should I stop dosing KNO3 - The Planted Tank Forum
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post #1 of 2 (permalink) Old 06-20-2009, 09:45 PM Thread Starter
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should I stop dosing KNO3

hello I have been dosing My 72 bow E.I. Style for about a year but recently notice that my nitrates stay in the 30-40 ppm range regardless of when i dose. Even when I lower my kno3 doses it still ranges around there. On this tank I have a wet dry filter and these are known to be nitrate factory's. Does this mean I can stop dosing kno3 or can I just dose 1/3 of the recommended amount?
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post #2 of 2 (permalink) Old 06-20-2009, 10:12 PM
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I think a better question is have you calibrated the test kit that you plan on basing all the dosing routine on in the first place?

Here's how to make a reference solution set and check to see if the test kit is giving you the correct readings or not.

They often do not use a calibration solution for NO3 and PO4 and folks adjust their dosing based on the inaccurate/imprecise test kit readings. the color charts are often lousy to boot.

So unless they are calibrated and used correctly(calibration is done in research for this very reason), test kits are really estimative at best, and outright misleading in many cases.

Goading people into using test kits is hard enough, getting them to make and use calibration solutions is even harder. Then getting them to use them consistently over time is another issue.

I know of no one that's kept planted tanks and test consistently for the last 10 years(say weekly etc for NO3 and PO4 and does calibration). They might be out there, but I've not met them or heard of them.

I prefer and use higher grade test kits and methods.
Always have. Good stuff pays for itself, and when you plan on relying on it for assumed critical issues(whether they are or not), even more so.

"Wet/drys are NO3 factories" because there's no plants, with plants, the NH4 is removed directly and little is converted into NO3 via bacteria in the filter.
So with plants involved, this changes the wet/dry filter's NO3.
Plants also take up NO3 at high rates.

If you have about 220W or so of PC, or T5 lighting, you are fine, if you have less, say 100-140W, likely can get away with say 1/2 EI, if you use ADA AS or MS, 1/3 is fine with this same light level etc..............high fish loading/feeding etc will also reduce the demand.

Yet another way is to slowly and progressively adjust the KNO3 down, say 10% less for 2 weeks at a time, and watch plants and the tank.
Once you see BGA or a negative growth response, then bump back up to the next highest level.

So experience, light/holistic approach, slowly adjusting, testing all can and do work well, when done right.

Not everyone has experience, not everyone is patient enough, not everyone likes and will use test kits etc. Some just learn the hard way

I suggest watching CO2 the most of everything (it's far more lethal to live stock and will cause algae issues than any NO3 possible with any dosing routine) and then tweaking the nutrients down, not just KNO3 alone.

Tom Barr

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