I have this unit on my black and grey tank vents and it is wonderful for dispersing odors. Many times the odor you smell is actually drawn in from the roof because using a fan can change the pressure and draw air from the roof down.
Using any acceptable method of rinsing and flushing your black tank will keep odors down. All those mentioned are effective. I'm a bit skeptical of the ice method because hot water cleans better than cold but people say they have success so trying it does not hurt. Also remember to use lots of water with each flush. Harder to do if you are boondocking.
The key is to flush as often as practical and clean it regularly. Soon the odor is a thing of the past.
I do all my own stunts
03 Dolphin LX 6355, Workhorse W22, 8.1 vortec, 04 CR-V, Blue Ox, Brake Pro----Norm, Barb and
Doc(He's a PhD)