Looking towards the top left hand corner you can see the installation of a pressurised canister filter in the pond. Seeing as both skimmer and waterfall are set in place, if you can access the pipe that sends the water from the pump to the fall, you'll have the possibility of adding additional filtration to get rid of your green water problem (as a result of increasing the area for good bacteria which consume nutrients that cause the green water).

I've been through green water, and I've looked at many solutions. Because koi grow really large and produce plenty of poop, increasing biofiltration will help in the future and beyond. Non biological filter approaches often do not work, such as huge water changes, algae cure chemicals (which kill the algae, but as a result increase the organic load in the pond because you've killed the algae - and things that decompose can increase ammonia), barley straw etc. Often most are time consuming, pointless wastes of money that should have been directed to building a larger biofilter.

Have fun!

Regards,

Aquaman

Nearly all of the bioballs in existence are made from plastic. I've supplied a photo of them here:

The water is showered down from the top and exits the bottom. I believe the sidepipe in this picture is used for purging and is not included when building a similar filter for a pond.

The bioballs are therefore better used after any prefiltration because when the bioballs are fed with pre-cleaned water (meaning some sponge has already removed large bits of leaves etc and is only passing pond water through) they will work much more effectively.

If used before the filters, you will find the need to clean them regularly.

Because plastic bioballs take some time (4-8 weeks in my case,as well as others) washing the bioballs will clear any good biological film that has grown on the bioballs. Therefore as before, place them in an area where you are unlikely to remove them at all for cleaning (which you shouldn't do at all).

If you wish to submerge the bioballs I believe they won't work as well as they would in a wet/dry filter (or in large pond filtration applications "trickle towers") because as I have tried, when I first cleaned the bioballs (before use) the way the water collided down through the bioballs it created a lot of airation in between the bioball media (which is good for cultivating the positive bacteria (in this case aerobic bacteria). I would more likely try and source a different biomedia best used in a submerged application like ceramic rings.

In the alternative, you could always look into constructing a new filtration system to be situated in the open area, and have a new submersible solids handling pump feed that filter system instead. You would therefore have two filter systems on the pond, and you wouldn't need to cut into the old filtration system to fit additional filters. You could make the second filtration system be based on "trickle towers" (running two barrels/containers) with one as a settlement tank, and the other as a trickle tower.

Regards,

Aquaman

1. How big are those 2 bio-filters and what is the size of the lids - ie: what is the largest thing you can push into them easily and are you only using a layer of foam to act as mechanical filtration? I am concerned that you are passing soup through into your bio filters.

1. Check your water for all your other parameters regulary until you get this sorted - ie: Ammonia, Nitrite, Nitrate etc - if you detect these do partial water changes whilst you fix your filtration problem.
2. Add additional oxygen
3. Buy the B504 - great stuff (we have to import it here, so it ends up costing and arm and a leg - but worthwhile nonetheless!)
4. Fix your filters.......