[JamesC]

One question that has never been explained to me is why do some manufacturer's use ammonium or urea based compounds in their products as a source of Nitrogen. On all forums I visit it is drummed into you how adding ammonium and urea to your planted tank will create algae mayhem and that potassium nitrate is the way to go. Do the manufacturers know something? I even tried replacing potassium nitrate with urea keeping the N amount the same for several weeks but didn't notice any difference in plant growth nor did I suffer any algae outbreaks.

James

 

[JamesC]

I have decided to give dosing urea a go and see if there are any benefits. All plants currently grow great except for two. These are Alternanthera Reineckii 'lilacina' and Ludwigia Glandulosa which seem to grow with small and deformed leaves. I could of course always ditch these two plants but I like to persevere with them. I have tried different dosing stratergies from heavy EI through to a fairly lean dosing system that I currently use. Actually I found the heavier I dosed the worse the problem became with these two plants.

Been dosing urea for a few days and so far no problems. I'm adding 0.5ppm urea daily and have reduced the potassium nitrate so that the total nitrogen has remained the same. Potassium sulphate has been increased to compensate for the reduced potassium from the KNO3.

What I'm looking for is obviously an improvement in plant growth but also how nitrate levels change. If they drop then this would suggest that the plants are using the urea, but if they remain the same then this would suggest that the filter is getting to the urea first and converting it to nitrate. Because urea has a very high N content I'm now dosing about a third of the potassium nitrate as I was before, which is quite a difference.

I'll update this thread on any progress.
James

 

[JamesC]

It's been two weeks now since I started dosing urea and I have noticed a dramatic change in my Alternathera Reinekii and Ludwigia Glandulosa. Both are now producing much larger and non-crinkled leaves compared to before, which I must admit has surprised me. All other plants are growing exactly the same as before except maybe the Rotala Macrandra which seems to look fuller and healthier.

This better growth could be due to the added urea but it could also could be due to the lower levels of nitrate that I've been dosing. Next step is to increase nitrate levels again and see how the plants react.

There have been no noticeable effects to fish or shrimp and also no algae problems.

James

 

[JamesC]

JamesC, I would like to hear/see more about the change in the leaf appearance you've noticed by dosing ammonia.

Before dosing urea

After dosing urea

James

 

[JamesC]

Funny you should mention it as I've just stopped dosing the urea about 3 weeks ago and gone back to straight potassium nitrate. So far to be honest I haven't noticed any real change so am now coming round to the idea that perhaps it wasn't the dosing of urea that had the effect as during the dosing of the urea I also suffered stunting at times.

I still have the Ludwigia Glandulosa which sometimes grows fine and other times doesn't. I'm still at a loss as why it happens. And before others jump in and say CO2 I'm going to say that I've had CO2 and flow levels really high and have also given the Ludwigia Glandulosa it's own personal supply of CO2 mist. I'm now strating to believe that it is to do with growth rates and that trying to make it grow too fast causes the deformations. I've dropped the T5's in favour of the old T8's and will note to see if this makes any difference.

One thing I have noticed is that the blyxa japonica does a lot better with higher nitrate levels.

James