I was wonderig if anyone could help me in my current situation. My 33 gallon tank got an algae bloom recently, and all my amazon swords(pale green, leaves brittle ), and anubis(turning yellow) are slowly dying off. The vals are still growing. I am unsure whether this is an excess of nutrients or a deficiency. A book says if there is an excess fast growing plants may not be affected since they can dilute the nutrient through fast production of new leaves, but slow growing plants have to increase their buildup of nutrient. But my amazon swords seem to also fit the description of iron deficiency. Any advice would be appreciated
The sword is a fast growing weed. The vals can use KH as a carbon source much better than the swords, but they can use KH as well, they prefer CO2(both/all plants do over KH).
This book is incorrect. The issue has nothing to do with dilution. Plants, all of them, are very good at controlling the nutrients and ions coming in. They have to. It is not a passive process where nutrients freely diffuse in/out based on concentration alone. Same is true for us, we are able to control the salt content in our blood.
We can swim the ocean and not turn into a pickle.
Plants are very good at "gate keeping" and are selective.
At higher concentrations, we can get to where they cause toxicity since the pressure is so strong, it can overwhelm the system, but this is far beyond anything we see in aquariums, your fish would be dead long before this occurs. Commercial growers use things like Hoagland's solution for aquatic plant horticulture. 235ppm for N, 210ppm for K+, 50+ppm for PO4 etc. About 10X more than anything we need or dose in aquariums without any ill effects.
It becomes more like salt stress than anything else at that point.
As far as reserves in the plant, this also is incorrect.
Fast growing plants are better able to use CO2 or KH, thus grow better under limiting or harsher conditions than other species, many species cannot use KH as a carbon source, so most of the really weedy submersed aquatic species also can use other sources of Carbon. When they have more carbon, they also will remove more nutrients, but those are indirect secondary effects. So the weaker CO2 only plants appear to do poorly, but it has nothing to do with the nutrients, so other factor is/maybe limiting.
Slow growing plants should already have plenty of nutrients in their vacuoles where most of the storage is. they can grow at a fair clip with good CO2 and moderate light.
At higher light, the weeds will grow faster. Weeds tend to be able to out compete the slower CO2 only dependent species.
So simply adding enough CO2, use moderate to low light, add sediment source as a back up for ferts, and change the water/dose routine resolves any of these speculations/issues.
What book claims this stuff?
Regards,
Tom Barr
