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EI and high No3 Levels..


4 Jun 2008
Ten days into my EI Dosing Schedule and i decided to measure the levels of No3 in my tank, i know that test kits are not the reliable, but i gave it a go anyway only to find that the levels were pretty high in my tank.
my london tap water has plenty of No3 about 10-20
my tank is sitting at around about 80+.. (3 day before a 50% water change is due)
i did do a bit of moving tank stuff about today, which in turn kicked up a lot of substrate to create cloudy water ,,, still not cleared, but 70% clear...
is this normal after a gravel kick up

No2 levels & ammonia levels .. pretty perfect...

The fish seam fine, well my clown loches seem happy enough to swim up and down the front of the tank looking for a hand out of food...
can't really tell with the tetras..

or Do i not have enough plants to deal with the up take of No3?
i had just rescaped and removed a lot of moss,ferns and a few sword plants.
i went with a rescape of slower growing plant, mostly anubias, moss (alot less moss) crypts and a lot less ferns,.. i have a few fast growing lillys with leaves the size of your head....!!!! :lol:

Tank schedule
Info = 60 Gallons 1.92 watts/Gal 213-275 approx.liters

Sunday 50% water Change
Monday KNO3 ¾ tsp + 5ml Florish
Tue KH2PO4 3/16 tsp + 30ml of Trace solution (30ml of mix to 500ml tapwater solution..)
Wed KNO3 ¾ tsp + 5ml Flourish
Thur KH2PO4 3/16 tsp + 30ml Trace Solution
Friday KNO3 ¾ tsp + 5ml Florish
Sat KH2PO4 3/16 tsp + 30ml Trace Solution

should i reduce the Kno3 fertilizer...?


Expert/Global Moderator
11 Jul 2007
Chicago, USA
Well, there is one thing I don't understand: If you know that the test kit is rubbish then why would you even think about using it? So now the kit tells you the level is 80+ and you believe it, knowing it reading is rubbish? So you'll now base future actions on a known rubbish reading? :rolleyes:

If KNO3 is dosed per EI then in one week you've only added 20 ppm NO3. If your water supplies 20 ppm. Even if this was a bare tank and you removed 50% of 20 ppm water and replaced it with 20ppm, the net concentration would remain 20 ppm after that first water change.

During the second week you add another 20 ppm so by day 14 you'll have 40 ppm before the water change. If you remove half the 40 ppm water and replace it with 20 ppm water, the net would be 30 ppm wouldn't it?

Now this arithmetic assumes no plant uptake but also assumes no nitrate production from the tank itself due to nitrification, so these two factors more or less cancel each other unless you're stocked/feed heavily.

So an 80 ppm reading is not believable unless you have something unusual going on in the tank. Your fish are fine and are behaving normally so I don't see a problem.

If you are worried about it, and if you have mostly slow growing plants, then either reduce the dosing or don't dose KNO3 at all. If you see deficiency effects or BGA then resume the dosing.

It's also not clear why you are spending money on dosing Flourish when you are already adding Trace Solution. The two are the same. Also, mixing Trace powder with KH2PO4 is not a good idea unless you are adding some chelator to keep the iron away from the phosphate. You should have two mixtures, the first should be KNO3+KH2PO4 and the second should be Trace by itself.


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