Two Simplicity 5 Liter containers & Neptune DDR DOS Dual Reservoir sensor built in. The total volume of both is 10 liters total for both containers. When plugged into the link cable port of a neptune apex the DDR screen will come up so you can change the holding amount to 5 Liters and the sensor that comes with can alert you that the volume of your material you are dosing with is low. This is a Simplicity container that i drilled out the holder of to mount a sensor that a third party manufactured but works just like a Neptune DDR just bigger and less money.

The Simplicity 5L Modular Dosing Container allows you to easily connect multiple units in order to suit your unique doing needs. Its clear, acrylic body has easy-to-read graduated measurements in both liters and fluid ounces so you can quickly monitor your remaining solution. Being acrylic, it’s impervious to chemicals used in reef keeping, including 2- or 3-part, RODI for top off, nutrient/bacterial supplements or lanthanum salts. The container also features a snug-fitting lid that will protect your solutions without creating a vacuum, strong PVC hose connectors will safely keep your dosing tubing in place