Solar-powered air pump for pond, 120 L/h, 5 W panel

A panel's output depends on the angle at which it receives sunlight. In France, you face it due south, tilted at around 30 to 45° from horizontal, which the stake's ball joint allows. Avoid shade from a tree, hedge, or wall during the middle of the day, as even partial shading on the cells causes output to drop sharply. In spring, as foliage develops, check that a spot chosen in winter remains clear, and move the stake if necessary. You can also tilt the panel more upright in winter, when the sun stays low on the horizon, and lay it flatter in summer, when it passes near its zenith at midday: adjusting twice a year is enough to recover a good portion of the output you would otherwise lose.

Warm water contains less dissolved oxygen than cool water, while fish, being more active, consume more of it. Sunny summer afternoons combine both effects, and that is precisely when the panel produces the most. The solar pump therefore delivers its best flow rate exactly when your pond needs it most during the day. It also reduces water stagnation, which encourages mosquito larvae, and the formation of a surface film that slows gas exchange with the air. In a drinking trough or a rainwater harvesting tank, this gentle circulation is often enough to keep the water clear and odour-free throughout summer. The drop in oxygen in the early morning, however, after a night without aeration, is not covered.

An aquaponic system installed in the garden is often a long way from the house. The kit aerates a floating raft grow bed, where the roots are permanently submerged, or a lightly stocked small pond. For a more heavily stocked fish pond, use it alongside a mains aeration unit, never as the sole source of oxygen, a warm night without aeration is enough to put fish in distress.

Wipe the panel with a damp cloth whenever dust, pollen or droppings build up on it, as a dirty panel produces less output. Every 2 to 3 months, remove the diffuser and brush it: limescale and algae block its pores and reduce airflow. Before frost sets in, bring the pump and diffuser indoors; the panel can stay outside, but store it along with the rest of the kit if the pond no longer needs aeration over winter. The kit is covered by a 2-year guarantee.