After having two stalled sugar washes due to low PH, I did some reading here and there.
The remedy was to use calcium carbonate....in the form of oyster shells...or shell grit.
I prepared a standard sugar wash (dextrose) with the usual addition of nutrient (DAP) and a bit of out-of-date bakers yeast.
BUT....This time I added 2 oyster shells that I previously sterilized by steaming, steam baking at 250 deg C and steaming again just to be sure.
Drilled a small hole in each one and tied them together with a length of cotton thread.
Attached the other end of the cotton thread to a cork from a bottle of cheapo champers.
The thread was long enough so that the cork floated on the surface of the wash for easy retrieval. (The cork was not big enough to support the shells in suspension)
Next time I will try a cork sanding block so that the shells are suspended in the wash and not sitting on the bottom.
After 7 days I checked the SG and it was 0.990.
NO STALLING (I was happy)
Pulled out the shells and....see photo
They did their job.