Magamp D fertilizer

[badatusernames]

I was just watching this video:

He indicates a couple of interesting things - firstly, that older chojubai shouldn't be fertilized much, and secondly, that Magamp-D should be used when you do fertilize.

Magamp-D is the same as Magamp-K, but D has pesticide in it.

I found Magamp-K here:

https://www.etsy.com/listing/931246474/2-lb-magamp-k-fertilizerslow-release?ga_order=most_relevant&ga_search_type=all&ga_view_type=gallery&ga_search_query=magamp+k&ref=sr_gallery-1-1&sts=1&content_source=4af78a3fd49d60497c7e409c4fe61166174d16d9%253A931246474&search_preloaded_img=1&organic_search_click=1

I was curious if anyone had experience with it?