Reserve module seen from three-quarter view, outlet and connecting tube

Diagram of the module and its connections, manufacturer's instructions

Illustrated parts diagram of the module, piece by piece

Illustrated assembly and connection steps

Network filling and level-setting diagram

Constant-level water reservoir for growing pots, 45 L

Name: Constant-level water reservoir for growing pots, 45 L
Brand: Terra Aquatica
SKU: TA-CM-CTRL
Price: 153.0 USD
Availability: InStock

$153.00

$51.00 × 3 with no fees Klarna.

The CultiMate Controller is the module that turns several standalone CultiMate pots into a battery linked to a shared reservoir. A float valve keeps the level constant, and an air pump circulates the solution.

It consists of a 45 L reservoir, a 15 L controller pot, the valve, the air pump and the fittings.

Ref. TA-CM-CTRL·Soilless growing accessory

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The summary

What it is: a 45 L reservoir and a 15 L controller pot which, through a float valve, keep the same level of solution in all the connected pots.
What it is for: you fill a single tank instead of four, and your plants all receive the same solution at the same level.
What is supplied: the two tanks, the solid lid, the float valve, the 1.8 W air pump and all the connecting fittings.
What it connects to: the 15 L and 45 L grow pots from the same range, using fittings with a one-inch and a half-inch thread.
What you choose to go with it: the pots themselves, the grow medium, the nutrient solution and a way of reading the pH.
Dimensions: a single parcel of approximately 47 x 47 x 43 cm, weighing 5.18 kg empty.

A 45 L reservoir and a float valve, to keep several pots at the same level

Four grow pots means four reservoirs to fill, four pH readings to take and four solutions that each change in their own way. The CultiMate Controller removes that work, because the pots are connected to a single reserve and a valve keeps the same level in all of them. You prepare only one solution and measure only one pH.

🛟 The float valve

The principle is that of a drinking trough or a toilet cistern, applied to growing. The 45 L reserve sits above the 15 L controller pot. When the level drops in the network, a float follows the movement and opens the valve, then the reserve empties by gravity until the level returns to its height and the float closes the valve. There is no electronics, no sensor, no adjustment, just a mechanical part that uses no power.

🔁 What a shared water level changes

On a set of four pots, the difference is clear: instead of four top-ups a week, you fill a single reservoir, and your four plants all receive the same thing. It is also a safeguard, because a more exposed pot, whose solution evaporates faster than the others, no longer ends up dry without you noticing. The controller's level tube shows you the state of the whole network at a glance. As for the materials, the reservoir and the controller pot are rotomoulded in France from opaque recycled polyethylene, which keeps the solution in the shade even when placed in full daylight, and the air pump uses 0.04 kWh per day of continuous running, an annual cost of just a few euros.

The reserve

It holds 45 L, with a solid lid. It is the water reserve that feeds the whole network, and it determines your autonomy.

The controller

It is a 15 L pot drilled in two places, which takes the float valve and links up with the other grow pots in the network.

The valve

This mechanical float valve opens and closes by itself, with no power supply or battery.

The pump

A 1.8 W air pump, the same as on the 15 and 45 L pots, provides circulation throughout the network.

The pots this module controls

This module manages level and circulation, and it is the 15 or 45 L pots that carry the plants. If you are starting from scratch, the four-pot kit brings the two together in a single box. Also plan for a pH test, since the value is now read at a single point and it governs the whole network. A pH drift that went unnoticed on a single pot now affects every plant in the network at once, which makes measuring all the more worthwhile.

Rinse, cover and renew the solution in the system

Do not pour in clay pebbles that have not been rinsed: the dust gets into the system and settles on the valve seat, which then fails to close properly. Do not leave the reservoir in full sun without its lid, as algae take hold in nutrient-rich, well-lit water before spreading to every pot. Do not simply top up for evaporation for months on end without ever changing the solution, and renew it completely every 2 to 3 weeks, rinsing the float while you are at it.

🧪 One solution, one pH

This is the corollary of the shared level, since all the plants in the network share the same nutrient solution. You save a considerable amount of time, and you accept one constraint: you cannot give one plant a growth formula and its neighbour a flowering formula. The network is run as a single crop, which encourages you to grow plants of the same species, or at least the same stage, in it. Nothing stops you keeping a separate pot alongside the network for a staggered crop. The pH range remains 5.8 to 6.2, measured in the controller pot, and our article on pH regulation sets out the method in detail.

🚰 Preparing the solution for the network

You prepare once what the pots will share. The grow medium comes first, with clay pebbles of 8 to 20 mm grade rinsed until the water runs clear, at roughly 20 L per grow chamber of a 45 L pot. The nutrient solution comes next, growth, trace elements and bloom, dosed for the total volume of the network and not for a single pot. Finally, the pH is adjusted, read in the control pot and corrected to between 5.8 and 6.2, since this is the only measurement you will take for the whole system.

📐 Assembling the network

The set-up needs thinking through before the first litre of water goes in, because a communicating-vessels network allows no approximation on levels. Place all the pots on one perfectly horizontal surface, checked with a spirit level in both directions, otherwise the lowest pot will fill at the expense of the others. Then place the reservoir higher than the controller, since the transfer is by gravity, and keep the connections as short and as straight as possible. Finally, allow clear access to the float, which you will need to rinse regularly, rather than leaving it wedged behind three pots full of tomatoes. The pots are linked by 15 x 17.5 mm tubes; to get round a corner without crushing the bore, the original 16 mm ribbed elbows and joints are ordered in packs of 5.

🪣 Real-world autonomy

The 45 litres of the reservoir give a running time that depends entirely on what your plants drink, and this figure matters when you are going away for the weekend. Four pots holding plants in full production easily consume several litres a day in summer, which brings the running time down to a little under a week in those conditions, compared with several weeks for herbs in the shoulder season. Measure your actual consumption over 3 days before relying on it, noting the drop in level in the reservoir. It is the only way to arrive at a figure that holds for your setup, your exposure and your plants.

Technical specifications

The essentials

Function: Constant-level reservoirKeeps the same level of solution in all the connected pots, using a mechanical float valve.
Reserve volume: 45 L45 L reservoir with a solid lid, also available as a spare part.
Monitor pot: 15 LDrilled with a one-inch hole and a half-inch hole, it takes the valve.
Regulation: Float valveA mechanical part, with no electronics or power supply. It keeps working during a power cut.
Compatibility: 15 and 45 L potsFittings with a one-inch and a half-inch thread, like those on pots from the same range.
Material: Recycled polyethyleneRotationally moulded in France, opaque, which keeps the solution in the shade.

Pump and connection

Pump included: Air pump, 1.8 WThe same as on the 15 and 45 L pots in the range, and replaceable on its own.
Air flow: 1.3 L/minConstant airflow, day and night.
Consumption: 0.04 kWh per daySimple calculation: 1.8 W for 24 h.
Taps and fittings supplied: CompleteSplitter tee, barbed connector, 90-degree elbow, black and clear tubing cut to length, seals.
Level tube: SuppliedWith its retaining clip. It gives the level of the whole system, not that of one particular pot.
Feed: 220 to 240 VStandard mains socket, for the air pump only. The valve itself draws no power.

Dimensions and delivery

Footprint: approximately 47 x 47 x 43 cmDimensions of the complete package. Once assembled, the network takes up more space, as the pots are spread around it.
Empty weight: 5.18 kg
Parcel: 1 parcelBulky but light, at around 5 kg.
Reservoir lid: Solid and opaqueLeave it in place outdoors: it stops rain from diluting the solution in the whole system.

To budget for separately

Grow pots: 15 or 45 L pots
Grow medium: Clay pebbles 8 to 20 mmAround 20 L per growing chamber of a 45 L pot, to be rinsed before use.
Nutrient solution: Complete nutrition in 3 bottles
pH reading: Drop test or meterA single reading is enough for the whole network, taken in the controller pot.

12 further specifications are available in the detailed view.

In the box

1 reserve reservoir of 45 L with its solid lid.
1 controller reservoir of 15 L, drilled with a one-inch hole and a half-inch hole.
1 mechanical float valve.
1 air pump of 1.8 W with its one-metre clear tube.
The fittings: 1 distribution tee, 1 connector tee, 1 barbed joiner, 1 90-degree elbow and 3 tubes cut to length.
1 level tube and its clip, 1 one-inch sealing washer, 1 half-inch seal and 1 adapter seal.

Dimensions, weights and parts taken from the packing list, the parts catalogue and the manufacturer's instructions, on 10/09/2026 and 08/10/2026.

This module on its own, or the complete four-pot kit?

Two ways of reaching the same result: a single filling point for several plants.

The reservoir is available on its own, or supplied with its four pots If your pots are already in place, the module simply adds on to them. If you are starting from scratch and four plants are enough, the kit fits in a single box.

	Grow pots included	Reserve and level regulation	Air pump included	Added to pots already in place	Any number of pots	Reserve volume (L)	Price
Recommended Constant-level water reservoir for growing pots, 45 LYour choice	No	Yes	Yes	Yes	Yes	45 L	$153.00
Hydroponic kit with 4 pots connected to aYour choice	Yes	Yes	Yes	No	No	45 L	$481.00

Constant-level water reservoir for growing pots, 45 LRecommended

What you receive

Grow pots includedNo

Reserve and level regulationYes

Air pump includedYes

Flexibility

Added to pots already in placeYes

Any number of potsYes

Reserve volume (L)45 L

Hydroponic kit with 4 pots connected to a

What you receive

Grow pots includedYes

Reserve and level regulationYes

Air pump includedYes

Flexibility

Added to pots already in placeNo

Any number of potsNo

Reserve volume (L)45 L

Contents and specifications taken from the two product pages on 08/10/2026.

Documents & manuals

Manufacturer's page, CultiMate range

Introduction to the Terra Aquatica range, in French.

LIEN

Download

Manufacturer's page, four-pot system

Description of the four-connected-pot system and its management module, in English.

LIEN

Download

Estimate your
delivery time

A single parcel of approximately 47 x 47 x 43 cm weighing 5.2 kg. The format is bulky but light; it will not fit through smaller collection points. Exact shipping costs and final delivery times are displayed at checkout once your address has been entered. Outside the European Union, import duties and taxes remain the responsibility of the recipient. Delivery times run from the date of dispatch, excluding bank holidays.

Frequently asked questions

10 questions

6 key questions, 10 in the detailed view

What exactly is this module for?

How many pots can be connected to the reservoir?

The practical limit is autonomy, not the mechanics of the valve: four pots empty the 45 L reserve four times faster than a single one, and beyond four or five well-developed plants in summer, the reserve lasts only a few days. Count how many pots you are willing to refill each week, and size the network accordingly. Send us your setup through the contact page if you are unsure, and we will go over it with you.

What is the difference from the four-pot kit, which already has its own reservoir?

The four-pot kit is a complete set: the pots, the reservoir and the control system are already brought together and sized for one another. This module is the reservoir part, sold on its own: it contains the reservoir, the control pot, the valve, the pump and the fittings, and no growing pot.

You choose it in two cases: when you already own pots bought individually and want to stop filling them one by one, and when your setup does not have exactly four pots. The pots that carry the plants are then bought separately, or in the four-pot system that combines the two.

Is a power supply required?

What happens if the valve jams?

A valve stuck open empties the reservoir into the pots and overflows. A valve stuck closed lets the level in the pots drop without topping it up.

It is a simple part, but one that lives in a salt-rich solution: rinse the float and its seat each time you renew the solution, and check with a finger that it slides freely. Provide a drip tray or a floor that can withstand water beneath the installation.

Do all plants receive the same thing?

Where do you measure the pH?

It is measured in the control pot, which is the low point of the network and reflects what all the plants receive. There is no need to sample pot by pot: they are connected, and the sample would be the same.

The working range remains 5.8 to 6.2. Beware of one trap in the network: after a correction, let the pump circulate for a good hour before measuring again, otherwise you are reading the product you have just poured in rather than the system's solution. Our article on pH regulation explains the method in detail.

How do you install it, and can it be added to pots that are already growing?

Place the reservoir higher than the controller pot: gravity does the feeding.
Fit the float valve in the controller pot, on its half-inch outlet.
Connect the grow pots to the controller using the distribution tees and the tubing supplied.
Fill with clean water and watch for an hour to check that the valve shuts off properly before adding the fertiliser.

On pots that are already growing, the connection is made from underneath, without disturbing the grow medium or the roots. First bring their level down to the one set by the valve, otherwise their solution will flow into the controller pot and make it overflow at the first connection.

The job is done pot by pot, and takes about half an hour for a small network. The only tricky part is the setting up: the reservoir fits on top of the controller pot, and the whole assembly sits on a stable support, preferably in the shade.

Can the system be left outdoors?

Can it be used with pots from another brand?

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Constant-level water reservoir for growing pots, 45 L

The summary