as part of my arduino controlled irrigation, there is a flow meter sampled by arduino who sends me an email should the flow divert too much from the value attached to each valve. This summer i replaced the flow meter (1", 10 $ from ebay) because it was blocked, probably because it stayed idle during the winter. The new one (same type) is rather imprecise, almost useless below 50l/h. Can someone here recommend a (reasonable quality and cost) flow meter covering 10-2000 l/h.
Those are essentially 'toys', how about using a proper water meter (they come in a wide variety of ranges) and either have internal pulse sensors or external clip-on ones. They should be much more robust.
I've never had occasion to buy one, the water companies install them here for free (or included in your bill), but there are a huge variety of different types and sizes.
SINGLE-JET CLASS B COLD WATER METERS (50C) - Dry Dial, MID + WRAS Approved, Horizontal / Vertical Installation, NNK Pulse Transmitter can be ordered with or retrofitted
I would expect you should be able to find something similar locally, water companies worldwide tend to do very similar things - and monitoring water meters is a very common part of their work. Much of our business at work is involved in it, and our core business is probably manufacturing and supplying splitters to feed multiple devices from a single meter.