it is easy to see and is well circulated by water [e.g. on the side pane
of the aquarium, using the suction cups (1.9)].
Operation
First adjust the pressure at the pressure reducer (1.7) to approx.
1.5 bars (21.75 psi.). Then open the fine needle valve to about 60 bub-
bles/min. The number of bubbles is easily visible in the cone shaped
lower part (3.1) of the pressure diffuser. The bubbles cleanly escape
from the tip near the bottom and rise towards the ceramic disc (3.2)
which finely disperses the bubbles as they are pressed through.
The CO
2
amount your aquarium needs depends on the growth of
the plants, which is also influenced by other factors such as light
quality and light amount. We generally recommend applying an
amount of 60 – 100 bubbles/min. for a well-planted aquarium con-
taining 200 – 300 liters (53 – 79 US gal.).
Monitor the CO
2
concentration with the
sera CO
2
long-term indica-
tor
and adjust the CO
2
supply towards higher or smaller amounts ac-
cording to the result. The energy binding photosynthesis process –
and, correspondingly, the CO
2
fixation – stops as soon as the lights
are turned off in the evening. Continuous CO
2
addition during dark-
ness would only cause pH lowering as it reacts with water to form
carbonic acid. This will affect fish breath. The CO
2
supply can be easily
interrupted by a
sera CO
2
solenoid valve
and a simple electric timer
(fig. 4).
13
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