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No nitrates in a planted tank question

1930 Views 10 Replies 5 Participants Last post by  art_t
Sorry for a silly sounding question. I've tried to google this answer but I can't seem to find an answer to this question.

This is my first time having a planted tank (I had a non planted tank for 3 years prior to this). My new tank has been up and running for 5 weeks and it's planted w/ various swords, crypts & stem plants, all of which are growing very well. I'm dosing macro & micro nutrients (alternating 3 day macro, 3 day micro, flourish excel, saturday is no fert day). I have 6 angelfish in the tank which is 75g. I do a 30% pwc on Sunday. From the very beginning of setting up the tank I have never had nitrates. Every time I test for nitrates I get 0 ppm. So, is this normal with a planted tank, does having 0 nitrates effect a planted tank, and if yes in what ways? Does it mean that the tank is lacking something, or is 0 nitrates a good thing? Thank you for helping me understand this.
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This was very confusing for me at the start of my most recent tank. I had never had a plant focused tank before, and I kept measuring and measuring for nitrates. I don't measure ammonia or nitrites when I'm cycling, because it's a waste of time, IMO.

Long story short: This is normal. You are nitrate deficient. Whether that is a problem is another story, and is up to you on how much time, work and money you want to put into the tank.

My advice: Learn how to grow the plants you have. I skipped this step, and the learning curve I'm on is steeper than I expected.
If your plants are growing well and you have no algae issues, art, then more than likely either your nitrate test kit is faulty and giving you a reading that isn't showing the true nitrate level in your water, or you have the tank so perfectly balanced all the time that the exact amount of nitrates that your plant population, within the CO2 and lighting environment that they're in, is consuming, with thorough efficiency, all of the nitrates that you're putting into the tank and need no more than you're giving them. The second of these possibilities as highly unlikely so I wonder about your test kit's accuracy.
Thank you for your responses! I have used this particular nitrate test kit on my old tank which from time to time tested positive for nitrates (this was in the non planted tank). This is why I figured the test kit wasn't faulty. It's a dropper test kit by API. I also tried the stick test strips today and the nitrates on the stick test were barely detectable as well.

So, if I'm nitrate deficient will it show in the plants and in what way? Will nitrate deficiency have a bad effect on my fish? Today I noticed some green algae dots on the inside of the glass. It was hard to see, but they are beginning to show up.
Nitrate deficienfy is certainly no threat to fish at all. Plant do need it to photosynthesize, though. Take a look at these sites...they will give you relevant information regarding nitrogen (nitrate) deficiency:
What are your lights, what are you doing for CO2, and what are you dosing?
It could be that you are providing enough NO3, and your plants are taking it all in. Plants can absorb more nutrients than they actually need.
It is also possible your plants aren't getting enough, and will start developing deficiencies soon.

Also, what is your substrate?
Avi, thank you for the links!!! I will certainly do some reading.

Tank parameters are:
75g, 108 watts (I have 3 separate fluorescent light fixtures. 2 fixtures have T8 bulbs @ 5,000k, 1 fixture has T12 bulb at 6,500k).
Eco Complete substrate
Plants include amazon swords, red melon swords, red flame swords, bronze wendtii, florida sunset wendtii, hygro, tiger lotus bulbs, ludwigia repens, vallisneria, driftwood.
Ferts include: Macro on Sunday, Tue, Thurs, (I mixed dry ferts into distilled H2O as per PPS Pro instructions). Micro fert is regular flourish on Mon, Wed, Friday. Sunday through Friday I also dose Flourish Excel. Saturday is no fert day. I just started this schedule last week though.
No CO2 (although I have everything needed to do pressurized CO2 if and when I'm ready).

Thank you for helping me to understand this. So much needs to be considered w/ a planted tank. And I'm glad low nitrates won't effect my fish. If I HAD to choose between fish or plants, I would choose my fish. Their well being is my first concern.
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It really sounds like you should calibrate the test kit to see if it is working.'s just a matter of time before you figure it all out. Right now, your tank is doing well so I don't think there's anything to be alarmed about. Your light isn't very intense at approximately 1.4-watts per gallon so if your plants are doing well, then there isn't too much to hope for more than that. But, if your tank really doesn't have any available nitrates along with only 1.4-wpg you'll more than likely run into algae problems since the plants will start to slow down their growth and adventitious algaes can take a foothold. So, overall, I'd suggest that you get another nitrate test kit or at least bring a sample of your tank's water to a reliable local fish store and ask them to test your water for you.
PPS pro adds very low levels of nitrates, as does feeding the fish. It sounds like a good plan. As long as the plants appear healthy, I don't see any reason to change anything.
OK. Thank you for all your help. I'm not planning on changing anything but now I know I need to keep an eye out for algae. So, that's what I'll do. Thanks again!
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