Hi all,
I have a tank that has only anubias species and java ferns I use easy carbo and profito but my plants don't look good. ........As for dosing, I have been considering stopping. My logic is this; they are slow growing plants and I have quite a few fish in the tank, I'm thinking they would probably get all they need from the waste the fish produce? I don't need the plants to grow as quickly as possible, I just want them to look healthy. Is this a bad idea?
I'm fairly sure that your plants are lacking one or more nutrients, but also that stopping most dosing may be the answer. The missing nutrient is likely to be nitrogen N, most safely added as nitrate, NO3. I use the orchid, bromeliad, fern, succulent or alpine growing approach for slow growing plants like Java Fern and
Anubias ssp, it is aimed at growing plants with low potential growth rates in nutrient poor conditions.
Duckweed Index
I use a floating plant (any-one will do, but I usually use
Limnobium (Amazon Frogbit)), as a visual indicator of when I need to add nutrients. I've called this the "duckweed index", but index is much too specific a term and it is just an easy way of assessing the health of your plants. I used a floating plant to take CO2 out of the equation, and I prefer
Limnobium (or Duckweed,
Lemna minor, L. gibba, Spirodela polyrrhiza etc.) as they have naturally dark green leaves without hairs etc, and show a quick greening and growth response. You can also reduce nutrient levels to pretty low levels with
Limnobium, whilst the Duckweeds fail to persist in soft water at very low nutrient levels.
There are details and photos here: <
http://www.ukaps.org/forum/viewtopic.php?f=17&t=14400>. You don't need to know your conductivity, you can just use plant colour and growth as an indicator of when to feed.
You can also use the amount of floaters as a way of regulating the light reaching the plants in the tank, it is mostly trial and error, but you should be able to get a balance where the plants are happy, but algal growth is limited.
Profito and Easy Carbo
These plants are fine without CO2, or liquid carbon supplements, (these are glutaraldehyde based, but work in the same way as adding gaseous CO2). "Profito" is a source of potassium (K+) and micro-elements, but doesn't contain any nitrate (NO3-) or phosphate (PO4-).
Macronutrients
Along with carbon (C), the 3 macro-elements plants require most of are nitrogen (N), phosphorus (P) and potassium (K), with the plants requiring something in the order of x10 as much nitrogen and potassium as phosphorus.
All macro and micro-elements are required for plant growth, but as intimated in the name, plants require a lot less of the secondary and micro-elements (magnesium (Mg), calcium (Ca), iron (Fe), boron (B), chlorine (Cl), sulphur (S), manganese (Mn), zinc (Zn), copper (Cu), molybdenum (Mo), nickel (Ni), selenium (Se), and sodium (Na)).
Light (PAR or "photosynthetically active radiation") drives photosynthesis, and photosynthesis drives nutrient uptake (including CO2). The whole process is like an assembly line, with plant growth restricted by which ever resource is limiting (PAR, CO2 or macro/micro-nutrient availability). Adding more of a non-limiting element doesn't increase plant growth, but it may prove harmful as some micro-nutrients are toxic at higher levels, the extra-energy from light may damage photo-systems, or high levels of one nutrient may block uptake of another nutrient.
Because we have plants that aren't rooted in a substrate we can ignore substrate nutrients and just concentrate on the water column. Java Fern and
Anubias species will grow more quickly with added CO2, as long as all the other nutrients and light are non-limiting, but this is true of all plants. This won't be a particularly quick response, or produce a lot more growth, because these are plants with relatively low potential growth rates. The same applies to nitrogen etc. more nitrogen will produce more growth initially, but nitrogen above the level where it is the limiting nutrient, won't produce any more growth.
cheers Darrel