HI775 Fresh Water Alkalinity Checker- How to Use for Hydroponics

This is a cool meter for a very important and often overlooked water quality parameter. Check your freshwater alkalinity using calorimetry in minutes. Find out if your RO filters need servicing or just know what your alkalinity is if using one or more water sources for your garden.

NOTE* chlorine in samples will affect the measurement, so a carbon pre-filter will need to be used for certain municipal water sources.

HI775 is sold in the aquarium industry but has a lot of value for hydroponics. If using RO(Reverse Osmosis) water, your alkalinity is zero and pH will be easily adjusted, even unstable to a degree.
For no-till or hydroponics, base water alkalinity can cause pH to drift up over time. Conversely, low alkalinity can cause soil or media to become acidic over time affecting nutrient availability and reducing yields.

Alkalinity also tells you how much acid you will need to add to adjust pH and if you use dosers to take care of this task, you'll need to monitor and adjust frequently. Also, if using RO, this water will have an affinity for ions until it reaches equilibrium.

And here's an in-depth explanation of Alkalinity from Greenhouse Grower

Certain municipalities, Boulder County Colorado for example, use different reservoirs and the water quality can vary greatly in a day having really hard water one day and soft the next.