Missing part

[Shrimplicity]

Hi guys! What part am I missing here?

[Urban Aquaria]

Thats the needle valve to attach the bubble counter to. I don't see a solenoid so that is a manual regulator.

You can also replace that part with a solenoid regulator with needle valve too. Automate the injection schedule and timing.

Here is a photo of a system fitted with solenoid regulator (you can see the needle valve screwed/attached to the bubble counter):



Photo from Google Images.

[Shrimplicity]

Thanks ua!