Lab results compared with hobby test kits

[KSzegi]

On Monday I sent in my water sample to Aquarium Water Testing to be analyzed. I had done it since I was getting such vastly different nitrate readings on different kits that I wanted to see where I was truly at and perhaps which kit was most accurate. My tank is doing good but not quite thriving like I would like - seems like the growth has slowed and the colors aren't as good/vibrant as they were, have also noticed that the coralline growth has decreased markedly over the past couple months... and a few other 'minor' things that made me believe something was just not as good as it should be but unable to put my finger on it. Results have all been consistent with the kits I have. Here are the results from the lab I just received along with the levels that I tested immediately after mailing the samples off.

Water Test Summary
Ammonia (NH3-4) ........................Good ......................................... 0.000 didn't test
Nitrite (NO2)................................Good ......................................... 0.007 didn't test
Nitrate (NO3)...............................Good.............................................3.0 Red Sea Pro - 8, Salifert between the 10/25 colors closer to 25, API between the 20/40 closer to 20.
Phosphate (PO4) ..........................Good ........................................... 0.04 Hannah checker - 0
Silica (SiO2-3) .............................Good.............................................0.3 no test
Potassium (K) ...............................Low ............................................. 249 no test
Calcium (Ca) see note below .........Low ............................................. 171 sea chem - 455 api - 500
Molybdenum (Mo)......................... High.............................................. 0.6 no test
Strontium (Sr) ............................. High............................................ 16.3 no test
Magnesium (Mg) ..........................Good .......................................... 1213 salifert - 1450
Iodine (I ̄)................................... High............................................ 0.11 salifert - 0
Copper (Cu++) ............................Good ........................................... 0.03 no test
Alkalinity (meq/L)..........................Low ............................................ 2.00 hanna - 3.1 api 9(kh)
Boron (B) .....................................N/A ................................................. - no test


I'm rather surprised with some of the variance in results .... but it does make sense with what I am seeing in the tank. I'm not sure how to attack the issues at the moment, especially when the test results I'm getting at home may be considerably off. I understand that the total calcium concentration may be 20-30% higher than the 171 which represents the amount of free calcium - but even then it is too low, not even close to what it should be. I will be trying a couple other brands of test kits for comparison ....

Some of the levels such as the molybdenum really concern me ..... my level is significantly higher than the .12 mg/L that is the upper toxicity level. Since I use no additives that contain it, I can only think it was from the salt I was using - think I'm glad I made a switch. Interestingly, the lab notes that high levels are known to encourage blooms of slime algae and cyanobacteria - which I had been fighting. The strontium is also higher than it should be and again, I add nothing so can only blame it on the salt?

Anyway, I found the results to be very interesting and thought I would share them ....

 

[montethemoster]

Very interesting. Personally I am very surprised by the calcium portion of the test that is quite a big difference considering your kits show it being slightly higher than normal sea water. Thanks for posting the results.

 

[ErikRdz]

What salt do you use?

 

[Troylee]

Great thread!!! Thanks for sharing...

 

[WesF]

FWIW, there has been controversy in the past over Aquarium Water Testing and whether or not they provide accurate results.

 

[KSzegi]

Very interesting. Personally I am very surprised by the calcium portion of the test that is quite a big difference considering your kits show it being slightly higher than normal sea water. Thanks for posting the results.

I agree, the calcium was the biggest 'head scratcher' for me. The note on the test does indicate that their test is measuring only the amount of free calcium ions present .... and according to Randy Holmes Farley, the total calcium concentration can be 20%-30% higher. So .... I guess it is possible that the total calcium concentration would be closer to 300, though still far less than what is being measured by my tests. I will be receiving another test tomorow and will be curious to see what the results from that one are. As a side note, however, I used to test levels closer to 600+ and alk at 12 ..... where you would think there would be precipitation and there wasn't.... never had an issue...

What salt do you use?

I had been using coralife for the past2-2.5 years and just switched over to Red Sea Coral Pro - I had done only one water change at about 15% a few days prior to sending in the water samples.

Great thread!!! Thanks for sharing...

Glad to!

FWIW, there has been controversy in the past over Aquarium Water Testing and whether or not they provide accurate results.

Yes, I am aware that there had been some controversy about some of their results awhile ago, but do appreciate you saying something! And I'm certainly not saying that their results are the 'be all end all' ..... not ready to jump into any drastic changes based upon this one report anyway! But I also think that there is controversy about the results in many of the hobby grade test kits that we have available too (as well as so many things controversial in this hobby).... and am no more certain of their accuracy at this point. It is hard to put full confidence in them either when their results can be so drastically different between brands and even between two test kits of the same brand done by the same person. And how do we determine which is the accurate one?


I just know that their is a something rather subtle that isn't quite right with my tank so I was looking at this test as another tool to try to figure out what changes I could make. Based upon what I'm seeing in conjunction with the results, it does make some sense. I'm glad that I did switch salt mixes and feel that I can increase my 2 part dosing slowly without harm to see if raising the alk/calcium levels will make a positive difference. I will also be testing for potassium tomorrow, comparing results and feel that I can dose that, beginning in small increments.

Just thought the comparison might be of interest - and will post the results comparison after using the new test kits too.

 

[Troylee]

From what I recall most test kits are off in this hobby but there close enough to get us by.... I mean think about it lab grade test are bookoo bucks where getting these kits for a dime a dozen... It's the same deal with hydrometers etc... It's okay if there off as long as we're close and we keep it in that range wether its off or not stability is key and the corals will adapt...

 

[KSzegi]

From what I recall most test kits are off in this hobby but there close enough to get us by.... I mean think about it lab grade test are bookoo bucks where getting these kits for a dime a dozen... It's the same deal with hydrometers etc... It's okay if there off as long as we're close and we keep it in that range wether its off or not stability is key and the corals will adapt...

Oh, absolutely, I agree 100%. I really don't need to know the exact numbers ..... more important to monitor the stability and/or trends. However, when you run into the situation like I had with the nitrate for example ..... 8 -40 is a huge range on a rather important parameter..... my gut and tank said it was the 8 but for a relatively low price all things considered, it made me feel better to see what a lab test had to say.

 

[Young Frankenstein]

FWIW, there has been controversy in the past over Aquarium Water Testing and whether or not they provide accurate results.

Yes i also agree with that statement.

 

[Dog Boy Dave]

If you use the same brand test kit and look for consitency over a long period you will usually be ok. I compare my ApI alk and calcium results with historical readings and also with freshly mixed salt water. I have been using same kits and same salt and same 33 gallon trash cans for years. If my corals do well with an API test kit reading of 480 calcium and thats where it stays then I look elsewhere if i notice an issue. Doesnt really matter if it is really 480 as long as its consistent and the corals have done well in the past with that reading. Also remember, we have the best test kit nature can tailor right here in front of us. Your corals will tell you if something is wrong. If you pay attention, your experience will teach you to read the signs.

 

[fsu1dolfan]

Whether they are 100% accurate or not...still kind of cool to get all of your stuff measured. How much does this does this run?

EDIT:

Sorry lazy question - I googled it.

 

[flyfish4trout]

I briefly checked out this website and I thought it was curious that there is no test methodology described. For the price that they are charging I wonder if they are simply using test kits. Also, I am interested in how you preserved your sample for shipment to the laboratoy. For instance when I collect groundwater or surface water samples (I am an envrionmental consultant) I have to use certain preservatives for metals, VOCs etc. and then keep the water cooled to 4 degrees C or the lab will flag the samples. Is there any Quality Assurance Qualtiy Control (QA/QC) that was associated with the testing? It is an an interesting concept.

 

[KSzegi]

If you use the same brand test kit and look for consitency over a long period you will usually be ok. I compare my ApI alk and calcium results with historical readings and also with freshly mixed salt water. I have been using same kits and same salt and same 33 gallon trash cans for years. If my corals do well with an API test kit reading of 480 calcium and thats where it stays then I look elsewhere if i notice an issue. Doesnt really matter if it is really 480 as long as its consistent and the corals have done well in the past with that reading. Also remember, we have the best test kit nature can tailor right here in front of us. Your corals will tell you if something is wrong. If you pay attention, your experience will teach you to read the signs.

I agree - but my corals seem to be telling me that something isn't quite right and tests have been pretty darn consistent .... so I was just thinking that an outside lab test that included a few things that I dont/cant test for might give another clue since the issues are so subtle.... and maybe, just maybe ..... some help in deciding which test kit to stick with when they differ greatly in results.

I briefly checked out this website and I thought it was curious that there is no test methodology described. For the price that they are charging I wonder if they are simply using test kits. Also, I am interested in how you preserved your sample for shipment to the laboratoy. For instance when I collect groundwater or surface water samples (I am an envrionmental consultant) I have to use certain preservatives for metals, VOCs etc. and then keep the water cooled to 4 degrees C or the lab will flag the samples. Is there any Quality Assurance Qualtiy Control (QA/QC) that was associated with the testing? It is an an interesting concept.

Good point, and I may have to ask the lab that when I contact them regarding the test results. There was no special preservation whatsoever - simply filling two bottles (plastic) with tank water and priority mailing them back to the lab.




I also wanted say that I was not trying to advocate this lab and or testing, and by no means was I saying that the hobby kits were no good or not useful, I have depended upon them in the past and will continue to do so ...... I was simply sharing the results that I received, not trying to stir up any controversy!! :tongue1:

 

[flyfish4trout]

Thanks for taking the leap and keeping us updated on your findings. I am going to try to contact some test kit vendors to see how they test thier kits for accuracy and precission. Good luck with getting your tank back on track.

 

[caudill187]

Makes me wonder if some calcium and the ions measured by "alkalinity" may have precipitated in shipping? Awesome thread. Thanks.

 

[KSzegi]

Thanks for taking the leap and keeping us updated on your findings. I am going to try to contact some test kit vendors to see how they test thier kits for accuracy and precission. Good luck with getting your tank back on track.

I would be curious to know, please post back if you find anything out.

Makes me wonder if some calcium and the ions measured by "alkalinity" may have precipitated in shipping? Awesome thread. Thanks.

I really don't know if that would happen or not - right now I wish I had taken some additional samples at the same time and stored them for the 3 days even to test at home and see what the results would've been at that point sitting in plastic bottles and maybe thrown around in the box in the heat a bit to duplicate the postal shipping! LOL




I am actually considering using another Lab that does chemical anaylsis of marine water to perform some of the tests ....... they are considerably pricier - but have seen them recommended and my curiosity may get the better of me. I've also set a request to AWT for some insight on their testing methods and concerns that I have with the drastic differences in their results vs mine. Will be interesting to see how they respond.

 

[jdpiii3]

I sent in a sample of my water and wasn't happy with the results I received from AWT

Ammonia (NH3-4) ........................Good......................................... 0.000
Nitrite (NO2) ................................Good......................................... 0.006
Nitrate (NO3) ...............................Good............................................. 3.4
Phosphate (PO4) .......................... High............................................0.02
Silica (SiO2-3) .............................Good............................................. 0.2
Potassium (K) ...............................Low............................................. 257
Calcium (Ca) .................................Low............................................. 282
Molybdenum (Mo) ......................... Good.............................................0.1
Strontium (Sr) ............................. Good.............................................9.8
Magnesium (Mg) ..........................Good.......................................... 1150
Iodine (I¯)...................................High............................................0.15
Copper (Cu++) ............................Good........................................... 0.02
Alkalinity(meq/L) .......................... Low............................................4.30

So I sent in a sample of fresh salt water, and this was the result.

Fresh Batch of Kent Marine Reef Salt

Ammonia (NH3-4) ........................Good......................................... 0.000
Nitrite (NO2) ................................Good......................................... 0.000
Nitrate (NO3) ............................... Good.............................................1.4
Phosphate (PO4) ..........................High............................................0.00
Silica (SiO2-3) .............................Good............................................. 0.2
Potassium (K) ............................... Low.............................................346
Calcium (Ca) .................................Low............................................. 350
Molybdenum (Mo) ......................... Good.............................................0.1
Strontium (Sr) .............................Good............................................. 9.8
Magnesium (Mg) .......................... Good..........................................1350
Iodine (I¯)...................................High............................................0.15
Copper (Cu++) ............................Good........................................... 0.02
Alkalinity(meq/L) .......................... Low............................................5.30



Mix as per Kent Marine instructions

1.024-1.026 pH 8.3 to 8.3 Ca 550 - 575Mg 1350 – 1450 Kh 9.5

And these are the results I get when I use Salifert kits, I don't have kits for the other stuff.

NO3 0.0 -.2
PO4 0.0 -0.03
KH 9.3- 9.4
Mg 1450-1480
Ca 480-490

 

[KSzegi]

Thanks for sharing your results. Interesting to note that the calcium is low in all tests......

 

[eddiecorrea]

I'm gonna have to send out a sample. My tank is thriving but a test kit reads I have nitrite.

 

[VIPReef]

I would be concerned about evaporation during transit which would lead to higher test results. Are they bringing this test water back to normal salinity ratios before testing? i'm not really familiar with the company, but if their sole purpose is to test "aquarium" water why are their number so off?