These vessels have been specifically designed for use in the balling  method of supplementing a marine aquarium with Calcium, Magnesium and Alkalinity with the use of a dosing pump. However they are versatile enough to allow you to dose any liquid product from them in to your aquarium. The pipes are the correct size so ordinary aquarium air line can be pushed on to provide a secure grip straight from your dosing pump (we recommend silicone airline), or you can use RO pipe. They give a professional look you don’t get from plastic bottles and are very user friendly as the top just lifts off easily for topping up. The suction from the dosing pump doesn’t allow any liquid to drip out when you remove the pipe complete with the lid. Perfect for people who are limited with space inside their cabinets. Each vessel is easily cleaned and rinsed out. Dimensions (cm) – 11 x 17 x 11