DKH and pH are much related to each other. There are many life forms in the salty tank that absorb carbonates. Calcareous algae are one of them. By a constant consumption, these carbonates that are responsible for our Alkalinity buffering system get depleted which leads immediately to higher acidity causing pH to decline. This critical relationship between pH and DKH must be detected on a regular basis.
By adding Royal Sodium Bicarbonate we make sure to keep our carbonates in the range of 8-10 DKH and in this way keep our pH in the desired level of 8.2-8.4
pH in a saltwater aquarium should be increased very slowly, preferably not more than a 0.1 increase over a 24 hour period.
For that reason, we have developed this powerful tool of Royal pH and DKH professional test kit, giving you the ability to measure DKH and pH in one step. If DKH is measured by you constantly day after day as it should be, then in the same time and no more steps you get also the pH readings with just an extra look into another chart. This test will give you the confidence that the close relationship in your tank between DKH and pH is kept and coral skeletal growth is not interrupted.
pH and KH - 1 Step only Test Instruction
Each kit will give you 150 tests.
1. Using the 5 ml syringe, add 5ml of aquarium water to the test vial.
Attention: before any use of the vial test, make sure it is washed with RO water only and dry it up with a soft paper.
2. Using the 1ml syringe, place the metal needle firmly.
Draw up the dKH/pH solution until the black part of the syringe is at the 1.00 ml mark.
• Before this step, ensure that the metal needle is empty of liquids and that it's submersed in water the entire time to avoid air entering to the syringe.
• The presence of small air bubble between the liquid and the black part of the syringe is normal and will not influence the result.
3. Start adding dKH/pH solution to the test vial.
• Pay attention that during the titration you will observe two color changes: from pink to green and from green to yellow (see the picture below).
• After first drop you will get solution with a pink color that will get darker.
4. Continue adding dKH/pH solution drop by drop into the test vial until the color will change from pink to gray (first point VpH):
• Swirl a little after each drop.
• The right point is gray color with no pink or green tone (addition of one more drop into the solution should add green tone to gray).
5. Read the position of the black part of syringe for VpH value (each division corresponds to 0.01 ml).
6. Continue adding dKH/pH solution 5-8 drops at the time until the green color of the solution will become brighter, then add drop by drop until you will get the olive color (second point VdKH):
• Pay attention that the right color is olive and not completely yellow.
7. Read the position of the black part of syringe for VdKH (each division corresponds to 0.01 ml).
(use the two upper lines of the table for alkalinity determination)For alkalinity determination, compare the obtained value of VdKH using the table
• Typical values of alkalinity in the aquarium are in the range of 7-11dKH
For pH determination you will need both VpH and VdKH values.
1. Find the measured VpH value in the left column of the table and the VdKH in the upper line.
2. Find the intersection of a line with the right VpH and the column below the measured VdKH and read the pH value.
• Typical values of pH in the aquarium are in the range of 7.6 and 8.4
According to the titration the VpH was found to be 0.72ml and VdKH equal to 0.05ml.
In this case the alkalinity in your aquarium is 11.4 and pH equal to 8.43 (see the picture below).
AquaHomeTest NO2+NO3 | Combi-Test for seawater-aquarium
AquaHomeTest Ca+Mg: Calcium+Magnesium | Combi-Test for seawater-aquarium
The Fauna Marin Phosphate Test is very high-resolution and can determine the phosphate concentration with a particularly high accuracy in the low concentration range between 0.01 and 1 mg/l with clear color recognition.
The carbonate hardness (KH) or alkalinity* of a water sample characterises the buffering capacity, i.e. the ability to maintain the pH value of the water. It is primarily defined by the proportion of hydrogen carbonate ions in the water. As the pH value increases, other basic ions such as the hydroxide ions also contribute to the alkalinity. The alkalinity should be tested in all aquariums regularly. If the alkalinity in the aquarium is too low, the pH value can sink (sudden drop in acidity) to a level which is life-threatening for many fish and invertebrates. In reef aquariums, an adequate alkalinity is essential for strong coral growth. On the other hand, an overly high alkalinity in saltwater tanks can lead to lime precipitates and also have a negative impact on coral growth.
*There are many terms in water chemistry to describe the buffering capacity with varying definitions. The term “carbonate hardness” is customary in reef- and fishkeeping; however, it is the alkalinity which is measured. In this test, both terms are used synonymously. The reading for alkalinity is usually given in degrees of German hardness (°dKH). You can find a table for converting this unit into other common units (such as the equivalence unit millival per litre (mval/l) or the volume of substance in mmol/l) on the second cover page.
Natural seawater has an alkalinity of 6.5 °dKH. The alkalinity in saltwater aquariums should range from 6 to 9 °dKH.
Ask your specialist retailer for the correct alkalinity for your tank.
How to correct unfavourable values:
To increase the alkalinity when levels are too low, we recommend using Fauna Marin Carbonate MIX or Fauna Marin Easy dKH.
Contents of package: