North Wales Koi Club Forum

whats the best thing to get rid of green water i have tried loads of stuff and nothing has worked.

Hi,
What size UV have you got? Is it too small for the size of pond, the recommended size is 10watts to 1000gals, but you might need more if the pond is in full sun.
When was the bulb changed last?

Dave.

i got a genie 3000 ponds 3feet deep and its in full sun but coved in loads of floating plants dose barley straw help clean the water if so i have put some in to try

Hi,
A green genie filter has a UV of 8 watts, that is right on the limit for your size of pond,with it being in full sun I would recommend a bigger UV.
Also to be perfectly honest the filter is not really for Koi ponds only goldfish ponds.
Remember the smaller the pond the better the filtration has to be.
It is no good chucking in things, to try and combat green water, the right size UV will do this. Another thing to try is to put a pergola over the pond.

Dave.

thanks for the help

Hi,
The main things that cause green water are:
-too much direct sunlight on the pond.
-Too weak a UV (UV light damages the single cellular algae, and makes them clump together).
-Insufficient filtration to mechanically remove the clumped algae or...
-Insufficient filtration allows build up of Nitrates and Phosphates in water. Algae use these as 'food'.

If you treat the pond with an algicide without taking care of the above, then the algae just grows back in a few days.
Barley straw will only reduce Blanket week, and has little effect on Green water (Unicellular algae).

Martin

i have just got a new filter box a Hozelock Ecomax 9000 are they any good

Gaz
How big is your pond and what Pump etc do you use?

I've not used the Hozelock Ecomax 9000, but my guess is it may struggle with keeping a Koi pond clean.

Martin

the pond is 7 feet long 6 feet wide 3 feet deep i think the pumps a maximus 3000

Gaz,
I reckon your pond is around 787 gallons, and the Hozelock filter claims upto 2000 gallons. However !!!
All should be OK but you will not get the water clarity and overall water quality with a pump fed system compared with a Gravity fed system. Your pump will grind up solids, and make them harder for the filter to 'seive out'.
Also, The water plants you mentioned may have Positive and Negative issues:
POS+ They help abosrb Nitrates and this can reduce Algae. They also produce O2 in the daytime that the fish will use.
NEG- They used up O2 at night, which fish "Don't like", and their soil can harbour harmful Batceria and also provide Nitrates and Phosphates that encourage Algal growth.
Confused?

If you're constantly getting green water then the UV is too weak, and the filter is not doing a good enough job. Constantly adding chemicals is not the answer I'm affraid mate
Aerating the water may help.
Do you get a lot of sludge on the pond base?
Martin