U.V. help needed

[Ru55]

Hi Iam looking to buy a inline U.V. for my pond which is mainly goldfish but with a few koi Iam struggling to work out what exactly I need and wonder if anyone could help please !
Pond 2485 ltrs
Pump 2500 ltr ph ( not shaded receives a fair amount of sunlight)
I have read that I should be around 40w mark for sterilisation maybe even 55w to over compensate but when I read the minimum flow rates for this on some U.V’s Iam way off the mark, Iam struggling to understand the more exposer (dwell) can have an adverse effect on results, so how important is it with the minimum flow rate I understand the max as to make sure the water gets enough exposure. Hope this makes sense Lol thanks in advance for any help with this as it’s now doing my head in lol

 

[Lisak1]

Welcome to the GPF!

Let's start with - why do you feel you need UV filtration?

 

[Ru55]

Welcome to the GPF!

Let's start with - why do you feel you need UV filtration?

Hi thanks for reply! I have a real problem with algae and of late blanket weed and not sure what else to do !

 

[Lisak1]

UV will only address floating algae - what is often called "pea soup water".

Tell us more about your pond - size, how many fish and what kind, do you have plants, what kind of filtration, etc.

Algae is a symptom of too many nutrients in your pond - either too many fish, too much organic waste or not enough plants to help with biological filtration. Any of those sound familiar?

 

[Ru55]

UV will only address floating algae - what is often called "pea soup water".

Tell us more about your pond - size, how many fish and what kind, do you have plants, what kind of filtration, etc.

Algae is a symptom of too many nutrients in your pond - either too many fish, too much organic waste or not enough plants to help with biological filtration. Any of those sound familiar?

Most likely all sound familiar! Lol .. 2485 litres 2 koi one abut 12 inch one about 8inch and I’d say around 60 gold fish ranging from 3 to 5 inch small Lilly patch and one Iris laevigata in one corner 3 air stones and a waterfall.
The water has been so green you could not see more than an inch in... I running a pontec 10000 whIch has been fairly good up til now, water never been crystal clear, we have a south facing garden and pond has no shade so really is exposed ...

 

[Lisak1]

Oh my. Yes. You are WAAAAAY over stocked. People blame sunlight for algae, but really all the sun does is make it greener. You're feeding the algae with all the fish waste in your pond.

Your pond is too small for koi, so I'd start there. Find a new home for those two. Goldfish are a better choice at just over 600 gallons, but you may need to reduce your numbers there, too. And MORE PLANTS! Lots and lots and lots more plants!

The algae is sending a message, but it's also helping to deal with the issue. If you eradicate the algae but don't address the cause you will have an even bigger problem on your hands, and likely will end up losing some fish. The reason this problem develops after a few years is the number of fish have likely increased as well as the size of the fish. Check this chart to see the difference in waste output between a 3 inch goldfish and a 12 inch koi - it's eye opening!

Koi Length and Weight - Ammonia Produced, and Waste Produced

This chart also lists koi weight by weight and how much ammonia and waste they produce. Koi get heavier as they grow and produce more ammonia and waste.

russellwatergardens.com

 

[Ru55]

Oh really! The previous owner had koi in there and we only just lost one he’d left at 36yrs old!
I really don’t want to get rid of koi as there were a present, I’ll have to look into getting rid of gold fish !

 

[brokensword]

switch from being UVu to BFC!!!!

 

[Mmathis]

The reason you think you need UV is because you have goldfish and koi in a 700 gallon pond. Your pond is too small for koi. You are overstocked and your biological filter isn’t able to keep up with the bio load — IOW, you have more nutrients in your pond than you have beneficial bacteria. Your best bets are to rehome the koi; build a larger pond; add more biofiltration; add tons of plants.

 

[j.w]

@Ru55
Got a shovel, start digging for that bigger pond! Your fish will love you for it

 

[Lisak1]

You can try to keep the koi, but 700 gallons for two koi is like trying to keep a whale in your bathtub. You'll be able to keep him wet, but he may not be terribly happy. If a koi lived in the pond for 36 years, someone must have been doing something right. Or got really really lucky.

 

[addy1]

If a koi lived in the pond for 36 years, someone must have been doing something right. Or got really really lucky.

Or it was one of those that did not grow big!

Welcome to our forum. A nice bog filter will really help you and your fish

 

[Lisak1]

Or it was one of those that did not grow big!

True! We had a couple of koi that were no bigger than some of my big comets!

 

[poconojoe]

Wow!
Too many fish!
Nature put the algae there to protect the fish.
The algae is feeding on all those excess nutrients that are formed from the fish waste.

You need more filtration, lots and lots of plants or better yet, a bigger pond.