Drip Chlorination & Unclog the Emitters

Drip emitters have tiny outlets that clog easily. The biological culprits are algae growing in sunlit lines, bacterial slime, and iron or sulphur bacteria that build up inside the tubing. Physical sediment and chemical scale also clog drippers, but chlorination specifically targets the biological clogging — the algae, slime and iron bacteria.

Injecting chlorine (usually sodium or calcium hypochlorite) to a target concentration oxidises and kills the algae, bacterial slime and iron bacteria inside the system. The aim is to hold an effective chlorine level all the way to the far end of the lines for a contact period, then flush the dead matter out through the line ends.

The chlorine needed is the system flow times the run time times the target concentration. Flow times run time gives the volume of water treated, and multiplying by the target ppm gives the mass of chlorine to deliver. The product needed then depends on how much available chlorine your product actually contains.

A continuous low dose of about 1–2 ppm of free chlorine at the far end controls slime, while a periodic shock of 10–30 ppm clears established clogging. Use the higher shock dose for a heavy buildup and hold it long enough to reach and disinfect the ends of the lines.

Chlorine products are not pure chlorine. Liquid sodium hypochlorite is typically 5–15% available chlorine, and calcium hypochlorite (bleaching powder) is around 30–70%. The product needed depends directly on this strength — a weaker product means you must add more of it to deliver the same chlorine dose.

Dry products like calcium hypochlorite are dosed by weight, so the kilograms matter, while liquid hypochlorite is added by volume, so litres are easier to measure into an injector tank. Giving both lets you use whichever product you have without converting by hand.

Chlorine kills the biological growth but leaves dead algae, slime and oxidised iron in the lines. If you do not flush, that debris settles and can re-clog the emitters. Open the line ends and run the system until the water comes out clear; the tool estimates the water needed to flush.

At normal shock doses chlorine is broken down quickly and is safe for the crop, but inject when not watering sensitive seedlings, follow the product label, and avoid mixing chlorine with acids or fertilisers in the same injection. Wear gloves and eye protection when handling concentrated hypochlorite.

It depends on water quality. Systems on surface or pond water with algae and bacteria may need a light continuous dose or a monthly shock, while clean groundwater may need it only occasionally. Watch for falling emitter output and slime at the ends — those are the signs it is time to chlorinate.

No. Chlorination clears biological clogging; mineral scale and chemical precipitates (lime, iron oxide) need an acid treatment instead. Many growers alternate the two. Use this tool for the chlorine side and pair it with the Drip Irrigation and SAR tools to manage water quality overall.