Some context: D23 was designed as a substitute for D-76, with superiour characteristics which would be suitable for replenished tanks in commercial labs. This was circa 1940. As simple as it SEEMS, D-23 is an extremely elegant developer.
Kodak specified DK-25R, and instructed that one replenish the developer with 6 gallons of replenisher for every 1000 rolls processed. Further, Kodak specified that the developer be replaced after 100 rolls per gallon ( 8000 sq. inches ) have been processed.
I know that upon ocassion, this instruction was overlooked. Replenishment succeeds when there is a high volume of film being processed regularly. In daily use, the stuff never really goes bad, but at some point the balance can't be maintained. Like keeping a color processor happy, running a couple rolls through the works in a week isn't really a happy way to go.
DK-25 R looks like this:
Water 750 ml
Metol 10 grams
Sulfite 100 grams
Balanced Alkali 20 grams
cold water to make 1 liter
This was from Kodak's Gospel, 1951.
With any luck, Mr. Troop will weigh in on this matter !
df