Tropical aquarium fish need warm water. Tropical aquarium plants also need warm water, not only around their leaves, but also at their roots. In nature, apart from the naturally warm stream bottom the plants grow in, there are usually abundant 'nutrient springs' caused by ground water seeping up through the earth and into the stream water, bringing with it, fresh nutrient for the plants. However heating just the water in an aquarium does not replicate this natural condition. Warm water rises, and cold water sinks, leaving the plant roots in cold and often stagnant water.
The logical solution to this problem is bottom or substrate heating. With this method, the warm water from the bottom, rises up through the substrate and into the aquarium, while the cooling water sinks down, bringing fresh nutrient back into the substrate where it is made available for the plants to take up through their roots.; There is a wide range of Dupla substrate heating systems available to suit all size aquariums and budgets. All systems comprise a silicone heating cable which is laid on the bottom of the aquarium under the substrate. To provide a high level of safety and convenience, this cable runs on 24V.
For aquariums up to 360 litres, there are the Dupla Thermik Set 120, 240 & 360. These sets provide heating for the substrate only, and are therefore in most situations able to be used without a thermostat. Running continuously, a gentle bottom warmth and circulation is provided for the plants. A normal immersion heater with integral thermostat is used to provide the majority of heating for the aquarium water, and therefore temperature control for the fish.
The Dupla Heating System in Detail:
Thermik Sets
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These sets are primarily intended for providing continuous warmth in the substrate, while a conventional immersion heater manages the total aquarium temperature. This enables a very economical means of providing correct substrate conditions for aquarium plants. Dupla Thermik Sets are available as Thermik Sets 120, 240 360, comprising a 20W/3 metre, 40W/5 metre or 60W/7 metre silicone heating cable with matching 24V safety heating transformer, and are suitable for up to 360 litre aquariums.
Therm Sets
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The Dupla Therm Sets comprise a range of two larger and more powerful heating systems (Therm Sets 750, 1000) for providing not only bottom warmth, but entire aquarium heating.For the recommended aquarium sizes, a temperature controller must be used to regulate the heat. The sets consist of a Duplaflex 24V heating cable, cable anchors to fix the cable to the aquarium bottom, and a matched safety heating transformer.
Dupla Cable Anchor
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The Cable Anchor provides a convenient means of anchoring the cable to the aquarium bottom prior to covering with gravelDupla 24V Heating System Selection Guide
Aquarium Size in Litres |
Closed Aquarium in Room at 20-22°C |
1. Open Aquarium in Room at 20-22°C |
Open Aquarium in Unheated Room |
| up to 50 litre | Dupla Thermik Set 120 (20W / 3M cable) |
Dupla Thermik Set 240 (40W / 5M cable) |
Dupla Thermik Set 360 (60W / 7M cable) |
| 50 to 75 litre | Dupla Thermik Set 240 (40W / 5M cable) |
Dupla Thermik Set 360 (60W / 7M cable) |
Dupla Therm Set 250 (100W / 7M cable) |
| 75 to 200 litre | Dupla Thermik Set 360 (60W / 7M cable) |
Dupla Therm Set 250 (100W / 7M cable) |
Dupla Therm Set 500 (150W / 10M cable) |
| 200 - 300 litre | Dupla Therm Set 250 (100W / 7M cable) |
Dupla Therm Set 500 (150W / 10M cable) |
Duplaflex 750 (200W / 13M cable) |
| 300 - 500 litre | Duplaflex 500 (150W / 10M cable) |
Duplaflex 750 (200W / 13M cable) |
Duplaflex 1000 (250W / 17M cable) |
| 500 - 750 litre | Duplaflex 750 (200W / 13M cable) |
Duplaflex 1000 (250W / 17M cable) |
2 x Duplaflex 500 (2 x 150W / 2 x 10M cable) |
| 750 - 1000 litre | Duplaflex 1000 (250W / 17M cable) |
2 x Duplaflex 500 (2 x 150W / 2 x 10M cable) |
2 x Duplaflex 750 (2 x 200W / 2 x 13M cable) |
Notes:
The above table is intended as a guide - individual conditions for each aquarium installation can vary significantly. All specifications assume an aquarium temperature of 25°C. For higher water temperatures, the next largest heating cable or combination of cables should be used.
2) Dupla Thermik Sets (120, 240, 360) are designed to run continuously for substrate warmth in aquariums up to 360 litres.They may also be used with a Dupla T-Control for full temperature control of smaller aquariums as per table.
3) The maximum rated capacity of the Duplamat heating transformer must not be exceeded eg Duplamat 300 - 300 Watts max. If greater heating capacity is required, an additional Duplamat must be used.
Dupla T-Control Delta Alpha
For automatic control of temperature in the Aquarium, two controllers are offered:
Dupla T-Control Delta
Again for reasons of convenience and safety, the controller operates on low voltage. The mains voltage to the heating transformer is controlled by a remote power supply and switching unit which can switch up to 1000W (inductive) or 1500W (non-inductive). |
Dupla T-Control Alpha
The T-control Alpha also features programmable upper and lower visual and audible alarms to signal should a problem occur. |
Dupla Multi Control
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The T-Control Delta is an electronic Temperature controller using analogue technology. It features a green LED digital display for indicating set temperature and actual water temperature. The 'Set' button is pressed to change the display from actual to 'set' temperature. While pressed, the desired temperature is adjusted using the small pre-set potentiometer on the front panel.
The T-Control Alpha is a more sophisticated controller based on a RISC microprocessor. It uses a dual channel switching unit enabling new possibilities for temperature control in the aquarium. The main switching channel can control the substrate heating which may now be sized with only the substrate in mind, as the second channel can be used to control a supplementary heater to maintain temperature in the aquarium water.
The Dupla Multi Control Aquarium computer with six-way socket for control of all key parameters in freshwater and seawater aquariums using a single device. Enables pH-controlled CO2 fertilisation, while the the water temperature is regulated by a fitted temperature sensor. The socket for ground temperature management is controlled by way of the variable hysteresis to the water temperature and, due to an inverting function, allows a cooling device to be connected instead of the ground heating. Fitted with three time-controlled sockets for devices such as day/night lights, air and hydraulic pumps, or filters, which can be switched on and off up to 8 times per day.