Dilution Rate
The goal in determining your dilution rate is to find the most you can dilute the product and still have the desired feel of the foam. As a general guideline, you should be able to dilute your normal liquid soap by 3 - 6 times.
Start with 1 part soap and 3 parts water, and add additional water (if you want) until the soap foam thins a little bit. That will tell you how much of that particular type of soap to use.
Other Additives
Inside the pump of the Foamy Pump Bottle is a little mesh screen that mixes the soap with air to produce the foam. The holes are microscopic (79 microns - very tiny!), and can easily get clogged.
Airspray, Inc. does not recommend the addition of any solid particle, even if it is under 79 microns, as solid particles tend to clump together, making them too big to pass through the mesh. Micas, pigments and any type of glitter are too big to work in the foamy pump bottles.
If you want to color your liquid soap, use a cosmetically approved dye. These work similarly to food coloring and do not contain any solid particles big enough to clog the mesh inside the pump.
Note: Some thickeners can create "clumps" of soap that are big enough to clog the screen. As noted above, melted down bar soap is likely to do this.
Usage and Care
The pumps are not designed to be used under running water. Use in the shower is not recommended and the bottles should not be placed or washed under running water. Doing so can allow water to seep down the neck and get into the air chamber located beneath the pump.
Do not overfill the bottles. Actually measure out the right amount of liquid for the bottle size - you'll see that it doesn't actually fill to the very top of the bottle. This is to prevent liquid from getting into the air chamber.
Bottles can be refilled and used again and again. The manufacturer has tested the bottle/pump design and found it works for up to 12,000 pumps per unit.
Troubleshooting
It the pump stops working properly, check the following:
Is the soap too thick?
To work in the foam pump bottles the liquid should be water-thin. If it is too thick, the pump won't work properly and/or can be permanently damaged. Increase the dilution rate or use a different soap.
Is there liquid in the air chamber?
You should see it inside the chamber below the pump. If so, turn it upside down and pump a few times which should get the water out of the air chamber. If that doesn't work (and if you are brave) take the pump apart, clean it completely, dry thoroughly and reassemble.
Has there liquid in the air chamber for a while?
If so, clean as above. However, if the soap has had time to degrade the silicone in the pump, it may not regain the original amount "spring" back up.
Is the screen clogged?
Empty the container, clean the screen and flush with water (it won't foam). Use a different liquid soap without particles in it that can clog the screen.