I can assume the fish was purchased from Tom Tse? Well, back to the thread...The scaling is too dark for me, and living here in the Bay Area the scaling will either get really dark or shimi'ed out...JMHO...
first of all let me say that I'm delighted to see you getting involved with the breed. They are not the easiest to keep at their peak and need special water so i think you'll learn a lot from this involvement koi education wise.
I anticipate that the red will over run it next year into the body where it isn't suppose to be. And i do agree that this guy is pretty dark already in the asagi-han blue area. It may be something other than Narumi.
BUT
keep it off color food and try and keep you GH as close to 125-130 as is reasonable. The 200 area would be better suited for go-sanke. If you subscribe to KB already you might want to re-read issue 8 or get your hands on that copy to understand more about the breed.
Thanks for posting the photo and good luck with your new charge....I hope you prove us all wrong!
I too would be concerned as to what your other parameters are as a zero Gh doesn't seem right? Are you sure your test kit is fresh and accurate. Could something have happened to compromise it's readings?
Young koi ( and good bacteria ) both draw minerals for life and growth from the water....
My KH ranges from zero to 2 drops. PH is around 7.7-7.8. My test kid did not have an expiration date. I got them a few months ago. When I add a little bit of bs the KH did move to a high range 4 drops or more. So I would think the kit is good. What do you add to get the GH to move higher? Thanks