Shelf life of 0.04% bromothymol blue for residue glassware test

Quality Control
1

Please, anyone know shelf life of 0.04% bromothymol blue indicator solution for residue glassware testing.
PS. self prepared in laboratory.

2

shelf life of 0.04% bromothymol blue indicator solution is 3 year.

3

Thank you for your help. Could you tell me about reference data?