High NO3 and hardness - The Planted Tank Forum
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post #1 of 7 (permalink) Old 11-23-2014, 11:22 PM Thread Starter
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High NO3 and hardness

Three weeks after tearing down and reconfiguring a standard 55 gallon tank, I get the following:
NO3: 200
NO2: 0
pH: 7.0
kH: 100-120
GH: 180
These readings are from API 5-in-1 Test Strips.

I re-used much of the water from before the tear-down. Also reused the filter media for the two HOB filters, and the Flourite substrate. I added a 1-inch layer of topsoil below a 1-inch layer of Flourite. I boiled the topsoil for 15 minutes, and strained out as much of the large bark, wood, etc. as possible. I also added a dose of phosphate-free Tetra FloraPride right after set-up, and no ferts at all since. I dose 5 ml of API CO2 Booster daily.

Fish load is moderate: 4 rosy barbs, 4 bronze cories, 2 SAEs, 6 guppies.
Plant load is also moderate: 70% of the substrate is covered with red myrio, Indian Red Sword, Anubias Congensis, java fern, water sprite, and assorted grass types.
Lighting is two 6500 HO T5 bulbs, full length of the tank, on a timer to be on for 10 hours a day. I have another fixture with regular (non-HO) T5s, but I don't have it turned on at all now.

A week after the re-set-up, I had a green water outbreak starting, so I have been running a UV light on the timer with the lights (10 hours a day).

Everything seems to be going well with fish and plants, but the NO3 levels and the GH seem very high. I generally top-off with distilled water because my tap water has the same hardness (both KH and GH) and a pH of 7.5-8.0.

I've had tanks for years, usually with some easy plants, but this is the first time I'm trying to do a "real" planted tank. So I have questions about the water quality.

Should I be trying to lower the hardness, or just leave it alone? Is the high NO3 because of the soil in the substrate? Anything to worry about? What other parameters should I be testing for? The new leaves on the swords are coming in red, but the new growth on the myrio is green. Should I add more light (easy to do; I could just run the other fixture on the same timer)? Turn off the UV light? Seems like it would interfere with establishing proper bacterial activity?

Last edited by LRM2; 11-24-2014 at 12:02 AM. Reason: adding additional information
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post #2 of 7 (permalink) Old 11-24-2014, 12:36 AM
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I've got water with really high gh and kh as well. I wouldn't try lowering it. Unless you want to mess with RO water or install a water softener, I have found it best to just work with it. A lot of plants will grow in hard water as well as some beautiful fish and shrimp (Celestial Pear Danios, rilli shrimp).

Last edited by fish878; 11-24-2014 at 12:58 AM. Reason: spelling
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post #3 of 7 (permalink) Old 11-24-2014, 01:37 AM
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A water change of less than 50% will only drop the NO3 less than half.
So at least 50% is used when doing a water change specifically for high nitrates.
The dirt will cause that but so will using sub that you just stirred up
and moved to another tank. If it stays high(when tested after 24 hrs after the WC)then likely it is the dirt.
If so it will stop after a couple or a few weeks. Till then I'd try to keep it under 100 via water changes. But put some of your tap water in an open bucket over night and check it for NO3.

The shortest distance between any two points is a straight line...in the opposite direction...
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post #4 of 7 (permalink) Old 11-24-2014, 01:08 PM
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1) Check tap water for NO3.
2) Do plenty of water changes with water that has the same hardness as the tank. The fish are acclimated to that level of minerals, and any change needs to be done gradually. Get the NO3 significantly lower, then deal with the GH and KH if you really need to.

The GH is fine for most community fish that have been bred in captivity, and very good for live bearers and many Rainbow fish.
If you are trying to keep or breed wild caught soft water fish then it is way too high.
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post #5 of 7 (permalink) Old 11-24-2014, 02:16 PM
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+1 to all above..

Also, if you haven't already.. test your nitrate test.. these are notorious for not being well calibrated to their color charts. (One of mine reads about 6x higher than actual)
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post #6 of 7 (permalink) Old 11-24-2014, 05:30 PM Thread Starter
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Thanks for all the suggestions! I am suspicious of the NO3 result because the fish show no signs of distress whatsoever. I think I'll get a stand-alone nitrate test kit and see what it says. In the meantime, I'll keep doing water changes.
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post #7 of 7 (permalink) Old 11-24-2014, 06:16 PM
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If you have some KNO3 and distilled water, you can make a calibration solution with known PPM and use that to calibrate the test... I believe the ferts & water parameters board has a sticky linking the recipes...
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