Another alternative to premade stop baths - A teaspoon of citric acid crystals in a litre of water mixed just before it is needed. Citric acid can be purchased at most chemists and is also found under the baking or brewing section in many supermarkets.
ILFOSOL 3 does NOT oxidise quickly and we have no issue with any recent batch or any other previous batch come to that.
ILFOSOL 3 has indeed improved oxidising performance than ILFOSOL 2 and ALL develops once opened can ( and do ) deteriorate, but lots of good info posted on APUG on how to properly keep part used chemicals.
Simon ILFORD Photo / HARMAN technology Limited :
I like Ilfosol 3, and as Simon says, it is better keeping than Ilfosol S. HC-110 is good also. I don't think you can go wrong with either. As for stop - I don't use stop bath for films, just water wash for 30-45 seconds. If I do use it, then it's one-shot. I don't think it matters what brand of fixer you use. They all seem to work fine, and work the same way. The big thing is don't over use it, as stated above several times. I use HypoCheck, and only use it for 3/4-7/8 the recommended number of films. The problem is, you don't know it didn't do a good job until too late when the film turns yellow and becomes more dense from the left over silver. Fresh chemicals are more important to me than brands. Just IMHO.