Now throw away the word * consistency* from your logic line, and try to stack in EI system *user friendly* concept. We are humans and inconsistent, have no time etc …
Haha, more than you know!
I learned about people before I learned about plants.........
I suggest folks to use LESS light, you will see me do this many times.
That saves them from most of the issues, and many report much better results with using less light, generally in the 2-2.5 w/gal range or less.
This includes several clients as well.
They all started out with lots of light and now use a fraction of it.
This is a very common theme going back 15 years.
Then, if the neglect the tank, they have much less trouble and lot more time before it really goes down hill.
If the person knows they tend to neglect tanks, then a non CO2 approach is very suitable.
So there are options that meet everyone's goals here.
Low light/non CO2
This gives people a number of choices all of which are easy to mange and increase the rates of growth to match their goals.
They all successfully grow plants, but at different rates of growth.
When we afraid of algae and dose less and less (beginners case).
When we missed several doses (no time, no new ferts, when we have algae because of NH4 etc).
When we dose less ferts when have problems with stunted plants and do no know why exactly (low Mg, Ca, Fe, K etc)
When we have algae because of low CO2 (bad reactor, dirty reactor, low bubble rates, exhausted east solution etc)
Every time we have algae, regardless of the reasons.
We always dose less nutrients as dosing more in such situations will feed algae.
We start to do massive water changes.
This way we reduce nutrients base for algae, reduce NH4+ and build up of organics.
Unfortunately this substantially lowers CO2 concentration too and starve plants on P and N.
Here you have a period when plants are… limited on nutrients.
(Note: sure this does not the case when we have rich substrate)
What will be the case if algae appeared because of low CO2?
Again we do massive water changes, and do less water column dosing.
Plants become limited. Algae are not.
Does it make any sense to allow for plants to have more N left in internal buffer and a little bit more N “leftovers” in water column? Yes.
Does it make sense to have less P in water column to have less algae biomass in this period? Yes.
If you have lack of CO2 plants will quickly run out of N and will not use lower CO2 levels = will not grow. Why?
When you constantly dose 1:5 plants have low N buffer (having lots of CO2 and enough light they use those non limiting P levels for growth really exhausting N). Plus you have much more P build up in case of problems and more P left for algae.
When you dose more N than P (as says Redfield ratio) pants will have large internal N-buffer and easily overcome those two-three weeks of inconsistent dosing of ferts and/or low CO2 due to low bubble rates or during massive water changes while eradicating algae. When they ARE limited. Isn’t that? (fix me about how long they can live on internal N and P buffer, plz)
So, is it wiser to allow plants to have more internal buffer on N and left N in water column after massive WC’s? Yes.
While you consistent with dosing there is no sense in P:N ratio.
I am talking NOT about situation when everything is OK and P:N ratio really has no matter, but about cases when algae becomes a problem and we DO limiting our plants being Not consistent.
Is it good habit to say dose more N than P? I do not think so. I do not have evidence to show that it is in planted systems.
This will NOT harm, NEVER, but will help to overcome problems “when plants are limited” while you have not consistent dosing regimen, low CO2 etc.
When we have unlimited nutrients supply in substrate do this 1:10-15 have any sense?
YES, because with massive water changes during algae outbreaks there is no sense to keep in water lots of P – it will feed algae.
Naman, you are hung up on the issue that algae are P limited in our tanks, they simply are not and this has never been shown to be the case, ever,.
I've done enough aquarium algae experiments in my day to know this is not correct.
This is the flaw in all of this.
This is also what was claimed about 12-13 years ago by Paul Sears, he was wrong and knew it after we showed more and more evidence.
Algae are never nutrient limited in a plants fish aquarium.
They never have been.
They grow and appear for other reasons, not because they are limited.
By limiting the plants further with PO4 chemical removers, you only stress the plants further, the algae will slow some, but they are not going to be beaten, and it will be at the expense of plant growth.
When nutrients get low, plants will suffer more in terms of growth rate than algae ever will.
This is common research knowledge in marine and freshwater limnology, aquatic science.
The smaller the organism, the less it's nutrient demand.
This is true across the biological world.
This does not just apply to aquariums.
The less P – the less algae biomass during disbalance.
And, importantly....... less plant growth as well.
You hurt the growth rate of the plants more than the algae, thus provide more competitive advantage to the algae, not the plants.
Algae are much better adapted to grow a lower levels than plants.
The same is true for marine macro algae/marine plants and micro algae.
Than, we can use as more PO4:NO3 ratio until there is no harm for plants, i.e. keep close to Redfield ratio.
The ratio has nothing to do with it though.
It never did.
This is completely about limiting ranges, you cannot bounce back and forth, or use a revolving door with ratios and limitations.
You have a limited system for plants, poor cO2, poor dosing.
Then you want to move into a PO4 limited system for plants(1st), then say that the algae are PO4 limited.
You need to sit down and think about this more.
Pick one situation at a time.
The plants are limited with CO2, with dosing(many possible variables here) and now PO4 limitation.
I'm not clear why you think this "method" is the least bit useful to anyone?
It does not focus on the needs of the plants.
Any method that ignores that to prevent algae is a poor method by any horticultural standard.
It clearly gives the advanatage to the algae and pest, not to the plants.
If we have most nutrients in substrate we can dose for very low P levels as it is supplemental nutrition ONLY (for hungry stem plants) and to do not exhaust substrate too soon (it is hard to make pool P in substrate because CEC have low ability to fix P, maybe Rock phosphate will help). Note: Assumption - To make this trick to work plants have to be already adopted for a little bit lower CO2 levels (say 15ppm instead of 25-30ppm), so we have to get them be “trained” limiting their growth with less light (daily PPF).
Something tells me measuring CO2 is the main problem here.
I have trouble and adding peat and other acids or non carbonate buffers make the rror ranges very high here, at least 10ppm either way.
When I recently used a special CO2 meter using non pH/KH measures, I was off by 7 ppm even with the best pH and KH measurement methods.
So I know other folks, hobbyists are way off.
Eye balling CO2 seems to be about the best method with a really good meter.
And if that is not accounted for, then the results really are not what they are claimed.
Also, you make a very bad assumption here, PO4 is not locked up in the sediment.
Plants leach and export PO4 right out of the sediment.
Please review Barko et al.
The nutrients in sediments are actively exported out of the sediment to rather high levels that make algae growth far far from anything remotely limiting.
P32 studies have shown this numerous times.
We have done this at the lab where I work.
Lower P levels will not harm in any way, it is proved.
It depends on the questions asked.
If the critical P level is too low, then plant growth is definitely affected.
Then you have a situation where the plant growth is limited and the algae not.
The better studies I've read showed this clearly in the Everglades. It is the most researched aquatic plant periphyton algae region in the world.
The South Florida Water Management District(SFWMD), found that aquatic plants where effective for PO4 removal to about 50 to 20ppb, that's it.
They did not stop even below 20ppb even
You really cannot do detection monitoring below 10ppb and have a good error range in your measurements.
That's at the best possible research methods and labs money can buy basically.
I've talked to the lead principle researchers there.
They gave a nice talk at the UF.
I grilled them but they knew far more than I about ranges and hard data.
They had every answer for any thing I threw at them.
That's research I know I can trust.
Backwards – it is much better to have more N in a system than P at any given time.
No, it applies when you reach that critical P or N level, the ratio does not matter until then.
Especially when you use system based exclusively on water column dosing (EI). Ole’s data and PJAN experience shows this for some degree.
I think you need to talk to Ole in person.
I know him and we have talked about such things and quickly agreed.
And we(Troels and Claus as well) also agreed that aquarist misunderstand and misapply concepts, principles and interptations, the researchers all get and understand it.
We get the relationships, aquarist that do not, make a big stink over it.