Hi, I have recenty replastered my pond, and I put the koi back, but for some reason almost all of them died. They where swimming close to the surface of the water imediately after I put them back in. Can this be because of the sealer I used (sicka)

To start somewhere, did you check pond PH before returning Koi?

I have set up a automatic system that monitors the ph etc, but it didnt pick up any problems, it might be that the calibration is out. Didnt double check it.

Because of the sudden death, it sounds like either Chlorine or PH due to the alkalinity of the new plaster.

Did you dechlorinate your water?

Can also be due to stress/shock caused by a big difference in temperature. Did you float the fish first?

Sika products are normally fine. Which one did you use?

Sorry about the lost of your Koi
Hope to see you at our Koi Social event on Sunday 4 October
I would like to get more detail and see pics of your automatic PH system?