Why don't I have nitrates?

[Venom_]

I have 36g tank with 7 black neon tetras, 7 neon tetras, and 3 Apistogramma. I have to aquaclear 50 running full time and I only use RO water with a little bit of tap water to do my water changes every week . My tank has been running for almost 3 months so it already established and ammo and nitries are at 0. At first I had some nitrates but now every time I test nitrates before a water change I have no nitrates. I once went on vacation a didn't do a water change for 2 weeks and still had no nitrates...why?

 

[Stefernini]

That is generally a sign that the tank is not actually cycled. What test kit are you using? The liquid API kit, or test strips? Strips can give you false readings. Also, how are you handling your filter media? Are you changing it out every time you do a water change, or are you rinsing it in treated water and putting it back? If you are changing it out, you aren't letting the bacteria grow and that could keep you perpetually cycling. You should rinse it and put it back until it's falling apart, then put in new.

Also, if you are using the API test kit, are you following the instructions correctly for testing nitrates? You've really got to shake that bottle really, really well.

 

[Venom_]

I use the API liquid test. I make sure I shake it good and follow instructions every time. It is not expired nor defective. I never rinse my bio media I just leave it in the filter but I do rinse my sponges. I rinse them in a bucket with the water I take out of my tank to make sure the bacteria doesn't die.

 

[Stefernini]

Maybe you are just doing an awesome job on the water changes then? You're under stocked, only about 70% I think. How big of a water change are you doing each week?

 

[Venom_]

Yea maybe it's just weird and I change 5 gallons every week.

 

[BBradbury]

Your Tank

I have 36g tank with 7 black neon tetras, 7 neon tetras, and 3 Apistogramma. I have to aquaclear 50 running full time and I only use RO water with a little bit of tap water to do my water changes every week . My tank has been running for almost 3 months so it already established and ammo and nitries are at 0. At first I had some nitrates but now every time I test nitrates before a water change I have no nitrates. I once went on vacation a didn't do a water change for 2 weeks and still had no nitrates...why?

Hello Ven...

I'd say the water problem may be with the RO water. You really should be using treated tap water if at all possible. Tap water replenishes minerals, especially calcium, a nutrient needed for both fish and plants. The minerals from public water supplies helps maintain a steady water chemistry including pH levels.

Sterilized water contains no buffers, so you're likely to get swings in the water chemistry, which usually doesn't do the fish or plants much good.

I'd suggest large, frequent water changes with pure, treated tap water. Tanks less than 38 gallons required 50 percent water changes weekly to maintain safe water conditions. The larger tanks can typically go a couple of weeks between large water changes.

Just a suggestion. You're the head waterkeeper.

B

 

[Stefernini]

It is weird, usually there's at least a little. Even my 10 gallon with a loan betta in it gets up to at least 5ppm, sometimes 10, by the time I do another wc.

 

[Venom_]

Hello Ven...



I'd say the water problem may be with the RO water. You really should be using treated tap water if at all possible. Tap water replenishes minerals, especially calcium, a nutrient needed for both fish and plants. The minerals from public water supplies helps maintain a steady water chemistry including pH levels.



Sterilized water contains no buffers, so you're likely to get swings in the water chemistry, which usually doesn't do the fish or plants much good.



I'd suggest large, frequent water changes with pure, treated tap water. Tanks less than 38 gallons required 50 percent water changes weekly to maintain safe water conditions. The larger tanks can typically go a couple of weeks between large water changes.



Just a suggestion. You're the head waterkeeper.



B

I should add that i tried to create a black water South American biotope and I use RO water to replicate the soft water and ph. I add about a cup of tap water for each gallon of RO water. I have a Indian almond leaves that leach out tannins and heard that the leaves are good for the fishes health and provide minerals and nutrients, is that true?

 

[Mebbid]

What's your ph at?

 

[Venom_]

What's your ph at?

About around 6.6

 

[Mebbid]

About around 6.6

You should still be processing ammonia at that level. Like BBradbury said though, there's no buffers which can cause pH swings. If the pH drops below 6.4 then all processing of ammonia stops. However, if you were getting a reading of 0 on nitrates due to the ammonia not being processed / the tank not being cycled you would have a positive reading of either nitrite or ammonia. Following a 0 reading on either of those then I would say that it's most likely a mistake with the testing procedure itself. Maybe you're missing a single step with the test? Just be sure to follow the directions to the letter when doing the nitrate test and if it still reads 0 then I would say get a second opinion and have a LFS test it.

 

[Venom_]

Ok when I get home I will test ammonia, nitrite, and nitrates. I think I have slight ph swings but I'm not sure. Would these ph swings occur randomly or in a pattern?

 

[Mebbid]

Ok when I get home I will test ammonia, nitrite, and nitrates. I think I have slight ph swings but I'm not sure. Would these ph swings occur randomly or in a pattern?

The pH would go down overnight and then back up throughout the day. Photosynthetic organisms will put out CO2 at night which is acidic and has the effect of lowering the water pH. During the day the opposite happens and co2 will drop bringing the pH back up.

 

[ArtistGardener]

Is this a planted tank? If so, how heavily?

 

[Venom_]

Just tested my water.
Ammonia 0
Nitrite 0
Nitrate 0
I haven't done a water change in 1 week and 3 days. Shook those nitrate bottles pretty hard this time and still no nitrates.
My tank has no plants in and barley has any algae. I would like to add like 2 Amazon swords and amazon frog bit when I get my t5 HO light, but not sure how they would do.
Here's a pic of my tank right now.

 

[ArtistGardener]

Hmm… I am not familiar with any variables related to low pH water since mine is very hard and high in pH. BBradbury and Mebbid's point about pH swings and necessary elements is important since you have almost no buffering capacity--pay attention to that advice. Depending on your local water source, the small amount of tap you are adding may not have enough buffering elements or electrolytes for a safe and stable tank.

If there are no living plants at all, then I would say your test is bad or you still aren't agitating bottle number 2 well enough. Bang that sucker hard on the countertop several times in addition to shaking the living daylights out of it. If you are still getting a zero reading, do take a sample into your LFS for a test.

Good luck. It is an interesting start to a tank. Out of curiosity, how did you cycle this tank? Fishless or fish-in? Did you have the ammonia, nitrite, nitrate spikes earlier?

 

[Gillie]

Definitely add more tap water and look into a tds meter. I'm trying to figure out how to link a bunch of info that is greatly useful when trying to match water parameters for a blackwater biotope.

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[Gillie]

http://www.plecoplanet.com/forum/showthread.php?t=3480

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