After snip­­ping off the top of the external hose connector on the new black caps on the A B & C Additives by red sea, the cap can be connected to a dosing pump with standard-sized silicone tubing. A 2nd, larger diameter tube (not included with the supplements) needs to be connected to the internal hose connector of the cap to maintain a steady flow of supplement until the bottle is empty.

This is a twin pack of the inner large diameter tubes which fits the 1000ml and can be cut down for the smaller 500ml bottles.