To replenish LPD:
First fresh kit:
1. Mix a gallon kit as stock solution, as described on the package. Use distilled water, or at least boiled water.
2. Take 1/3 and mix it 1:2 for 1 gallon working solution.
3. The remaining 2/3 and mix it 2:1 as replenisher.
Add 300ml per qty 30 8x10 prints, and top off the working solution after each printing session as necessary with replenisher.
When you run out of replenisher, you mix your second gallon kit:
1. Instead of mixing the 1/3 of stock with water, mix it with the old developer.
2. Mix the remaining 2/3 the same way as the first time around, at 2:1 as replenisher.
It's a great way to use it, and prints with wonderful range and tones.