how to make 4dkh solution


New Member
21 Dec 2008
hi i am trying to make 4dkh solution..... iv tried once but i think its not right,iv gone out and brought all the stuff to make it , 1 liter deionised water&bicarbonate soda but my electric scales that are not really precise to measure 1 gram ,i only have measureing spoons 1/4 1/8.1/2tsp 1tsp .the stuff iv made up when you put 5m in the drop checker and add 2 drops of the blue ph solution it turns green straight away.the way i made it was to make a solution with deionised Wat and the bake soda and then keep adding little bit to the plan deionised water till i got 4dkh,iv tested it with my test kit which is a hagen and it was changing at 60 to 70 ppm but i no the test kits are not very precise.... :?

could i use ro water instead of deionised water

Ed Seeley

3 Jul 2007
You can make your KH test kits more accurate by altering the way you do the test.

Most are designed so that 1 drop of reagent = 1dKH when using 5ml of water. If you double the volume of tank water then 1 drop = 0.5dKH. Double it again (20ml) the 1 drop = 0.25dKH. Use 50ml and 1 drop would equal 0.1dKH.

However the problem is that it can be very hard to spot the colour change in the diluted water when at larger volumes and you will use half of your reagent bottle performing the test!!!

Also make sure that you use the bottle completely upright so the drop is a properly calibrated drop and make sure you are very accurate with every stage of the measuring process and the accuracy of most test kits are much improved.

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