Bleach may harm the valve seals. I personally have taken a liking to Odoban that is available from Home Depot and Sams Club. I got tired of Eucalyptus and am now using lavender or their lemon scent.
Odoban is incredible and it what I use on pet odors in my basement....my dogs are spoiled and when it is snowing or raining outside, they will urinate on the unfinished concrete floor. This stuff works awesome in disinfecting and elminating ANY odor!
Another example, our new "used" fifth wheel had mouse infestation in the heating system. The heater and the ducting were full or urine and the solid waste product of the animal's digestive tract. I removed the heater and sprayed and rinsed the heater with odoban and then flooded the duct work with odoban and used a wet dry vac to suck it out of the low point and my heating system smells better than new!
This stuff works and a little splash will take care of grey water and black water smells. I spray a bit in the toilet bowl too which helps greatly.
Amazon has favorable reviews for this product: http://www.amazon.com/Eliminator-Con.../dp/B000ZOQ9HY
It is strong so if you use it for other things, make sure you dilute it. The scent can be overpowering but will dissaipiate after a couple of days.