Calcium reactor through the Co2 Port

For anyone running a calcium reactor, the Aquarino KH controls the Co2 Port — a power outlet that switches on and off according to what the aquarium needs. It is the equipment's most sophisticated feature and the one that most reduces your manual work.

17.1 The decision, in one sentence

At every measurement, the equipment decides how many minutes the CO2 port stays on until the next one.

	What happens
1 · Measures	The aquarium KH, every hour, 24 hours a day
2 · Decides	Compares it with your target and with what happened over the last 24 hours
3 · Drives	Switches the port on for the calculated time. It switches off by itself

That is 24 decisions a day, 8,760 a year. There is no factory table and no programmed schedule: each unit builds its own model from what it measures in your aquarium. Two aquariums with the same target receive CO2 in different amounts and at different hours, because they consume differently.

17.2 How to connect — pick your scenario

Your reactor	What to plug into the Co2 Port
Without a pH controller	Connect the CO2 solenoid directly to the Co2 Port. The equipment decides, every hour, how long to release CO2 into the reactor.
With a pH controller	Leave the solenoid with your pH controller and connect the peristaltic pump to the Co2 Port. The equipment then releases or cuts the reactor's water flow for the time needed.

The Co2 Port screen explains both wiring scenarios and the ideal operating ranges.

17.3 What it looks at to decide

Two things, and each answers a different question.

What it looks at	The question it answers	Why it helps
Where KH is now	Where are we?	A single reading, compared with the target. It is trustworthy right away, because the reading error is well below the margin — and it is what makes the equipment react quickly to a water change
Where it went over 24 h	Where are we heading?	The difference between KH now and KH 24 hours ago, discounting what the doser added. It is what stops the equipment chasing noise

17.4 Why 24 hours, and not 1 hour

Two reasons, and both belong to the aquarium — not to the equipment.

Reason	Explanation
Noise	Over 1 hour, the natural variation of the reading is larger than the real consumption of that period: measuring the rate in that window would be reading noise dressed as information. Over 24 hours the signal is roughly 14× larger than the noise.
Photoperiod	Corals consume with the lights on and almost nothing in the dark. A 12-hour window overnight would give nearly zero; 12 hours of daylight would give double the average. Over 24 hours the whole day enters once and the effect cancels itself.

17.5 It learns your aquarium's routine

Nobody programs a lighting schedule. The equipment discovers your aquarium's rhythm from how it responds — and the photoperiod curve appears on its own in the data.

Alkalinity consumption by hour of day in a real aquarium, measured by the equipment itself over weeks. Peak at 17:00, minimum at 07:00 — a ratio of 4.8 to 1 between them.

Knowing which hours the aquarium consumes most, the equipment delivers more CO2 in exactly those hours:

Average percentage of time with the port on, by hour of day, in the same aquarium. The distribution is learned, not configured, and refines itself over the days.

17.6 The result: KH swings less

Same aquarium, same total CO2 for the day. Only the hours it is delivered change — and the difference shows in stability:

KH across one day, in the same aquarium and with the same total CO2. Distributed along the routine, the swing falls from 0.35 to 0.19 dKH.

Less swing across the day means less stress for corals: KH spends more time near the target and less time at the extremes.

17.7 Three safety stops

None of them depends on you configuring anything.

Stop	What it does
Daily limit	The equipment never tries to move KH by more than 1 dKH a day. More CO2 means more acid entering the aquarium — reactor effluent leaves at a pH near 6 — and abrupt alkalinity change stresses corals
Automatic cut	If KH climbs well above your target, the port is cut immediately and only returns once KH comes down. It does not wait for the next measurement
Distribution does not add up	The daily routine can reorganise the total, never increase it

17.8 Ideal range and adjusting the bubble counter

Your job here is just one thing: set the reactor's bubble counter so the port works within the recommended range. Do that, and the equipment handles the rest.

Period	Ideal range	Why
During the photoperiod	75% – 90%	With the lights on consumption is higher — the port should run in the upper range
Outside the photoperiod	15% – 30%	With the lights off consumption falls — the port should run in the lower range

17.9 How to read the port percentage

Four readings cover almost everything you will see day to day:

What you see	What it means	What to do
It varies a lot across the day — 10% in the morning, 70% at night	Normal. That is your aquarium's routine, learned	Nothing
It sits at 0% for some hours, with KH above target	Normal. It is correcting downward, on purpose	Nothing
It climbs day after day and KH barely follows	The aquarium started consuming more, or the reactor is losing strength	Watch for 2 to 3 days
It sits at 100% for hours and KH does not rise	The reactor has reached its limit. Software cannot fix this	Check CO2, media and flow

17.10 How to read the graph across days

The shape of the graph tells the story. Three shapes matter:

Shape	What it is	What it means
Wavy and steady	Rises and falls every day in the same pattern, with no long-term trend	This is the healthy state. The equipment found its point and is holding it
A step up, then settles	Climbs over a few days and then stabilises at a higher level	The aquarium started consuming more and the equipment followed. Expected after coral growth or a lighting change
Climbing without stopping, touching 100%	Grows day after day and starts hitting the ceiling often	The reactor is falling behind. Check CO2, media and flow before KH drops

17.11 When the reactor cannot keep up

This is the case where the equipment needs you. It shows the symptom; the cause is physical.

Aquarium KH against the target, day by day: alkalinity settles below target and stops rising.

Percentage of time with the port on over the same period: it climbs to 100% and stays there, day after day.

What to check, in this order:

CO2 cylinder empty or low on pressure;
Calcium media exhausted;
Effluent flow too low;
Reactor undersized for the aquarium's volume.

17.12 What the equipment does not do

Does not	Detail
Does not guess your lighting schedule	It learns the routine from the aquarium's response. If you change the photoperiod it takes a few days to relearn — and relearns on its own
Does not diagnose the reactor	It shows that the port is at maximum and KH is not rising. The conclusion about CO2, media or flow is yours
Does not replace your own reading	The equipment acts on what it measures. If the pH probe is poor, the measurement is poor — and so is the correction. Keep calibration current

17.13 Correction mode and default status

Setting	What it does
Correction mode	Enables or disables automatic control of the Co2 Port. It ships Disabled
Default status	Sets whether the port stays on or off when automatic control is disabled, or when the equipment has no basis to decide — during filling, emptying, or right after startup