3 observations as an xtol user who gets 6 months from it no problems.
1: I use a filter jug and never have the particle issue, it's cheaper than buying water
2: I use screw top wine bottles (seem to have an endless natural supply of them!) with saran wrap and the they are fine... not brown but still dark.
3: I started getting better longeivity when I stored the chemicals in the hot press , this applies especially to winter as it's probably the most temperature consistent place in the house and also when I go to develop the base temperature is always around 18C so it doesn't take much time to get everything up to 20C.