Geraldine Aquaponics Kit

From one model to the next, the pond stays the same and only the growing area changes: it doubles, from 1 to 2 m², with a volume of clay pebbles rising from 210 to 420 litres. The footprint follows, from about 2.3 m² for the Géraldine 1 to 4.2 m² for the Géraldine 5, and it is most often what decides the choice. So measure the space you have available, allowing for a path to harvest and to reach the siphon. The Géraldine 1, long and narrow, fits nicely along a wall or a hedge, whereas the Géraldine 5 needs an almost square area.

A new system needs 4 to 6 weeks before it can handle the load of a stocked pond. The nitrifying bacteria supplied with the kit begin colonising the clay pebbles, then their population grows with what the pond provides them. During this period, the ammonia level rises first, then the nitrite level, before both fall: their return to 0 mg/L shows that the biological filter is established. You monitor the water with a test kit 2 to 3 times a week, you start with few fish and a light ration, and you then increase the stocking. The water conditioner supplied is for the first filling, to neutralise the chlorine in mains water that would destroy the bacteria you have just introduced. Filling the system in spring spares you from starting in cold water, where nitrification slows considerably.

The garden bed is a media bed of clay pebbles, regularly flooded and then drained by the siphon, and this grow medium supports both the roots and the bacteria. It suits crops that root in a well-drained medium: lettuces, herbs, chard, strawberries, and medium-sized fruiting plants, such as cherry tomatoes or peppers, if you stake them against the structure. The working height of 92 cm lets you sow, transplant and harvest standing up. The pH aimed for in aquaponics sits between 6.4 and 7.5, a range that suits the fish, the bacteria and most leafy vegetables alike. The plants suited to aquaponics are presented one by one in a dedicated article.

Once the system is up and running, upkeep comes down to a few regular tasks. Check every day that the pump is running, that the water stays clear, that the level is correct and that your fish are eating normally. Measure the pH and the nitrogen compounds every 2 to 3 days while the system is stabilising, then space out the checks. Make up for evaporation and plant transpiration as soon as the level has dropped by a few centimetres, using water that has been left to stand at a temperature close to that of the pond. Finally, remove dead leaves from the vegetable bed and deposits from the bottom of the pond rather than emptying the whole volume, since it is the vegetable bed that acts as the filter.

The frame is solid pine and carries two watertight tanks in polyester resin or HDPE, fitted inside: the wood never touches the system's water. The kit arrives part-assembled, so some of the assembly has already been done in the workshop and you still need to finish the frame, fit the pre-assembled pipework and the siphon, then fill with the clay balls. Allow for the empty weight, 109 kg for the Géraldine 1 and 189 kg for the Géraldine 5, to plan the handling: once filled with water and clay balls, the whole unit can no longer be moved.

The kit includes the solid pine frame, the two watertight tanks, the pump with its 10 m of cable, the pre-assembled pipework, the automatic siphon, the clay pebbles in the quantity suited to the model, and the starter products: water conditioner and nitrifying bacteria. You then set up the pond according to the season in which you fill it and what you want to harvest. If your project is more about ornament than cultivation, the small garden aquaponics kit with a 500-litre pond meets that need.

On delivery day, clear access to the final location and two people to handle the unit will save you time. Delivery with installation and commissioning can also be arranged in mainland France. Please tell us via the contact page before ordering, with details of site access and the nature of the ground, so that the date can be set accordingly.