Bad Nitrate Test Kit? - The Planted Tank Forum
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post #1 of 3 (permalink) Old 04-17-2018, 02:54 PM Thread Starter
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Bad Nitrate Test Kit?

Bought a new API master test kit because mine was older than the hills. Expiration dates are good.

I have really, really soft water. Like melting snow soft. It's a shallow dug well in my basement. I was getting the odd waffling that low calcium brings and was waiting until my retirement check landed to buy more. Had a bag of organic garden lime to hold things at bay a bit. Color was good on the plants and they were growing fast in spite of the Ca/Mg shortage. The garden lime helps but it's pretty slow dissolving.

Noticed the deficiency getting worse so I broke down and bought some Equilibrium at the lfs. Took silly amounts of it to get GH up to 3. Waited a day and threw another spoonful in because the plants were hungry. I'm now at a GH of 4.

pH is maybe 6.6 or 6.8

pH on a cup of water from the tap, left out all night is unreadable. Just the slightest tinge of yellow.

Nitrate test developed into a deep red. This shocked me. I had just done a better than 50% water change and hadn't added anything beyond the Equilibrium. Tested again got the same. So didn't put any KNO3 in. Next morning the plants all looked pale, color fading. Test again. Again red, red, red. Yes I did shake and smack and shake the #2 bottle again and again.

Test some water straight from the tap, deep red. Water from aged cup is dark red too.

The tiny, pale new growth and fading older leaves made me suspicious so I added KNO3 like I've done for years. If anything I'm stingy because I don't have a good measuring spoon. That was only last night but it seems like a blush of color is appearing on the newest growth.

Disbelief made me just check again, dark red.

Tank is 75 gallons.
Pressurized CO2
light is an odyssea quad T5HO so it has more than enough light for the plants I grow.

None of the livestock show stress. Tank doesn't have a lot of fish. I have no nearby neighbors. It is possible this time of year that a little surface water got into my well but it would be surface water that just rained down or melted in an area that hasn't seen livestock in 100 yrs. If the test showed me 5ppm I might have believed it. Off the charts is something else.

Getting the same thing in my guppy tank only less pronounced. 29g with a lot more fish (guppies doing guppy things).

Am I correct in thinking my Nitrate test kit is garbage?

Ignore the calcium waffles. Got that covered.

I see algae sprouting that wasn't really there a couple of days ago too. Ugh!
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post #2 of 3 (permalink) Old 04-17-2018, 03:33 PM
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This will open a can of worms!! But then I'm saying it anyway! Old discussion but I feel there are water situations where the API kit does not work. Nothing personal against any of the products or companies but in my tanks and my water, the API nitrate test does no good once I get beyond about 20 PPM as it goes to totally red (burgundy?) color. Like you, I shook, bought new kits and even went so far as converting a reciprocating saw to make a bottle shaker. I did the try of "calibrate the kit" and when I tested 5 and 10 PPM it worked but went crazy with 25PPM.
I hate to overpay for any product but the solution, for me, was to buy the slightly higher priced Salifert nitrate kit but it DOES give me real answers that let me see a change when I do a 50 % water change.
So I now pay the premium price but look at it this way.
Is it more frugal to pay for tests which are cheap but mean nothing or to pay higher for actual results?
I suggest considering a kit change if all else has been tried.
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post #3 of 3 (permalink) Old 04-17-2018, 05:19 PM Thread Starter
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I was a little freaked out by the possibility that I was drinking and bathing in some nasty water. Just ran to the store and got a bottle of Poland Spring natural spring water because I could see the water report online.

tested that and got red. Not as dark as the tank water but still red.

Not that it means much but this water pretty much tastes like what I have at the house and is pretty typical of the water around here.
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