The TrueDPD reagent bottle comes in 3 sizes, 4, 8 and 16 ounces. The 4 oz size is recommended when using the powder which will require the most frequent refills. The larger sizes can be used with the liquid reagent as it doesn't darken over time.
Include the selected bottle size with the tube. The 4 oz bottle is included with the TrueDPD. When using a different bottle size, visit the TrueDPD menu in the controller and select the bottle size.
When using the 8 oz bottle, use 2 scoops if using the powder reagent. When using the 16 oz bottle, use 4 scoops if using the powder reagent.