Sodium Bisulfate Stop

I make my stop out of 26 grams of Sodium Bisulfate in 2 gals. of water. That comes out to about 3/4 full of a 35mm canister. Works very well for paper and film. Lasts a long time. As an indicator for exhaustion I put in 20 drops of Phenol Red. This is the stuff you use to check the Ph in a pool or hot tub. Both of these can be bought anywhere you buy pool supplies. Very cheap at Wal-Mart. The indicator turns the stop light yellow when still good and pale violet when exhausted.

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