OK Folks, class is in session.

And no, I am NOT the instructor.

I know enough about my tanks chemistry to keep me in business. But that's it. And I should probably know more. So... I have started this thread so I can ask multiple rudimentary questions about water chemistry and related issues, in the hopes that through a better understanding of the whole process, I can create a healthier tank for my animals!

So, here's Question #1

How often should I test my water parameters? Currently, I test weekly (or close to it).

Question #2

When I first purchased my tank, it was recommended that I buy a pH test kit. However, as time went by, I also ended up buying a KH/dKH kit. It seems that from a lot of the discussions I hear and read, there is some confusion between these tests and what they actually measure, as they are fairly similar in nature. So, please explain the difference between pH and KH/dKH test kits to me.

Question #3

As a follow up to question 2, let's say my pH AND my KH are both low. So, I do the calculations, reach for my SeaChem additives and prepare to dose my tank. First, between the buffer (pH), Alkalinity and Calcium, in what order should I drip/dose? I know to leave at least 30 minutes between treatments. But does it matter what order I dose??

I ask question #2 because as I understand it... KH/dKH is a measure of ALKALINITY.

But that's what I thought pH has been about.

Obviously they aren't the same. So what is different about them and why should we test for both.

OK now... no hoarding knowledge on TR, Rob will tell you that's against the rules... :)

:bump:

Jeff, I'm with you on the confusing nature of the terms vs. the test kit vs. reality in reef chemistry. Here's my take:

Testing intervals for me are more like every 2 or so weeks on pH and Alk. This is only because over time I was getting consistent enough readings that it didn't seem necessary to waste the money. I'll test extra times if I see a problem or suspect a problem.

Calcium testing I do weekly because I have calcium hungry clams and sps.

The difference between pH and Alkalinity is that pH is a measurement of current acidity/base of your water whereas Alkalinity is a measurement of the water's ability to neutralize acids that might be introduced. The KH (abbreviation of Karbonat Haerte, German for Carbonate Hardness) is measured in degrees of KH, thus dKH. If I recall, it tests the total amount of carbonate and bicarbonate ions in the water because they are the primary contributors to Alkalinity of water. Thus, there can be a difference between what the Carbonate Alkalinity test shows and your actual total Alkalinity.

The Seachem answer is begin with buffer. The buffer will not only adjust your pH, but raise your Alk as well. Always test more when you are dosing to correct an aberration (as opposed to routine maintenance). If when your pH gets back to 8.2-8.3 you are still low on Alk, you should use some alkalinity dosing. Seachem Calcium supplements don't affect pH or Alk, so those should be dosed normally. Bear in mind, however, that a lowered pH and Alk can cause precipitated calcium which is not good. I recommend stopping your regular calcium dose or curtailing it by at least 1/2 if you are fighting a pH/Alk problem. A chronic pH/Alk problem is usually indicative of a greater issue, however, and should be treated at the source, not the symptom.

There are people here with a much better grasp on chemistry than I have, so please add/correct if I got some part of it wrong.

I should also add that many times people refer to basic solutions as "Alkaline" because the salts that create them are referred to as "Alkali". Combine that with the basic pH of our seawater and people refer to the pH of seawater as "Alkaline".

The confusion is caused by the common reference to measuring something's "Alkalinity" (often heard in reference to soil) when what is actually being measured is pH, not Alkalinity.

I test when I do my weekly water change.