# [Wet Thumb Forum]-Trouble with nitrate test readings



## lsuber (Dec 15, 2003)

I'm having trouble determining my nitrate level, and will post as much info as I can think of. I'm using a Red Sea NO3 test kit that arrived today. The tank is a 90-gal tank, and I'm using potassium nitrate and potassium sulphate purchased from www.plantgeek.net. I added 1tsp of KNO3 and 2tsp of K2SO4, waited one hour, and tested with the kit. It read zero (remained a very pale, light blue color). I added another tsp. of KNO3, waited another hour, retested, and obtained the same result. One thing I notice about the test kit, is that Reagent A seems to have a dark precipitate in the bottom of the bottle, even after shaking vigorously. According to Chuck's Planted Aquarium Calculator, a total of 2tsp. of KNO3 into 90gal should have resulted in around 12ppm of NO3, yet I continue to read zero. I have a cheap bottle of Jungle Nitrate/Nitrite strips that I will try later to see if get any reading with it. Any thoughts as to why this is happening? My tank is currently at 82F, and has been completely planted for about 10 days. Mostly fast growing stem plants (anacharis, hygro, rotala). Thanks for any help anybody can pass along.

Update: After reading with the Jungle test strip, the nitrate pad developed a color between the 20 and 40 levels, indicating nitrate in the tank. I assume the Red Sea test kit is bad. Can anybody confirm for me the presence or absence of a black precipitate in the A bottle?

[This message was edited by lsuber on Fri February 13 2004 at 06:46 PM.]


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## lsuber (Dec 15, 2003)

I'm having trouble determining my nitrate level, and will post as much info as I can think of. I'm using a Red Sea NO3 test kit that arrived today. The tank is a 90-gal tank, and I'm using potassium nitrate and potassium sulphate purchased from www.plantgeek.net. I added 1tsp of KNO3 and 2tsp of K2SO4, waited one hour, and tested with the kit. It read zero (remained a very pale, light blue color). I added another tsp. of KNO3, waited another hour, retested, and obtained the same result. One thing I notice about the test kit, is that Reagent A seems to have a dark precipitate in the bottom of the bottle, even after shaking vigorously. According to Chuck's Planted Aquarium Calculator, a total of 2tsp. of KNO3 into 90gal should have resulted in around 12ppm of NO3, yet I continue to read zero. I have a cheap bottle of Jungle Nitrate/Nitrite strips that I will try later to see if get any reading with it. Any thoughts as to why this is happening? My tank is currently at 82F, and has been completely planted for about 10 days. Mostly fast growing stem plants (anacharis, hygro, rotala). Thanks for any help anybody can pass along.

Update: After reading with the Jungle test strip, the nitrate pad developed a color between the 20 and 40 levels, indicating nitrate in the tank. I assume the Red Sea test kit is bad. Can anybody confirm for me the presence or absence of a black precipitate in the A bottle?

[This message was edited by lsuber on Fri February 13 2004 at 06:46 PM.]


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## Verminaard (Dec 18, 2003)

Wait it out. I have had the same problem in the past. In my experience you need to wait 12-24 hrs before an accurate reading can be made. I have made the misake of over dosing no3 based on faulty readings. Trust me wait until tomorrow morning and you will have your readings. I have a red sea no3 kit and mine had a dark precipitate as well.


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## Chousal (Feb 8, 2004)

I had trouble with Sea Red Fe test, I'll never buy Sea Red Products.

Saludos...

Acuariofilia most not be costly.


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## Rex Grigg (Jan 22, 2004)

First off, NEVER TEST YOUR TEST KIT IN YOUR TANK! Second your math is wrong. Two teaspoons of KNO3 in a 90 gallon tank gives 19.77 ppm of nitrate according to Chuck's calculator.

If you were driving down the freeway and your speedometer said you were doing 25 mph but you were passing all the other cars like they were standing still would you attempt to accelerate to get your car up to the speed limit? This is the same as testing your test kit in your tank. Always have an idea of how much of something you should have to add to get to the desired levels. Once you add that amount if the test kit registers a lower level first check your math, then check your test kit outside of the tank

Now, what I want you to do is take a bucket and dose the bucket. Then test the water. Also make sure you are shaking the regents and test vial as directed.

Chousal, iron test kits in general are pretty much worthless.










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## EDGE (Feb 28, 2004)

Rex reply gets more funnier to read each time.

---------------------------
My 75 Gallon

Aquabay


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## Planted Engineer (Jan 15, 2004)

Hi,

I had the same trouble with Red-Sea NO3 test kit. Not sure about the reagent - but it said 0 nitrates. I remember also trying to use their Fe or PO4 test kits - 0 reading as well. I switched to JBL and the results make sense. Not sure about PO4 of JBL but will check it soon. Anyway - I am not going to buy Red-Sea test kits, never ever again.

And to be on the safe side I will try to find Hach or LaMotte PO4 and NO3.

PE.


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## MarcinB (Apr 16, 2004)

I use JBL phosphate kit and IMO it's very accurate, at least in 0,5-1ppm range. I tested it against standard solutions prepared in a laboratory.

150L (40G) planted tank
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Rate my tank!


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## lsuber (Dec 15, 2003)

Thanks for the responses guys. My math actually wasn't wrong, Rex, my literacy was. I selected K in KNO3 and not N in KNO3. Oops. And I don't view a little higher than suggested nitrate level as analogous to driving 170mph on the highway, but your point's taken. Reagents and vials are all shaken as directed, etc. etc. I work in a medical laboratory and have quite a good grasp on proper procedure and reagent handling. And Edge, I'm not sure funny is the adjective I'd choose or not!

I do notice more than one reply stating dissatisfaction with the Red Sea kit, which is significant. I'll try mine again to see if it registers the predicted amount, either in the tank or in a dosed bucket (at this point, the nitrate is unmistakenly in the tank, so what's the difference???) I'll post back here with results for those who are interested! Thanks guys.

UPDATE: After retesting with the Red Sea kit, I still get a reading of zero. Using the Jungle nitrite/nitrate test strips, I get a reading of 40, which is exactly where the level should have been based on the aquarium calculator. I tend to think the Jungle test is correct, and the Red Sea is somehow faulty based on the fact that we KNOW how much nitrate is in the tank. Or, to use the highway analogy, our "pace car" (Jungle Test strip) is reading 40ppm, while our test car show zero. We clearly should be "in motion!!!!!"

[This message was edited by lsuber on Sat February 14 2004 at 06:47 AM.]


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## Garmoni (Dec 24, 2003)

I’m having similar problems with a newly purchased Red Sea nitrate test and want to prepare a controlled sample to test the kit. Tell me if I’m thinking through this correctly. I have a product (Kent’s Botanica Nitro+) that advises 1 ml of the product contains 44.2 mg of nitrate. If I add 1 ml of this to a gallon of water the kit should test 11.69 ppm.

I’m basing this on the following. One ppm is one mg per liter. One gallon of water is 3.78 liters. If I add 1 ml of this product, that contains 44.2 mg of nitrate, to one gallon of water it should test 11.69ppm (44.2/3.78). 

Is this correct or has the metric system claimed another victim.


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## Southrock (Feb 3, 2003)

Speaking as a victim of the metric sysytem, your math looks pretty good to me! I used (past tense) a Hagen NO3 test kit, which also seemed pretty worthless. I've been kicking around the idea of shelling out the big bucks for a LaMotte kit, but I might have to try the Jungle test strips first!

-SR


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## lsuber (Dec 15, 2003)

The Jungle test strips are certainly the cheapo of the testing world, but at this point is the one that's working for me. Using the Planted Aquarium Calculator, I know exactly how much to add to the tank to acheive a level of 10ppm when the tank is at zero. My problem will be determining where my level is mid-way through the week, and knowing how much to add to regain a level of 10. The test stip begins at 10 and goes up from there. 

I'm still puzzled as to why the Red Sea kit won't register anything when the tank undoubtedly contains 20ppm of nitrate. If it were a non-planted tank that I was measuring the end of product of fish waste with no knowledge of the expected result, it would be different. Knowing the result and still obtaining a reading of zero after carefully following all directions is a big failure on the test kit's part. I will give it another 12 hours like Verminaard suggested to take a final reading with that kit, and then it's being returned. It's curious to me as to why the cheap test strips immediately give a good reading of what was added, and the "better" kit takes 24 hours. Regardless of the outcome, I'm not impressed with the Red Sea product, and likely will return it for a different manufacturer.


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## Garmoni (Dec 24, 2003)

I think you need to be careful with the test strips also. I have the Mardel strips and they seem to read 20 ppm of NO3 regardless of the level in the tank. I get 20ppm readings before and after dosing with those things. I will use both test later this afternoon on the controlled sample I prepared and let you know what they read.


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## Rex Grigg (Jan 22, 2004)

It's possible that even though you just purchased the test kit that it could be expired. I have found that if you contact Red Sea that they will normally send you a new test kit or new reagents.










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## dennis (Mar 1, 2004)

Garmoni, 
One thing to watch out for is that some commercial ferts use and list NITROGEN(N) not NITRATE(NO3). I do not know if this is true of the Kent's product or not but is something you should be aware of. Other than that your math should be correct. Double check with a calculator to be sure though. Luck!

Dennis Dietz

http://webpages.charter.net/dennisdietz/Aquatic%20Endeavors.html


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## mm12463 (Mar 5, 2004)

I use the Kent's Botanica products right now. The Nitro+ bottle lists the source as Sodium Nitrate which is NaNO3 I think.

Your math is right.

I just did a test with a gallon of water and my Red Sea test kit, which I have never done before. Figured what the heck - lets see if this works.

So I tested the water from my tap first. It read 0. I then added 1 mL of Botanica Nitro+ which should read 11.69 ppm. It read zero.

I'll let it sit until tomorrow and test again.

I always get readings in my tanks from the Red Sea kit. From 0 to 10. Depending on when I dose and test. So far nothing has seemed illogical.

Now if Kent's would just fricken give me some answers to my emails on the K bottle I might keep using the products.

Mike
http://fish.silver-fox.us


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## Garmoni (Dec 24, 2003)

Well the results are in. I was expecting a reading of 11.69 and neither of my test kits tested accurately. The strip test gave a result of 20ppm, as I figured it would, and the Red Sea kit tested between 0 and 2.5ppm. Guess I will start looking into getting it replaced.

It’s cold here in Columbus and I know this kit sat on the UPS truck for two days before it was delivered. Does anyone think that could have somehow messed it up.

mm12463, Let us know what kind of result you get after letting your sample sit for a day.


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## lsuber (Dec 15, 2003)

It sounds more and more like the Red Sea stuff is junk. I don't care if it works in a bucket or not!!!! It needs to accurately measure nitrates in my tank to be of any value. I bought mine from Petsolutions, and I wonder if they'll credit me for it, or ship out a replacement. I'm really not too interested in another Red Sea product. I have a phosphate kit from them as well, and am wondering if it's of any use.


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## Garmoni (Dec 24, 2003)

I’m not going to write of Red Sea until I see how they deal with my defective kit. From what I read in this forum many people use these kits with fairly accurate results. Guess it’s possible that that we were shipped old kits or something. It’s interesting that there is a place on the bottom of the box for an expiration date but the kit I received does not have a date stamped in the box. I bought mine from marinedepot. I’m going to start by calling them and see where it goes.


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## Roger Miller (Jun 19, 2004)

I finally decided that I depended a lot on my occasional nitrate tests to measure the nutrient status in my tanks. I can't get by with a maybe-it's-right-maybe-it-isn't cheap test kit so I bought a good kit from Hach. I can't stand the case where my plants seem to be telling me one thing and my test tells me something else. With the Hach kit if the test result disputes my observations then I know it's my observations that need work. I should get the thing some time next week.

Roger Miller

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_"The indispensible first step to getting the things you want out of life is this: Decide what you want" -- Ben Stein_


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## Garmoni (Dec 24, 2003)

Roger, Do you mind me asking how much you paid for the good Hach kit and where you got it. I’m starting to wonder if I could have bought a good kit with the money I have spent on all of these cheap ones.


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## Roger Miller (Jun 19, 2004)

The kit was $52 plus shipping for a total of $63. It tests nitrate-N in two ranges; 0-1 and 0-10 and uses a color-wheel comparator. It's good for 50 tests, so the costs comes out to $1.26 per test. It's' a dry reagent kit, so the shelf life is long enough that I should be able to use all 50 tests.

I ordered online directly from Hach (www.hach.com). The site is not the easiest to use but it works.

Roger Miller

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_"The indispensible first step to getting the things you want out of life is this: Decide what you want" -- Ben Stein_


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## Hawkeye (Aug 20, 2004)

I use the Seachem line. Nitrate/Nitrite and Phosphate kits. I test 5 tanks at a time and can test them all at one time. I haven't had any trouble at all. They cost 9.99 each. You get 75 test per kit.

Hawk

Trust But Verify «*»®


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## mm12463 (Mar 5, 2004)

Well I tested my 1 gallon bucket of water after I dosed it with 11 or so ppm of Botanica Nitro. Read zipo. But I can test my tanks and get readings.

Like I said before when I dose and check a day later everything seems to read correctly. For example I test and I am at 2.5 ppm. I dose to bring it up to 10. The next evening it might be down to 5 ppm. So either the plants are using it or my test is wacky. Things seem to be growing fine.

I don't know what to think really. Am I smoking crack or something? I don't get it.

Mike
http://fish.silver-fox.us


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## lsuber (Dec 15, 2003)

I talked to the tech. person at Red Sea (I got the impression there is only one!) and she was very nice. She is mailing out a replacement kit for me, which I will try since it's free. I'm hoping I just got a bad one and that the new one will work as I'd hoped. I'll post my results here (if the thread is still here after a week's time). I may also get a SeaChem kit for comparison's sake.


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## mm12463 (Mar 5, 2004)

I purchased a new Red Sea NO3 kit today. I ran out testing that bucket. One thing I noticed today was bottle A was milky white in color and the new kit it is clear.

This time I tested the bucket that has been sitting for a few days now with a dose of 11pm Botanica Nitro. It worked. The color is closest to the 10 on the chart.

On a side note, if you are using the Botanica K bottle here is the info I was sent to today after I asked how much each ml adds. Unlike the Nitro+ and Phos+ it does not have this info.

_Botanica K contains approximately 5% KO2 (4.2% K). One ml of the solution contains approximately 42 mg of potassium, then. If adding this volume of Botanica K to 10 gallons of water (37.85 L), the overall concentration of potassium in the resulting solution would be approximately 1.1 mg/L._

So that is helpful. Really makes the directions on the bottle worthless. 1 ml per 10 gallons each week.

Mike
http://fish.silver-fox.us


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## Garmoni (Dec 24, 2003)

Well I called Red Sea yesterday also. Had a similar experience. The individual I spoke to was very helpful and offered to send a new kit with no questions asked. I think the defective kit I received was probably expired or went bad sitting on the UPS truck for a few days in freezing cold temps. The individual I spoke to mentioned that extreme temperatures could impact the kits. For those of you that have the Red Sea kits there is an expiration date stamped on the bottom of the kit. You have to look very hard in the proper light to see the indentation. I can’t completely make the numbers out on the bad kit I have. Will have to see what happens with the new kit that is on its way.

Mike, Thanks for the information on the Botonica K. I have been using it and that detail will be very helpful.


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## linklemming (Feb 10, 2004)

I have also had problems with my Red Sea NO3 test. There is a spot of black precipitate in my solution A as well which does not completly go away. I have made test solutions of 0,5,10,15,20ppm NO3 etc and all read between 0 and 2.5ppm. Unfortunately I assumed this test was reading corectly and have been dosing KNO3 excessively which have caused unwanted algae....causing me to try actually verifying the kit.

I have used Seachems NO3 test for years and never had this problem...even though they are several years old.

I just decided to go with a Lamotte kit. While the initial price is high, refills seem reasonable.

Gary


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## Garmoni (Dec 24, 2003)

I received my replacement Red Sea kit and have put it through several controlled testes. It seems to be reading correctly. I think it is safe to say that the first kit I received was expired or damaged due to freezing temperatures during shipping. The problem I’m having now is that I find it difficult to analyze the different shades of red and pink. 

For those of you that have the Seachem nitrate test do you find the color chart is easy to read or do you find yourself guessing at different shades of similar colors.


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## mm12463 (Mar 5, 2004)

0-5 are pretty easy. 10-20 is tough to red.
I think I might try the Seachem line when I run out. To bad some can't come up with an electronic gadget to read NO3 and PO4 that was seasonably priced. Hehehe.

Mike
http://fish.silver-fox.us


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## Rex Grigg (Jan 22, 2004)

There is an electronic gadget that will read NO3 and PO4, but of course it's not reasonably priced at around $800-$1000.










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