Koi filter is cleaned but water is still dirty and is full of diseases and virus which are killing your Koi fishes,
Dirty water causes Virus & fungus diseases.
Symptoms-Koi swimming in a spiral fashion as virus has attacked the brain. Healthy & Active fishes, odourless fish pond, clear water, No more algae.
Use CWKE 1 pack (100gm) weekly for a 5,000L water fish pond.
Stop death/Disease/ Viruses.
For healthy fish, clean & clear water.
Use Nano Anti-Virus for prevention(monthly) 250ml/500ml water fish pond.
For treatment 1L every week for 500L fish pond