ATI ICP-OES testing compared to my own testing
 

I just received my first analysis from ATI for my tank water and I did a complete test of my parameters using normal available test kits at the same moment I took the sample and sent it in.

What i have found is I am only really close in 2 parameters salinity and copper. Everything else is off and some by quite a bit.

Alkalinity I tested 8.4 with hanna and 8.5 with Salifert. The actual number was 8.1.

Calcium- I tested 430 with Salifert, 450 with Salifert Strontium test kit. The actual value was 409.

Phosphate ppm tested using hanna ULR at .043 actual was .01.

Nitrates using Red Sea Pro at 1.2ppm it was .01ppm

Mg tested using salifert ppm at 1500 actual is 1415ppm

K tested at 370ppm Salifert actual is 452.

Strontium tested at <3ppm with Salifert actual is 7.8ppm.

So based on my testing I was running GFO to lower phosphates and worried about my Magnesium being too high and my Strontium being too low. In the end ATI is recommending that I stop GFO add phosphate, iodine, molybedenum, Vandium, manganese and Floride everything else looks good. I also need to change my DI resin. Silicates are a little high

How do I trust my personal readings and make appropriate changes when the numbers are not even close? I have no reason to doubt ATI's numbers

And by the way copper was only close because both tested none. I believe the Salifert cu test kit is only really designed when treating parasites in a quarantine system. So that was a no brainer.

I chose ATI because from what I read and saw they appeared to be the best and they also test RO water as well.

Sending a sample in for testing is just the latest money making fad in our hobby IMPO. Once you get your results back you just end up 'chasing the numbers'.

Just my 2 cents.

Actually it is a lot more than 2 cents. I never used to do testing and would prefer not to.
Unfortunately in my large tank 75 gallon (set up for 3 years) alkalinity, calcium, phosphate and nitrates are incredibly variable and change quickly. When they change quickly my sps go into stress real fast. I have to test alkalinity and phosphate daily. Today my alkalinity could be 7.5 and tomorrow it could be 9.0.

I have to add nitrates to both balance the phosphates in the tank and to keep the corals from loosing colour. I have to monitor these numbers to keep things balanced.

I just want to make sure that what I am testing is actually what it really is.

I have a 35 gallon reef tank that has corals in it (LPS, SPS and zoas), has been set up for 15 years and now never has issues. I only test alkalinity and calcium once a month to make sure the amount of 2 part I add is correct. I rarely do water changes and the corals are doing great. I take out (sell) about 2 pounds of frogspawn a month from this tank. I test for nitrates and phosphates about once every 6 months and it is always exactly the same. .02 phosphates and 2.0 nitrates.

Every tank is different, this hobby is not a 1 system works for all and my tanks are the perfect example. Not really doing anything different in my tanks, feed the same equal number of corals and fish inch per gallon, same corals.

I have so much to say but so little time. Let's discuss at Macna.

Like I said its a lot more than 2 cents.

Glen, are you running dosers on your 75g?
Mine never fluctuates like yours, but I don't bother to test daily. I test weekly and adjust my timers accordingly and this keeps things stable.

I have a Kamoer doser but I haven't set it up. Currently I am dripping (Tunze auto top off) kalkwasser and supplementing with 2 part when necessary. My house is quite dry (air conditioner) and I lose a lot of water a day to evaporation and I can almost keep my levels correct with the kalkwasser.

Hmm. I'd get away from adding kalkwasser in conjunction with your ato, and I'd probably stop the kalk altogether. You don't need it. I've never used it.
It's too aggressive and hard on pumps.
This may be why your alk is swinging, because it's tied into your ato, which is not consistent.

Separate your ato from everything, remove the kalk, and start testing daily for Alk and Ca. Then you'll see some stabiblity and can move forward with your 2-part additives.
I bet you see stability and your dosing will balance out.

Then set up your doser and you'll be much happier with weekly testing.

Oh, and don't worry about the results you got back from ATI.
As long as you're close to the proper results with your kits, as I see you were, it's not worth worrying about. Your kits are doing just fine.

I think your Kalk addition is what's stressing out your corals as your ATO will fluctuate, so then will your Alk.

Only started adding Kalk in the past couple months or so because my phosphates and nitrates shot through the roof when my large yellow tang died and I couldn't find the body. I have been having stability issues for well over a year and a half basically since I started dosing nitrates.

I added the Kalk to help stabilize the phosphate. I didn't want to have to get too aggressive with the GFO.

I have added Kalk before without too much problem.

The purpose of this post was to show how imprecise the home test kits.

I know I have issues and I am working on efforts to stabilize my tank. But because I have issues the short term solution is to test the parameters and make adjustments daily.

I was hoping that my use of test kits was precise enough to give me a close enough reading. Apparently not.

Now there are multiple ICP companies has anyone checked ICP results from different companies? I would be interested to see how close they would be from a single tank all taken at the same time.

Your coral doesn't care if your test kit isnt accurate. All it cares about is stable parameters every day. If you test Ca at 405 every single day (whether it's a correct reading or not) and you repeat consistent testing methods, then your coral will be happy.

Consistency over accuracy.

Anything else is just chasing the numbers.

Agreed to a point, however what if the readings you are getting off your test kits changes each time you test. Today you test the alkalinity at 7.0 and tomorrow you test it at 8.5 but it is only test kit error and the true alkalinity didn't change.

I am only searching for stable values not overly concerned if my alkalinity is 7 or 8 but I don't want it jumping all over the place.

A year ago I found out that my 6 month old Sybon salinity calibration solution was way off. I thought my tank was at 1.025 and it was actually at 1.030.

Sending off the samples to ATI is just a way of finding out if my test kits are giving accurate numbers.

Fair enough but how can you be sure ATI's results are correct?

I never got variable results when I tested with Salifert for example.

From what I have read ATI (German) appears to be the best. Triton North America had some early user errors, Marin Lab (Poland) is OK and Coralvue (US) is not reliable.

I am really not sure that you can even compare hobby grade test kits, that are wrought with human error to lab grade ICP testing done by a knowledgeable lab technician.

From my experience with hobby grade test kits they tend to be relatively consistent if we take out the human error factor.

I just wanted to know how my readings compared to the lab testing. I also wanted to confirm that there were no unwanted substance (heavy metals etc.) that cannot be tested for.