NFT hydroponic kit : 36 plant sites & pump included

Water from a fish tank carries suspended solids that the nutrient film does not tolerate well. Particles settle on the bottom of the channel, thicken the film, and eventually block the joints between levels. If you feed this tower from a pond, upstream mechanical filtration is a prerequisite for reliable operation. The rest of the installation remains unchanged: same pump, same gradient, same baskets. What you gain in return is water that already carries its nitrates, derived from the nitrogen cycle, meaning nutrition to be topped up rather than built from scratch, with particular attention to iron and potassium, which pond water tends to supply poorly. The pH range also shifts: a stocked pond typically sits around 6.8 to suit both fish and bacteria, at the cost of slightly reduced availability of certain elements for the plants.

Between cycles, the tubes come apart and are rinsed under clean water with the lids open. What you are looking for is the slippery biofilm that forms on the floor of the channel and traps particles during the next cycle. Spent germination sponges are discarded; the baskets are rinsed and reused. Allow a good hour for the 4 tubes, and take the opportunity to empty the tank and scrub its walls, since deposits start there. The pump strainer is rinsed at the same time, a partially blocked filter reduces flow well before the mesh looks visibly clogged.

Without a grow medium to buffer it, the solution changes quickly and should be corrected towards 5.8 to 6.2, the range in which nutrients remain available. Readings are taken once a week in an established crop, every 2 days in the early stages, and always in the tank rather than in a tube, the sample there being representative of the entire circuit. The solution is made up fresh every 2 to 3 weeks, with evaporation topped up in the meantime using plain water. A rising conductivity while the level drops indicates that the plants are taking up water faster than mineral salts, and a top-up of plain water corrects this more effectively than adding more fertiliser.

The tower takes up less than half a square metre of floor space and requires height above all, with the tank sliding beneath the structure. The slope of the tubes is set during assembly and should be gentle, around 1 cm per metre is enough to keep the film flowing without it pooling at the bottom of the channel. Pay equal attention to lateral levelling: a tube tilted to one side will leave the opposite edge dry, meaning some positions on each row receive no water. Allow access on one side to open the tank, take measurements and top up without moving the whole unit, and ensure a reliable power socket is nearby for the pump. Assembly itself is done dry, then a first fill with clean water, run the pump for one hour to check the seals at every joint and confirm an even film across all 4 levels before a single plant goes into a net pot.