The two most important factors in water and nutrient management are pH and conductivity, and a good understanding and command of these variables is essential for successful hydroponic gardening. pH is the measure of acidity or alkalinity of an aqueous solution.  If a solution is acidic then it has a pH in the range of 0 to 6.9.  If a solution is alkaline then it has a pH in the range of 7.1 to 14.  Pure water or deionised water is neutral at pH 7.0.  The ideal pH for most hydroponic gardening applications is between 5.8 and 6.2, except for Rockwool cultivation, which likes a slightly lower pH of about 5.5. If the pH of a solution is not within the correct range the plant will not have the ability to absorb some of the essential elements required for proper plant growth.  All plants have a particular pH range, which will produce healthy growth, and this level will vary from plant to plant, but most plants prefer a slightly acidic growing environment (5.8 to 6.2), although most plants can survive in an environment with pH values between 5.0 and 7.0.

Plants grown in acidic environments can experience a variety of symptoms, including aluminium (Al), hydrogen (H), and/or manganese (Mn) toxicity, as well as nutrient deficiencies of calcium (Ca) and magnesium (Mg). Conversely, in alkaline environments molybdenum (Mo) and macronutrients (except for phosphorus) availability increases, but phosphorus (P), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu) and cobalt (Co) levels are reduced, and may adversely affect plant growth. From the chart you can see that each element can become more and less available to the plants as pH changes.  If the pH of your solution is out of the desired range, one or more of the essential elements will become unavailable to the plant, causing nutrient deficiencies, which will result in slow growth rates, and poor yields. There are a few ways to check the pH of your nutrient solution, such as paper test strips, liquid pH test kits, and digital pH meters.  The paper test strips are impregnated with pH sensitive dyes, which change colour when dipped into the nutrient solution. 

The paper strip is then compared against a colour chart to determine the pH of the solution being checked.  The liquid pH kits work by adding a few drops of pH sensitive dye into a small amount of the nutrient solution and then the colour of the resulting liquid is compared against a colour chart. The most high-tech method of checking the pH is with a digital meter.  All you have to do is dip the meter/electrode into the nutrient solution for a few moments and the pH value is shown on an LCD display.  The pH meters are fast and very accurate when properly calibrated.  These meters need to be cared for properly or they will no longer function.  The glass bulb electrode needs to be kept clean, and some are required to be kept wet at all times.  pH meters also need to be checked and calibrated frequently to insure accuracy. Usually for this type of cultivation we would recommend that the grower makes up one large container of nutrient at a time. A 200 litre plastic drum is an ideal container.

Once this is made up to the correct ‘strength’ (conductivity), the pH can be checked and adjusted to the ideal level of 5.8-6.2. fish tank water hardnessA careful note should be made of the exact amount of pH UP or pH DOWN that is added at this time. fish tank perth gumtreeIn future, this amount can be added as a routine when making up solutions, and pH should remain pretty constant from batch to batch, although spot checks are recommended from time to time. fish tank lights 3ftIdeally you should use a meter, for example, BlueLab pH pen. giant fish tank berlinThe nutrient solution in the tank should remain stable and can be applied to plants as needed.round fish tank brisbane

Active hydroponic systems are ones in which the nutrient solution is supplied to the plants by a pump system. small fish tank temperatureThese systems include NFT, Flood & Drain, Aeroponics, and DWC Systems. In most systems the nutrient solution is re-circulated to the roots continually over a period of time. In an active system the pH will need checking and adjusting in the main tank on a regular basis. In most systems fresh water is added to the tank to replace that used by the plants. The incoming water is usually of a higher pH than the nutrient solution, so there tends to be an upward drift in pH. This can be corrected by the regular addition of small amounts of pH DOWN. This process of pH control can be carried out with pH kit but as it needs doing often in this system, the busy grower would be better off using a meter. Hard water is characterized by high levels of bicarbonates and it makes itself known by depositing lime scale in kettles and by reducing the lathering ability 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 neutralized and this uses up quite a lot of acid.  The obvious problem for the grower is that he will be adding quite large amounts of acid on a regular basis.  If he is using phosphoric acid this may lead to a build up of phosphate in the nutrient tank over time.  High levels of phosphate in the solution can inhibit the uptake of other elements, zinc for instance, and cause general nutrient imbalance. Fortunately, properly formulated ‘Hard Water’ nutrient solutions, such as Ionic HW are designed to address this problem.  Conversely you could use a reverse osmosis system to filter your water, and then use the ‘regular’ soft water nutrients. ALWAYSAlways keep them out of reach of children.DOG CAT Correct pH For African CichlidsTanganyikan and Malawian cichlids will prosper and breed at pH values as low as 7.2 and hardness values to 3 DH.

Q.From books, fish magazines articles and word of mouth, I’ve learned that it is best to keep the pH of the water in an African cichlid fish aquarium between 8.0 and 8.2. Possibly because of my routine of frequent water changes, I’ve never been able to get a reading higher than 7.4 from my aquarium water despite the use of coral gravel for the substrate. Does this lower pH value pose any problem to my fish? If so, is there any other way of raising it other than through the use of a commercial buffer solution? A.Your question would be easier to answer if you had specified exactly which African cichlid fish you are keeping. Because you have expressed concern over whether your pH is sufficiently high to keep your fish healthy, I assume you are keeping either Lake Malawi or Lake Tanganyika cichlid fish. Published pH values for Lake Malawi range from 7.7 to 8.6, and for Lake Tanganyika from 7.3 to 8.0. Reported hardness values for Malawi range from 6 to 10 degrees of hardness (DH) (125.0 to 170.5 parts per million total dissolved solids — ppm TDS), and for Lake Tanganyika from 10 to 12 DH (170.5 to 205.0 ppm TDS).

Experience has shown that both Tanganyikan and Malawian cichlid fish will prosper and breed at pH values as low as 7.2 and hardness values to 3 DH. What seems critical is the stability of these values rather than their absolute magnitude. Your use of coral gravel as a filter bed provides all the stability your fish require given the relatively hard, alkaline character of the tap water where you live (Southern California).What is far more critical to successful husbandry of rift lake cichlid fish is proper nitrogen cycle management. These cichlid fish are extremely intolerant of ammonia and nitrite. The program of regular partial water changes you presently practice may depress the pH in your aquarium somewhat, but its contribution to the well being of your fish far exceeds any imaginable benefits from a higher pH. Your management practices are exactly those I would recommend to a prospective rift lake cichlid fish aquarist. Just keep up the good work and don’t lose any sleep over those pH values.african cichlids ·