First Approach: Adjustable Drippers (0–40 l/h)
The initial drippers used were adjustable flow drippers rated 0–40 l/h. These are the most commonly available type for micro-irrigation and appeared to be the logical starting point. In practice however a persistent problem emerged: at any given time, one or more drippers would fail to deliver flow while others ran normally. The most likely cause is the pressure gradient along the distribution pipe — drippers closer to the pump receive higher pressure than those at the far end of the closed-end pipe, and with non-compensating drippers this differential is sufficient to cause the low-pressure units to remain closed or deliver inconsistent flow. Despite repeated adjustment, reliable uniform distribution across all drippers could not be achieved.
Current Solution: Claber Self-Regulating Pressure-Compensating Drippers
Switching to Claber pressure-compensating drippers solved the distribution problem entirely. These drippers maintain a constant output of 4 l/h across a wide range of inlet pressures, compensating internally for the pressure gradient along the pipe. All drippers now deliver consistent flow regardless of their position on the distribution pipe.
Dripper Specifications
| Parameter | Value |
|---|---|
| Type | Pressure-compensating, self-regulating |
| Flow rate | 4 l/h |
| Operating pressure | 1.5 bar |
| Manufacturer | Claber |
The Whistling Problem – and Its Resolution
The pressure-compensating drippers introduced a new issue: a faint but noticeable whistling sound after each pump cycle. With a non-return valve installed, residual pressure in the closed-end pipe had no path to dissipate when the pump switched off. The pressurised drippers released this residual pressure slowly over several minutes, producing a persistent whistling noise at each dripper outlet.
The solution was to remove the non-return valve entirely, allowing system pressure to equalise immediately when the pump stops. This eliminated the whistling almost completely.
In context, the remaining faint sound is acceptable: the pump runs only three times per day for approx. one minute each, exclusively during daytime hours. There is no overnight operation, so the noise is never present during sleeping hours. A brief whistle three times a day for a few seconds is a reasonable trade-off for the reliability that pressure-compensating drippers provide.
A Note on Dripper Choice
Various guides recommend adjustable drippers as a straightforward and cost-effective solution, and for many installations they work well. In retrospect, the flow inconsistency experienced here is likely related to the pump choice rather than the drippers themselves. The Reich camping pump operates at a relatively modest maximum pressure of 1.1 bar – at the end of a closed-end pipe this may simply not be sufficient to open all non-compensating drippers reliably against the combined resistance of the system. Installations using a stronger DC pump would likely not encounter this issue, and adjustable drippers would be a perfectly valid choice in that context. For this specific combination of pump and pipe layout however, pressure-compensating drippers proved to be the more reliable solution and are what the system currently runs on.
The Inline Filter — An Essential Component
When the system was first set up, no inline filter was installed. The consequences became apparent quickly: the drippers blocked, flow became uneven, and the yucca saponin experiment accelerated the problem considerably. Adding an inline filter was one of the most impactful single improvements made to the system.
The Filter
The filter used is a fine water filter with a 0.1 mm mesh, sourced from Amazon. Like the pump, it comes from the caravan and motorhome supply world — which is convenient, as it is dimensioned for the same hose diameters that the Reich pump supports. No adapters or reducers were needed; it integrates directly into the existing plumbing.
The filter is installed immediately after the pump, before the distribution pipe and drippers. This is the correct position: everything downstream of the pump — including the pressure-compensating drippers with their small internal passages — is protected from particulate matter.
Why It Is Essential
Pressure-compensating drippers have small internal membranes and orifices that are vulnerable to even fine particulate matter. A single piece of debris is sufficient to partially or fully block a dripper, and in a closed-end system where pressure distributes unevenly, a blocked dripper is not always immediately obvious. The filter prevents this reliably.
The pump’s own built-in pre-filter is not sufficient for this purpose. It catches coarse debris — fragments large enough to damage the pump impeller — but passes fine particles freely. The 0.1 mm inline filter handles what the pump’s pre-filter misses.
Cleaning
The filter is cleaned at every full tank refresh — every 4–6 weeks as part of the routine maintenance cycle. Unscrew, rinse under running water, reassemble. It takes about two minutes and fits naturally into the same session as draining and refilling the nutrient solution.
The Coarse Pre-Filter at the Gutter Return
A secondary filtration stage is installed at the tank bulkhead fitting that receives the return line from the rain gutter. A fine nylon mesh is fitted over this inlet to catch larger debris — small plant fragments, detached fleece fibres, and anything else that may wash down from the wall surface.
Recommendation
Do not omit the inline filter. It is inexpensive, takes minutes to install, and prevents a category of problems – blocked drippers, uneven flow – that are disproportionately difficult to diagnose and fix after the fact. Install it from the start.