Until TechnoFresh® came along, the only method of controlling laundry odor and rashes caused by the growth of mold, mildew, and bacteria slime in the washing machine were monthly shock clean treatments of various kinds (Tide, Affresh, Smelly Washer, etc.).
These shock clean treatments often fail to remove all the biofilm growth and detergent build up in the machine.
This failure to completely clean the machine allows biofilm growth and odor to come back quickly after a shock treatment.
The growth return is exponential through time.
The shock treatment may (seem to) clean the machine.
For about 7- 10 days or so, the smell is gone from the machine and laundry.
For the next 7-10 days or so, the laundry starts to smell a little.
The next 7-10 days the mold, mildew and bacteria slime are back and the machine smells and the laundry is back to to smelling like mildew.
A week or so after that you get knocked back on your butt when you open the door.
(No, really, I once was hit with a blast so foul I jumped back by reflex and almost crushed the dog. That is when the need for something that actually worked to control odor occurred to me)
The problem is that the growth explodes in the last part of the month so it can be difficult to time the next shock treatment.
How infested the machine and laundry get through the month depends on how well you time the shock treatments.
Even if you time things well, you still are getting some mold and mildew residue on clothes, sheets and diapers all through the month.
Some loads have more mold and fungus residue on them than other loads.
That is why the problem seems to come and go in a random manner for no reason. Random rashes and itching are very common.
You can run shock treatments every week or two to try to stay ahead of the growth curve.
But, that is a lot of trouble and can get expensive.
And, you have to remember to do it.