6 Hard Water

Hard water is characterised by high levels of Bicarbonates and it makes itself known by depositing lime scale in kettles and by reducing the lathering capacity of soap. Hard water will usually have a high pH but not necessarily. What will distinguish hard water is that it will take much more acid to reduce the pH than with an equivalent sample of softer water. This is because the Bicarbonates have to be neutralised and this used up quite a lot of acid.

The obvious problem for the grower is that he will be adding quite large amounts of acid on aa regular basis. If using Phosphoric acid this may lead to a build up of Phosphate in the nutrient tank over time. High levels of P in the solution can inhibit the uptake of other salts, Zinc for instance, and cause general nutrient imbalance.

Solutions to hard water problems

1. The first and most obvious solution is to change the nutrient tank regularly. This will reduce the chances of Phosphate accumulation and ensure maintenance of a good nutrient profile. Frequency of changes will depend on tank size and number of plants. In very Hard water arias however a large amount of Phosphoric acid will be needed to correct pH when nutrient is first made up.


2. It is possible to use Nitric Acid to control pH. This will overcome the problem of phosphate accumulation but Nitric Acid is a very unpleasant and dangerous liquid. It should never be handled by anyone who is mot experienced with aggressive liquids and all good laboratory procedures should be observed. NItric Acid will only solve the Phosphate problem, it will not make any difference to the high levels of Calcium and other minerals which will eventually accumulate in the tank.


3. Best Solution by far is to use a specific formulation which is usually based on more acidic components. Hard water General Hydroponics Flora Range was formulated in response to demand from growers in various areas of t he United Kingdom such as London, Thames Valley and other arias with very hard water. It was formulated to correct the pH of alkaline water and minimise the amounts of Phosphoric Acid that are required to maintain it at correct levels. It also takes account of the other minerals to be found in Hard water use of this product will ensure the best possible results in Hard water areas.


4. A reverse Osmosis Filter (R. O unit) will remove the mineral ions by passing water through a very fine membrane. The water produced can be very pure and will allow normal nutrients to be used with complete confidence.