WayneC,
Sorry, but you are overstocked.
If your pond volume is 15 000 liters, each fish only has a 517, 24 liter’s area!
The Ultra-Zap Bio filter in the photo, according to their calculation, is suitable to a pond volume of 12 000 liters. I found that this is best for a pond of 10 000lt!
In view of this, the bio filter is too small for the capacity regarding the ratio between the water volume of your pond and the amount of fish it is holding. This will cause the sand filter to “block” quicker and you have to back wash it more frequently. Remember a three-bag sand filter could be adequate regarding a swimming pool with a bigger water capacity, but only with the help on chemicals. Fish produce an ongoing waste into the water.
The best is to open the sand filter and turn the sand “by hand” while it is back washed, if you fail to do this, the sludge at the bottom of the sand filter becomes “hard,” and this will influence the working of the filter, and will create a breeding ground for “Bad” bacterium as well.
If the water quality is bad, it is harmful to Koi, and it could cause bacterial disease and stress.
Stress can also trigger a parasite outbreak.
At this period of time you may have had no problem at all with your pond, but you are sitting on a time bomb! I had a similar set-up and overstocked as well, sadly I lost 37 Koi in a week after an Aeromonas and Pseudomonas bacterium infection of my pond.
Maybe you should think about making your filter system bigger.
Home 
Calendar
