The standard three supplement regiment of a phosphorus free calcium, a calcium with D3 and a multivitamin without D3 has been used successfully for many years. I will quote the version from the resources section of the forum "Feeder insects should be lightly dusted with powdered supplement before being fed to your chameleon. As a montane species (native to higher altitudes) Jackson's have decreased supplementation requirements compared to tropical species due to metabolism differences. Use calcium (without D3 or phosphorus) twice a week, a multivitamin once a month, and calcium with D3 once a month."
I personally use a two supplement regiment of phosphorus and D3 free calcium mixed with powdered bee pollen and Repashy Calcium Plus LoD, the one with the Jackson's on the label. I don't know if the bee pollen is of any value but it seems harmless and probably at least provides dietary fiber. I consider it optional. My schedule is used with a T5 linear fixture with a 5.0 or 6% light. Monday, Wednesday and Friday I dust with phoshorus free calcium mixed with bee pollen 2:1 or 3:1. Twice a month I substitute Repashy Calcium plus LoD for a Monday's calcium. This way they get 2-3 doses of calcium per week and two doses of multi vitamin with a little D3 per month. Clearly the days of the week don't matter as long as they are every other and not more than three per week. When I keep my chameleons outdoors I modify the schedule to only one dose per month of the Repashy LoD and I'm only giving it for the multivitamins it provides.
Arcadia makes the third supplement combo. I have never used it and can not give you any real insight. There was a time when it was more difficult to source in the US but it seems that has been resolved.
