# overdosing ferts?



## stan1973 (19 Dec 2011)

Hi

Can someone please tell me what the target nitrate is as I have worked out what I am adding after following this calculator:
http://blog.fluidsensoronline.com/calcu ... ive-index/

My tank is 5'x2'x18", I measure the water depth at 20" excluding substrate so comes to 330 liters water and used it in  the online calculator.

I make up 31 g of KNO3 in 1000 g of solution and add 165g on days 1,3 5 so added 15.3 g of KNO3 .
KNO3 is 61% Nitrate.

15.3 x 0.61 x 1000/330 = 28 ppm Nitrate

But that's for the whole 330 litres, I'm only actually dosing the 50% water that I change so its actually 2 x 28ppm = 56ppm nitrate.

I vaguely remember reading years ago that the target was roughly 10-25 ppm and above that it stunts the plants, can someone please double check my calculation and tell me what the target nitrate is?
is it true that too much nitrate stunts plants & fish?
It's just that it looks too much to me, I did a 50% water change about a week ago and I think my plant growth has improved?


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## spyder (20 Dec 2011)

stan1973 said:
			
		

> I vaguely remember reading years ago that the target was roughly 10-25 ppm and above that it stunts the plants, can someone please double check my calculation and tell me what the target nitrate is?
> is it true that too much nitrate stunts plants & fish?



Some have double maybe even triple dosed with EI with no ill effects. This is sometime done with larger tanks with lower flow. It's the first I've heard of nitrates stunting plants but that doesn't make it true or false.


Sorry I can't help with your calculations, I'm a tsp man myself.


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## AverageWhiteBloke (20 Dec 2011)

Not sure if I'm reading it right do you mean you put 165ml of the mix into the tank 3 days a week? looking at james http://www.theplantedtank.co.uk/calculator.htm each dose would put in 9.5ppm per dose so the three doses adds about 29ppm per week to the tank.

In james 33gram is mixed with 250ml water and 35ml dosed 3x, as you are using 1000ml the same dose is added give or take but your adding 165ml so as far as EI dosing nitrate goes your somewhere in the ball park I guess off rough maths. 
It's not what you call exact science anyway, EI is a way of making sure you have more than enough ferts rather than having to fine tune stuff.

People generally dose the full volume of the tank as oppose to the amount of water changed to be sure as each tank is individual and no one really knows how much of the ferts the plants have used. EI is a belt and braces approach to dosing and tries to provide more than the plants could use regardless of the lighting so if you want to reduce the amount put in you can gradually until you get a negative reaction from the plants.

Other than that Nitrate over dosing is not seen as a big problem, if it stunted plants some of the top people in here would have been all over it by now and with fish it's an on going discussion but not seen as a problem. At high levels fish seem to be healthy and will still spawn.

Edit I'm also a teaspoon man   In effect though your title "overdosing ferts?" is about right. EI is a simple way of ensuring that more ferts than your plants could physically consume are added with the brightest of light so you are so to speak over dosing just not too the point of being uneconomical or detrimental too the living things.


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