water tests

Is it any surprise to have such huge differences in testing of parameters between the different brands of test kits?  I have asked a similar question before, but need further understanding.  I had my water tested at a LFS that uses the Hagen Kit.  Results for the CAL was 460, and ALK 14.  I recently purchased the API test kit knowing that once I start putting more livestock in the tank that I will want to be using the Salifert brand.  I purchased this kit due to price, knowing that I may be testing frequently while I get used to making adjustments to my parameters.  My results were quite different.  CAL 320-340, and ALK 9.  Another LFS has had results that deviate  from both the above mentioned also, and they use the Hagen as well.

I have used Salifert for a long time. I saw different readings between Salifert Alkalinity kits when I was the one doing the testing. I discovered it was a different manufacturing batch.

Of course it's not just the kit, but any person using it. Knowing when to read the color change is part of it. The question must be asked, "Do I stop adding drops when the color just begins to change or when it stops changing?" (You might be surprised at how many LFS employees don't know a thing about this, as well as a great many technical aspects of the hobby.) Here is a little "experiment" for you. The next time you test for Alk, note the point at which the color begins to change and then again when it stops changing. What are the Alk readings at those two points and how much difference is there?

Here is something that will also help. Knowing the approximate Alk and Ca of the salt mix and then averaging the results of the various tests by you and the LFS is the way to calibrate your own testing results. It's common in statistical analysis to throw out the highest reading and the lowest reading and take the average of what's left.

I think i would trust the api and sailfert tests. I agree with mark about looking at what salt mix you are using. Think if it this way your tank was just set up and if your not dosing anything (which you shouldnt be). How would your alk get that high? Until you have a bunch of corals or coraline algae sucking up those two your numbers shouldnt change a whole lot from the salt mix.

I don't trust Hagen test kits at all. I used their test kits when I first started in this hobby and they weren't great.

I have liked Salifert but would buy Elos if I needed new test kits.

What stores are using Hagen? Not a good choice IMO. I understand saving money but not at the expense of possibly ruining someone else's tank(s).

I will give a quick story of when I was helping a LFS.

We had a guy come in and told us he couldn't keep ANY coral alive. So I started asking about his setup and asked for all the details. He told me about his tank and about another LFS that was helping him out with his tank.

I asked about his water parameters. He said they were "fine" according to the other store. I then asked what "fine" meant. He had no clue and had no numbers to give me.

So he brought water in for me test another day. Alkalinity was well above 15 and calcium was around 700. I was SHOCKED and asked him if his tank had "snow" in it. He said when he dosed his product he got some of that "snow" I asked about. I asked him why he was dosing anything if he had no coral to uptake the supplements. His reply, "They told me I needed to add this stuff."

I told him to not touch a thing and do a large water change to help bring things in check. I also learned he had ZERO powerheads in his tank, only his two returns and they were doing about 900 gph on a 150 gallon tank. Yes, I was shocked.

After a few weeks he started adding coral and things were doing 100x better.

Moral of the story: Get your own tests and then compare them to the LFS. I am not saying to not trust our LFS. I love some of them. But as stated above, you will learn and care more about your tank then some random LFS employee.

That's why I love this group. We all have something to add which brings us to the answers best fitting the circumstances,  and with helpful stories too. Ya'll are awesome.

Rick you will get the hang of it after doing 10 times or so. You get to the point where you don't even have to look at the directions anymore lol

The first thing I would check is your Magnesium level. Magnesium is the component of the Holy Trio that helps maintain a balance between the three. I would guess if your having difficulty maintaining calcium levels your magnesium levels are also low. Shoot for a bout 1350 on the mag test.

Edited by bfessler - March 04 2011 at 6:47pm

Thanks you are the first to mention Mag.  I haven't been told by LFS or anyone else that it should or could be a problem,  I have an API test for that I will check it now, and post results soon.

What supplement do I need for Mag?

I know, but that is what I would have thought about calcium as well, yes/ no???