[brenmuk]

Hi

There was a litle discussion on another board (non english) about what the plants prefer to use as nutrition.

One view was that the plants prefered Ammonia over nitrite, but would use nitrate when the two former was exploited.

The other vie was that the plant prefer Ammonia, cannot use nitrite, but would use nitrate when there was no Ammonia. According to this view the nitrite might pe poisonous to the plants.

Now I hope to get more info on the subject, since there seems to be a lot of knowledge on this forum, I am trying here.
Are one of the former "statements" correct, or is it something inbetween?

I think this is kind of an academic question because on a practical basis if you add NH4/or NO2 as a one off fert then you risk toxicity to fish etc and NH4 spikes have been put forward by Tom Barr as triggers for algae growth.
If you add NH4/NO2 on a regular basis your biological filtration will adapt to the higher levels and produce more NO3 (or your plants will get it first) but why bother risking toxicity/algae?
If you want to add extra NH4 then just add extra fish - they produce it constantly .