I built a 20 000L koi pond in FEB/MAR this year and its been running perfectly until now. It used to be crystal clear and now suddenly there is so much green algea that visibility is very poor.




building...




inspecting...




more building...




almost there...




and done




crystal clear water




and a full pond pic




filtration




and now today




more of today



Filtration:
110mm bottom drain
Settlement chamber(+-1000L)
Auto-topup
Pump: speck 750W
3bag koi pond sandfilter (koi pond type gravel)
Ultrazap(big one) (bio balls and some sponges inside)
2x 40mm returns

Gerald's (garder) maintainance schedule:
Daily leaf skimming with the net (theres hardly anything)
Daily sweeping anything on the bottom into the dain (again hardly anything)
Daily backwashing and rinsing of the filter
Weekly draining of the settlement chamber (5% water change)
Weekly cleaning of the pump
Monthly removal of the filter gravel and washing it in a huge basin with pond water only
Monthly removal of the filter material in the ultarzap and washing it in a huge basin with pond water only

The water has been crystal clear up until two weeks ago. Now there is a huge algea bloom.


My old koi pond was 7000L and ran a 2bag filter, Ultrazap and a 450w speck pump and it never had algea issues. It had a UV light in the beginning, but I never replaced the globe so it has been running with out UV for years. It now houses commets and is in perfect condition. It has the same mantainence schedule as the other pond and was my trail pond before building the big one.


I have just under 40 koi, 4x 40cm, 8x20cm and the rest 10cm.

My fish are happy, I just dont like not being able to see them clearly.

I need some advice as on how to proceed.

Dan,

1. The Bio filter is too small (the one in the pix is a 25lt = 12000lt)
2. Only clean your bio filter once a year (By cleaning it every week, the bio filter will never "grow mature.”)
3. Over stock (only 500lt per fish)

I would ad another Ultra Zap 25lt Bio Filter to the system. Maybe even bigger as your pond is in direct sunlight.
Keep from over feeding.
Do more water changes, and check your water parameters while the bio filter grows mature.

You put all the effort into the building of a stunning pond, why then neglect the filter system?
The filter system is the heart of the pond, the stronger the heart the better the pond work!
Rather, over kill on a filter system. It will not do any damage.

All my ponds have “over kill” filter systems. This is my filter system on my 10 000lt pond;
1,1kw pump
1 x 3bag sand filter
1 x 5bag sand filter
2 x 25lt Ultra Zap bio filters

We had a lot of rain the last few weeks in the Cape Town area, and that created a lot of green ponds.

One of my clients who had an auto top-up also struggled with green water. He had a leak and never realised that because of the auto top-up. That created a situation where new water was added on a daily basis, adding nutrients to the pond every day, and created a green pond.

I agree with Pieter, you should increase your filtration, lower your stocking levels and you definately clean your filters too much. The nutrifying bacteria have to develop.

I would also add a UV light. 30 Watts should be fine. When your water is clean again, you can put it off.

The rainy season should be over now (Western Cape), and that will also contribute to a clearer pond.

PS! Very nice setup you have there.

silly question: I had this happen, is the UV working? when last did u chnage the light?

Cool,

Thanks for the replies.

So the plan is to get another ultrazap, the biggest one I can find. 25L or bigger.

Make sure that I have no leaks.

And then if the water doesn't clear add a UV light, not really a UV fan, but will give it a try.

Adi wrote:

silly question: I had this happen, is the UV working? when last did u chnage the light?

I dont have a UV on this pond as I never used the one on my previous pond. Seems like its time to get one though.

They work wonders......

Dan,

No UV light is needed, if your filter system is working!

Pieter J de Villiers wrote:

Dan,

No UV light is needed, if your filter system is working!

Thats what I wanted to hear.

I must sort out the filteration then.

Dan,

Yes...................the filter system is the solution.

Pieter & the rest

In Dan's case would it not be better to get a UV light, my reasoning is the following, I have just setup my pond, it's 8000lts and I have a .75 speck pump, 3 bag filter, 15lt ultra zap and a 15w UV, now this weekend I'm adding another 25lt ultrazap to the system. Ultimately I dont want to use a UV light, but from what I've read it takes a good year for the bio filter to establish themselves. So my thinking is that I put a UV light on now, the life of the globe is 9 months, so by the time the globe is klaar my biosystem should be in full swing and I should not need to use it any further.

Would that not be a good step to take, because as it stands I'm sure Dan will still have water clarity issues as his bio filters are no where near established and you can clearly see that this pond gets alot of sunlight.

Just a thought

I agree 100%

A UV light is a waste of money!
It only works 100% for about two weeks, after that it is useless!

One of my clever friends decided to buy a new UV light tube instead of upgrading his filter system. Phone me after about a week and told me that the light is not working and that he thinks the tube is faulty. So I went there to help him reinstall a new one.



This is the photo of the two tubes; the one week old one is on the left, notices the sediment on the glass. This dirt deposit will increase over days and the “tube light” will not be able to get through to make any impact on algae passing it.

The bottom line is this; the two tubes cost him more then R 1000, an extra filter with media would have cost him about R 750.
Now he is going to upgrade with an extra filter!
Who was that disciple in the bible..............Thomas?

There is a few of them here

So I've deceded to get another 25L ultrazap and a another 3bag sand filter.

I was at two petshops yesterday and they both wanted around R1200 for the empty 25L ultrazap.

Anybody know where I can get one at a decent price and what exactly to fill it with as well as the 3bag sand filter. (Cape Town area)


Dan

could help u in the JHB area.....