Re: [APD] RE: high NO3

["Tomoko Schum" <tomokoschum at knology_net>]

Thank you, Scott and Tom, for responding to my question very quickly.

> It is important to make certain the CO2 is good and double check the GH/KH

CO2 is up high right around 35 ppm or even a bit higher at times.  My KH is 
about 6 and pH is around 6.7.
I always clean my Eheim media with tank water (every two months.)  Ehfimech 
and Ehfisubstrat are stained (light brown) but they are holding their shapes 
well.  I vacuum substrate, but I have not done the deep cleaning like you 
suggest.  I will definitely try that.

> Now my question is also this: why are you using the test kit rather than
> your eyes to gauge the tank's need?

Ha, ha, you are sharp as a tack.  You got me on this one.  Actually I do not 
use any test kit except when I encounter a puzzling problem.  I took a 
nitrate reading because of one of these puzzling incidents.  However, it got 
even more puzzling because of the test results.

My puzzle actually started with some new plants.  A couple of local 
hobbyists gave me some plants that I have not kept before.  Among those are 
Potamogeton (Eustralis) stellata and a Lymnophila aromatica look-a-like (no 
detectable scent), which quickly grew into massive bushes.  All other 
plants, which I had for quite some time, started growing really slowly. 
Obviously these new plants are more demanding than my old common run of the 
mill plants.

Then the other new plant, Heteranthera zostifolia, started showing a symptom 
of potassium deficiency.  Since I saw a few pin holes on old leaves of 
Lysimachia (which I have known as a good indicator of potassium deficiency), 
I increased K2SO4 dosage.  Heteranthera zostifolia recovered, but things got 
tricky thereafter.

The tank now looked like it needed more nitrate, possible others as well.  I 
thought about increasing nitrate and phosphate along with potassium now that 
I seem to have a lot of more demanding/hungry plants.  But just in case, I 
tested the water for nitrate and phosphate.  I thought a baseline data would 
be good to have.  To my surprize, nitrate level was really high (over 40 
ppm.)  I did a really big water change (80% or so), cleaned my Eheim 
including two hoses, and vacuumed my substrate using Python (not as deeply 
as I should have).  I took another NO3 reading in a day or so, and it was 
still 30 ppm or higher.  So I reduced KNO3 dosage.  My NO3 test result was 
still at 30 ppm or so.  So I decided to go without dosing nitrate for a week 
to see if this make any difference.  Well, it did.  The nitrate level 
declined and my Rotala wallichii stopped growing and turned blackish. 
Hemianthus micranthmoides also stopped growing.  P. stellata was still 
growing, but stems became quite spindly.  I added 1/4 tsp of KNO3 and the 
miserable looking leaves of R. wallichii started showing a bit of green the 
next day.  With another 70 % water change and a regular fertilizing, I am 
back to where I was.  My new plants has picked up their growing speed, but 
Heteranthera zostifolia look postassium deficient again.  My old plants are 
not growing and nitrate is up again.  I am looking at my plants and trying 
to figure out what they are telling me, but with a lot of new plants, things 
got rather murky to me.

Tomoko




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