I have been using Mardel test strips to test my kh and gh since that was the only thing they had at the lfs. I was ordering some other stuff the other day and saw the Aquarium Pharmaceuticals Kh & Gh test, so I bought it, since I use their other tests for everything else.

So, I tried the kh test out and can't quite figure out if I am getting the results correct. It says to keep adding a drop at a time, invert, wait a minute and if the water turns yellow then that is your kh level (at least that is how I interpreted the instructions). It also says that the drop should go in blue then turn to yellow after inverting the test tube, and when I add the drop(s) it does not turn blue at all. Well, after my first drop and inverting a few times the water turned a tiny bit yellow, but you could barely tell, only if you held the test tube up to a white background. So I added another but it basically stayed the same. The third drop made it more yellow, so I quit at that point, although not sure if I would call it "bright" yellow-it looks a bit like the API ammonia test if you have no ammonia, but maybe not quite as bright. The drops never looked blue to me at all, even as soon as they hit the water. When they hit the water they looked orangish-yellow.

So, I know that my kh is really low, practically non-existant in my tap water, which is why I have crushed coral in my filters and monitor it closely in the first place, otherwise my tank ph crashes. So does it sound like I am doing this test correctly?

And from what I understand, if it *was* considered yellow after the first drop that would mean my kh is 1 dkh OR 17.9 ppm, after 2 drops: 2 dkh or 35.8 ppm, after 3 drops: 3 dkh of 53.7 ppm-in either case way too low. I thought I had two test strips left so I could compare the results and make sure I was performing the test accurately. but I cannot find the strips. Plus I know that they are not all that accurate in some cases anyway, which is why I bought these drop kits in the first place! The last time I tested the kh with my strip it read at 80 ppm, and that was about 2 weeks ago, could it have dropped that much? Perhaps my coral is wearing out.

Thanks for any help with this, hope I didn't confuse you too much!

Here are the directions for the test, if it helps-I abbreviated the standard parts of the instructions like how much water to add, inverting, etc but left the important instructions verbatim:

First part is the usual 1. use clean test tube, 2. add 5 ml of water.

3. Add Carbonate Hardness test solution, one drop at a time, holding dropper bottle upside down in a completely vertical position to assure uniformity of drops. After first drop is added solution will turn blue. If the water sample contains only 1 dkh the solution will turn from clear to it's yellow endpoint after the first drop is added.

4. Cap test tube and invert several times after each drop. Keep count of the drops being added. Do not hold finger over end of test tube as it may affect the results.

5. The test is completed when the water in the test tube, after having been shaken, turns from blue to yellow. If you have difficulty discerning the color after the first drop of solution is added, remove the cap from the test tube and while holding it over the a white background look down through the tube.

6. The Carbonate Hardness value is determined by the number of drops of the reagent that must be added to turn the water in the test tube bright yellow. Each drop is equal to 1 dkh or 17.9 ppm KH.

You're doing the test correctly. The reason water in the test tube doesn't turn blue is because your water contains less than 1 dkh carbonate hardness. With water that has a kh that low, the PH of your water could easily crash. The crushed coral you're using doesn't seem to be helping much. You might want to consider adding baking soda to the water to get the kH level up to at least 4.5 dkH. Raise the kH slowly, you don't want the PH to raise more than .2 - .5 per day.

Here's a link to a baking soda calculator that will tell you how many TEAspoons of baking soda to add.

http://dataguru.org/misc/aquarium/calKH.asp

Thank you SO much! I hate my water. I did have the kh up to 80-100 ppm, which was holding the ph steady for the last 2 1/2 months, but the same thing happened 3 months ago, the coral seemed to have "worn out". So I *think* it works ok, I just need to change out the coral.

The reason I have been hesitant to use the baking soda is because I am in an overstocked tank (soon to remedied) and I change the water every third day, sometimes more often. So I try and keep my ph at 6.8 (same as my tap water) so the tap water matches exactly and I don't have to mess with anything for water changes. If I raise the kh and ph with baking soda then I have to mess around with the tap water every water change-not a huge big deal, but it certainly makes things easier. Also, when I used that calculator before, in order to make my kh high enough, I think it was going to raise my ph way too high for the fish anyway-above 9. Unless I am doing the calculations incorrectly that is!

But, what do you think about the kh being 80-100ppm with the coral? That was keeping the ph at a steady 6.8, but like I said, the coral seemsto stop helping about 10 weeks in, but then if I change it everything is ok. Do you think that is ok, or should I look into using baking soda or something else? I wish there was a product that would raise the kh withOUT making the ph rise as well.

Thanks again for answering my question and I would love to know what you think, you are the chemical expert of Koko's!

Isn't messing with water chemistry fun? If you're able to keep the PH stable at 6.8, and the kH stays in the 80-100ppm range using nothing but crushed coral... You're fine. Just keep an eye on the kH level and change or add more crushed coral as soon as you see the kH level start to drop.

If you want to raise the kH without raising the PH... You only have one choice... CO2 injection.

Thanks Bak...you are so good at this stuff! I think that is the first time i have received a straight answer on "Can you raise the kh without raising the ph?"

I am going to have to see how well the crushed coral will work in the 55 gallon though, I will probably have to use more and it will "wear out" faster...that is why I bought these better test kits in the first place because I knew I'd have to be monitoring a lot! I will probably put a nylon full of it in the back of both the Emperor filters and see how that goes. Stupid no-buffer water!

My fiance has issues with it too because he is in charge of taking care of the swimming pool here but of course the poolwater doesn't have to pass through anyone's gills so the chemicals are probably easier....

Thanks again!