Koi dying suddenly - Old bog water to blame?

[Jhn]

Save the money on the beneficial bacteria, as at best it is useless, as the bacteria is already present in your pond, and will expand to Consume it’s available food source be it ammonia, nitrites, etc. Besides it won’t do much for the algae bloom, agree with everyone else, patience it will clear on its own. Also, as was said numerous times consider leaving the bog running year round from now on.

 

[SaltLakeCity]

Thanks. I will be changing the bog a bit to allow year-round use - there is a low side that is prone to losing water. We have saved 3 of our 8 koi and are starting over with a full water refresh as whatever is killing the fish from the bog seems to still be present after a 50% water change - we put one koi back in and it died. The bright side is that my wife now knows all the ins and outs of the pond and is very interested in participating going forward. Anyone selling koi in the Salt Lake area?

 

[GBBUDD]

I strongly suggest posting some pictures. It would be the first time it showed ahhhh there's your problem

 

[mrsclem]

Make sure if you are using tap water for water changes to treat for chlorine and chloramines. Also, check the Ph of your tap water.