In article om,
"Brad Dow" writes:

Is a certain concentration of sodium sulfite critical to the keeping
qualities of developers that use metol as the only reducing agent? To
put the question in context, consider a hydroquinone-free variation on
DK-50:

metol 6g
sodium sulfite 30g
sodium metaborate 10g
postassium bromide 0.5g
water to make 1 liter

With the relatively low sulfite level of 3%, would such a developer be
less stable in storage (in full glass or nalgene bottles) than D76H or
D23, which call for 10% sodium sulfite? If so, what is the minimum
level of sulfite required for good keeping qualities?

I can't answer your question with respect to the developer you mention,
but Patrick Gainer has created some interesting NO-sulfite developers with
excellent keeping qualities. Most of Gainer's developers are
phenidone/ascorbic acid (PC) developers, though. Specifically, PC-Glycol
is made from phenidone and ascorbic acid in glycol with a separate
solution of carbonate. (The two are mixed together at time of use.) PC-TEA
consists of phenidone and ascorbic acid in triethanolamine (TEA), which
acts as both a solvent and an activator. Check
http://www.apug.org/forums/showthread.php?p=255352 for details.

IIRC, metol is soluble in propylene glycol but not in TEA. Thus, you might
be able to cross your DK-50 variant with PC-Glycol to get something
similar to DK-50 with excellent keeping qualities. I made my first batch
of PC-Glycol about a year ago and it's still going strong.

--
Rod Smith,
http://www.rodsbooks.com
Author of books on Linux, FreeBSD, and networking