LIGHTING & CO₂

Bubble Counter

Clear chamber that turns CO₂ flow into a countable bubbles-per-second rate.

Planting stage Lighting

Unplug before servicingHands out of the water firstDrip loop on every cableTest before you dose30 ppm CO₂ ceilingCycle before stocking

Lighting

Technical line drawing of Bubble Counter

Specification
Type	In-line or regulator-mounted
Fill	Water or mineral oil
Rate range	0.5–10 bubbles/s
Fittings	4/6 mm hose
Body	Acrylic or glass
Check valve	Built in on most units

Technical parameters
Typical 60 cm tank	1–2 bubbles/s
Typical 90 cm tank	2–3 bubbles/s
Typical 120 cm tank	3–5 bubbles/s
Count window	30 seconds × 2
Fill top-up	Weekly if water-filled
Oil fill life	6–12 months

A bubble counter is a small transparent chamber partly filled with water, fitted between the regulator and the diffuser. Gas enters at the bottom and escapes through a tube, and each bubble that rises is a discrete, countable unit of flow.

Its value is repeatability. "Bubbles per second" is not a scientific measurement — bubble size varies with the counter and the pressure — but it is stable on one system, which means it is the reference you use when you adjust the needle valve and want to know whether you moved it or not.

Counters are usually filled with water, but mineral oil is a better choice in practice: it does not evaporate, so the level does not need topping up, and it produces more consistent bubble size. Some counters are integrated into the regulator body; others are separate in-line units.

Safety and welfare

A bubble counter is not a substitute for a drop checker. Bubble rate tells you what you are injecting; the drop checker tells you what is actually dissolved.
Fit a check valve. Without one, water can siphon back into the regulator and destroy it.
Do not over-tighten acrylic fittings. They crack at the thread and the leak is invisible until the cylinder empties overnight.

Using it well

Count for a full 30 seconds and double it. Ten-second counts are too short to be accurate.

Mineral oil does not evaporate, so the rate stays comparable week to week. Water-filled counters drift as the level falls.

Write your working rate on a label on the cylinder. After a refill or a clean, you can get back to a known state in seconds.

Part of

CO₂ regulatorCO₂ diffuserDrop checker

Worth knowingA measuring aid only. The drop checker remains the authority on dissolved CO₂.

Note. Parameters are conventional ranges across the category, not the claim of any one manufacturer. Nothing on this page is for sale and no outcome for any plant or animal is guaranteed. Simulator output elsewhere on this site is a simplified model, not a measurement — confirm everything with a test kit and the equipment's own instructions.

Bubble Counter

Using it well

Part of

Works alongside