Can the red in some plants be used as a NO3 Indicator?

ceg4048

Lifetime Charter Member
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Mar 21, 2005
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Hello,
Ever since implementing the EI procedures I've noted that some plants which normally have a red element to their color pattern such as the "Sunset Hygro" have suddenly lost this red component. A NO3 test typically confirms (as accuracy permits) higher NO3 levels than when I was not dosing per this procedure. If I refrain from dosing the KNO3 to allow the NO3 concentration to fall and if I maintain all other dosing per EI such as micros and KH2PO4, by the end of the week, I notice the red/pink returning to some of these plants.

Naturally the all-red plants such as Alternanthera are not affected, only those which have a variagated red component. E. x Barthii, which at much lower NO3 levels sprouts new leaves having a deep red color changes at higher indicated NO3 levels such that the new leaves emerge a pale beige and the mature leaves loose all their red. Again, as the NO3 level drops the new leaves appear to regain some of the red.

Is this color change a coincidence with some other factor or is there a relationship between the red/pink colors and NO3 levels. If so can this "behavior" be used as one of the reliable visual indicators of a falling or a "threshold" NO3 level?

Cheers,
 

GreenStuff

Prolific Poster
Feb 11, 2005
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Re: Can the red in some plants be used as a NO3 Indicator?

That's a good question. I have noticed the same thing in my tank since implementing EI, and since I can't trust my NO3 tests, it would be nice to judge it by something, .......other than my fish dieing. :eek: (Kidding.)
 

Tom Barr

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Jan 23, 2005
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Re: Can the red in some plants be used as a NO3 Indicator?

No, you are correct.
We fanatisized about making plants redder years ago, then we figured it out.

Low but stable N will allow plants to maintain a red color, the problem is, bottoming out the NO3 wills tunt the plants at higher light.

Be careful not to do that.

Regards,
Tom Barr
 

Urkevitz

Junior Poster
Mar 29, 2005
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Re: Can the red in some plants be used as a NO3 Indicator?

Would cutting No3 additions in half be a good way to bring out reds?