Dwarfism tends to be classic CO2 deficiency.
Low NO3 can cause this as well, but CO2 is far more common.
I've taken plants grown in the CO2 rich tanks and placed them into the same type of tank but no CO2/water changes etc. They all gfet the classic dwarf appearance.
Be careful with not adding KNO3, the NO3 test kits are particularly poor at the extreme ends of their ranges => the low and high ends.
This is true for any and all test methods.
I think many can eyeball a tank and know if adding KNO3 is required.
However...... adding more KNO3(say 10ppm extra week etc) should not have a negative effect on a tank either way.
There should be now negative effect from 20ppm NO3 vs 30ppm NO3 in other words.
If your kit is off by 10ppm, then that gives some buffer and about a 3 day supply under higher growth conditions before trouble starts.
The real question is is adding a bit more harmful? What can be gained by adding a tad more? Is it hard and is it worth the trade off?
I certainly think it is and have never seen anything negative impacts due to adding 10-20ppm extra per week.
If folks do see negative impacts from this, then they where very limited NO3 or perhaps K(easy to figure which one by adding K2SO4 instead) and adding it increased the CO2 demand etc, then that, not excess NO3, led to the issues
you can easily have low PO4/Fe/NO3 etc if you are low on CO2 or light.
As you have more light, you nered more CO2, as you add more light/CO2, now you need more N, some can come from the tap or fish waste etc or add another 10ppm if not sure for the tank using KNO3.
If you limit one nutrient, then the uptake of the others will be reduced.
That can cause NH4 to linger and not be removed nearly as fast from the fish waste and turn into NO3 or induce algae spores.
There is nothing wrong running a tank with fish waste, or lean etc, but there is a trade off and kno0wing what negative effect of higher levels is reasonable question to ask your less, less is not always better.
Many want less NO3, but more light, or higher CO2 but less PO4.
That always leaves me scratchin my head.
Run everything(klight/CO2/nutrients) lean if that's the goal, or run everything richer.
Neither method will give you algae and both can produce a nice tank done correctly.
I generally suggest starting with a goal in mind, then stick with an overall approach, not piece mealing parts of one method and adding to another.
A middle ground approach would be using Excel in lower light tank or CO2 in lower light tank etc.
Some are finally revisiting the virtues of lowering lighting recently.
You might even try lowering the amount of light and that often will reduce the dwarfism. Then you know it's CO2.
Regards,
Tom Barr
