Aquatic Plant Central - View Single Post - How to balance NPK, Ca, Mg and micros

BryceM · 07-01-2007, 11:41 AM

Kekon this is very good information. I think it's pretty silly of us to state that nitrogen needs to be kept between x and y, etc. As far as I'm concerned there is a growing body of evidence that nitrogen needs are much lower in systems with soft water.

As far as potassium is concerned, this is something that I've suspected too. Amano for one is very keen on potassium dosing but less enthusiastic about N and P except in cases of high-light, high-CO2, rapid-growth plant situations. I'm becoming gradually convinced that the typical EI methods of supplying K as a byproduct of dosing KNO3 and KH2PO4 probably results in too much NO3 and too little K in most situations, especially with softer water. I haven't had too many issues with tip stunting with my current fert regime except for with Pogostemon stellatus. I'm gradually cutting back on my NO3 and PO4 dosing which has helped with bothersome green algae on the glass. I've been thinking I'll need to start K2SO4 dosing at some point to avoid too little K. This will be a fun experiment.

Your writeup reminds me that I should look at this more carefully. Thanks for all of the info.

Regarding R. wallachi, some have found that Mg excess (over 10ppm) results in tip stunting, but this is nothing more than an anecdotal observation. Clearly the "rules" of dosing are highly dependent on the setup, lighting, CO2, substrate, and other parameters that are defined for any given question. It would be silly to assume similar results between a tank with an inert substrate, medium light, and hard water and a tank with ADA's Amazonia, high light, and very soft water.

My current "pet" theory is that very, very low N and P levels (by our current standars) are ideal, provided that they can be kept consistently present in stable quantities (just like nature - go figure!). Allowing a severe N shortage to develop (especially suddenly) is a great receipe for disaster. Nitrogen excess has always resulted in green crud on the glass in my tanks. Let's all remember that the addition of N and P to an aquarium was thought to be a disasterous idea even as recently as 10 years ago.

07-01-2007, 11:41 AM	#4 (permalink)
BryceM Administrator Join Date: Nov 2005 Location: South Central Idaho, USA Posts: 4,262 iTrader Ratings: 42 iTrader Positive Rating: 100% Plant Points: 178534	Re: How to balance NPK, Ca, Mg and micros - new experiments Kekon this is very good information. I think it's pretty silly of us to state that nitrogen needs to be kept between x and y, etc. As far as I'm concerned there is a growing body of evidence that nitrogen needs are much lower in systems with soft water. As far as potassium is concerned, this is something that I've suspected too. Amano for one is very keen on potassium dosing but less enthusiastic about N and P except in cases of high-light, high-CO2, rapid-growth plant situations. I'm becoming gradually convinced that the typical EI methods of supplying K as a byproduct of dosing KNO3 and KH2PO4 probably results in too much NO3 and too little K in most situations, especially with softer water. I haven't had too many issues with tip stunting with my current fert regime except for with Pogostemon stellatus. I'm gradually cutting back on my NO3 and PO4 dosing which has helped with bothersome green algae on the glass. I've been thinking I'll need to start K2SO4 dosing at some point to avoid too little K. This will be a fun experiment. Your writeup reminds me that I should look at this more carefully. Thanks for all of the info. Regarding R. wallachi, some have found that Mg excess (over 10ppm) results in tip stunting, but this is nothing more than an anecdotal observation. Clearly the "rules" of dosing are highly dependent on the setup, lighting, CO2, substrate, and other parameters that are defined for any given question. It would be silly to assume similar results between a tank with an inert substrate, medium light, and hard water and a tank with ADA's Amazonia, high light, and very soft water. My current "pet" theory is that very, very low N and P levels (by our current standars) are ideal, provided that they can be kept consistently present in stable quantities (just like nature - go figure!). Allowing a severe N shortage to develop (especially suddenly) is a great receipe for disaster. Nitrogen excess has always resulted in green crud on the glass in my tanks. Let's all remember that the addition of N and P to an aquarium was thought to be a disasterous idea even as recently as 10 years ago.