PLEASE NOTE I AM NO EXPERT AND THIS POST IS JUST BASED ON MY PERSONAL KNOWLEDGE,FOR EXPERT ADVISE YOU SHOULD ALWAYS CONSULT A VET WITH FISH EXPERTISE.
Before adding any treatments check your basic water parameters ,ph,kh,nitite,nitrate O2ammonia.
Sera omnipur s Ideally you should never treat without first identifying the exact problem. For people without microscopes,if there are signs of problems(e.g.flicking,skin redness,minor bacterial problems)this is a good broad range treatment.this product contains most of the common koi treatments and some.
Sera omnipur s
Before use
shake the bottle vigorously to ensure that all the different ingredients are mixed thoroughly ensure that you know the pond volume and double check the dosage Do not use with salt above 1/2 ounce per gallon [b Do follow the manufactures instructions. Do increase pond aeration
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There are probably similar effective products on the market, but I am aware of people who have used this with success.
do not leave koi unattended in the first 2 hours of treatment
Tony