fishguy449
New member
I have a Aquarium Pharmaceuticals GH/KH test kit for freshwater. Is there a conversion for the readings so that I can use it on a sw setup?
Freshwater KH Kit
- Thread starter fishguy449
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The GH part is not very useful, as it is a combination of calcium and magnesium. I presume the KH part is OK, but it may not go high enough. Does it give a range? It might allow higher levels by adding more titrant. What units does it use?
fishguy449
New member
You start with 5ml of test water. First drop of test solution turns the water blue (at least it did for my fw tank - have not tried it on sw yet). You continue to add drops of test solution, mixing by inverting the tube after each drop is added. The test is done when the final drop turns the water from blue to yellow. The reading is # of drops read as degrees dKH, or you can multiply # of drops times 17.9 to get ppm. The table that came with instructions lists up to 16 or 286 ppm KH. Thx for the help.
OK, so that is giving results in dKH and ppm CaCO3 equivalents, which are just different units of alkalinity
1 meq/L = 2.8 dKH = 50 ppm CaCO3 equivalents for alkalinity
I recommend 2.5-4 meq/L; 7-11 dKH, or 125-200 ppm CaCO3 equivalents
1 meq/L = 2.8 dKH = 50 ppm CaCO3 equivalents for alkalinity
I recommend 2.5-4 meq/L; 7-11 dKH, or 125-200 ppm CaCO3 equivalents
fishguy449
New member
i will check for 7-11. I'm assuming that you are saying go ahead and try the fw kit and see what it reads. I'll let you know what I measure. Thx again.
Yes, it sounds like it should be fine. The true differences between alkalinity in freshwater and seawater probably eludes most manufacturers anyway, and I expect the kit titrations are all the same.
fishguy449
New member
The tank tested at 5 dKH, Ca = 450 and ph 0f 8.2. Just to try and verify the test I checked some fresh mixed IO in RO/DI water. It tested at 10 dKH. While reading your article on chemistry and corrections, I figure that I'm low and to the right in your graph or slightly into zone 4. The recommendation in the article is with my ph to use baking soda to raise the alk. This is my plan. I am planning on doing a 10-15% water change this weekend which I have been doing about every 10 days. I'm wondering if I should go for all of the correction at one time or slowly bring it up over the next few weeks?
fishguy449
New member
Never mind Randy. When I used the calculator it suggested slow dosing while monitoring pH, which I will follow.
thx rayjay, it's good to hear someone else has already tread the path I'm on.
thx rayjay, it's good to hear someone else has already tread the path I'm on.
I'd bring the alkalinity up all at once. 
fishguy449
New member
a friend of mine bagged up some seachem buffer yesterday. i saw the bottle said it was to raise and maintain pH to 8.3 Can I use this in lieu of the baking soda? Will it bring up my alk?
Yes, that will work fine to boost alkalinity. Don't count on the pH 8.3 line, however. 
fishguy449
New member
thx. pH is already 8.2 an Ca 450 as stated above, so was just trying to boost alk at this time. thx again.
:thumbsup:
good luck.
good luck.
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