For leopard geckos I suggest using Zoo Med's supplements like this:
1. Monday -
Repti-Calcium with D3 on all crickets
2. Thursday -
Repti-Calcium with D3 on all crickets
3.
Reptivite with D3/A acetate adjusted for your leo's weight: Spread out the Reptivite with D3 dusted crickets over the course of a week.
***Current directions (16 May 2013) on Zoo Med's Reptivite with/without D3/A acetate
"Directions for Insectivores: Place crickets in a plastic bag with a small amount of Reptivite w/d3 and shake to "dust" crickets with the powder. Feed approximately 12 dusted crickets per week for every 2.5 ounces (71 grams) of body weight."
So if your leo weighs 24 grams, the recommendation would be only 4 lightly dusted crickets per week with Reptivite with D3. Baby leopard geckos weigh much less, so be sure to adjust the dosage accordingly!
Do not exceed the recommended amount of Reptivite per body weight. One real problem in recommending exactly what to do is the size of the crickets fed.
Zoo Med's customer service (USA): 888-496-6633
Beyond formal gutloading right prior to feeding off and dusting, feed your feeders a nutritious diet 24/7. Feeding off crickets whose entire body is healthy (and not only their guts) is very important!
If you use a formal gutload such as T-Rex Calcium Plus Food for Crickets or Repashy's SuperLoad as well as feed a nutritious diet to your crickets 24/7, chances are that you will need to tweak the above "schedule" to prevent oversupplementing.
http://www.geckosunlimited.com/comm...-feeding-issues/68574-cricket-guidelines.html