on for maybe 6 weeks of the year to keep the pond clear, usually for 1 week at a time, maybe 1 week out of every 3 through the spring and summer. The water is 8 deg C at the moment and crystal clear. There is no food going in and the increase in daylight is not enough to get the algae started. I'm sure when I start to feed in a few weeks time it will soon start to turn green. Water change 5% per week, including through the summer.

I should say that both ponds are deliberately partially shaded with pergolas.

Paul T.

[Brek]

weekly update, very sunny day today, sun was on pond most of the day, nice green colour to the water, not showing any signs of clearing though, I will need a pergola on this year I reckon, one to keep the seagulls from harassing the fish, and two to keep the sun of the water, will leave till end of march and if not clearing on goes the UV.

[Brek]

another update with the sunny days this week, it is a real pea souper now, so uv up and running see how long it takes to clear, a while I reckon.

[eds]

Mine went slightly green and then cleared again. I have been making sure they don't get much food yet though. Has your greening up coincided with any change in feeding?

[Norseman]

Hi Guys,

I've had a uv on my pond for 5 years and in the past I always put it on from Spring to Autumn. But this year I have had the RO feed on for the last twelve months and I wonder if I will need it with the softer water.

Simon

[Gazza]

Hi Guys,

Its coming up to some interesting times now as we will start getting a bit more sun so lets see how the ponds go

At this moment in time mine is nice and clear but the cover is just being pulled back during the day and some put back on of a night but hopefully in a few weeks it will be off ready for the heatwave