- Jan 23, 2005
Hi, this is a thread about N, P and C that's been moved here.
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 …
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.
The less P – the less algae biomass during disbalance.
Than, we can use as more PO4:NO3 ratio until there is no harm for plants, i.e. keep close to Redfield ratio.
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).
Lower P levels will not harm in any way, it is proved.
Backwards – it is much better to have more N in a system than P at any given time.
Especially when you use system based exclusively on water column dosing (EI). Ole’s data and PJAN experience shows this for some degree.
So we can safely dose less P (PO4:NO3 1:10-15) and have advantages “when algae problems arise”. When everything is OK it has no sense, but to improve system/method we have to improve it in situations when we have problems, right?
This is what drives folks to ADA’s system.
Less problems in case of low CO2 or not consistent dosing.
The aim is not to say water column dosing system (EI or else name) is wrong.
This is still the best starting point (or as you say a “concept”), not to mention your explanations on balance of a planted tank as a hole (priceless .
All you can fine tune in EI is to use 1:10-15 instead of 1:5, and you admitted it.
(ADA’s system is very different)
This way would be easier to overcome problems which happens when CO2 supply AND/OR nutrient levels lowered down for some time (during massive WC etc)
and to be satisfied with total absence of algae with say 10-15ppm instead of 25-30ppm of CO2. A little bit more stability.
Dosing less ferts will not make EI more stable or user friendly. Less light and bigger PO4:NO3 ratio is the right ways.
You are saying on how to stay “good” when everything is OK and you consistent, and everything you told is RIGHT.
I am talking how to stay “good” being not consistent.
WHEN you suddenly have limited levels of nutrients or CO2 (very bad and quite often), [P] MUST BE THE *F I R S T* LIMITED NUTRIENT - NOT [N] "in case of problems", not when everything is perfect.
I hypothesize (with mentioned scientific data) that it is wiser to give for plants more N pool than P to have less problems when algae already in your tank or CO2 drops.
Just to make plants less influenced by occasionally lowered CO2 levels and to do not limit plants ability to assimilate lower CO2 concentrations. This can give more stability.
when there is 3ppm LEFT in water, or when 0.05ppm?
I said that when you under dosed Macro or during massive water changes combating algae attack it is good to have some N LEFT when P is almost zero as N needed for Rubisco to assimilate CO2 better, at the same time plants keep much more P buffer so will not slow growth so much as if we have lack of N added to this.
This is a limited situation for plants, so some more N left would be beneficial for plants.
It is known that limiting N has much more detrimental effect on plants than P, so in case of troubles it is better to have some more N left than P. To help plants with lowered CO2 levels, NOT to limit algae.
Tom Barr;23784 said:I think part of the confusion on my part is trying to keep clear the various things you are suggesting.
=> You say that under a bad algae issue/condition, not to dose PO4 as much, because it causes more CO2 uptake/demand in plants, not because it limits algae.
I think that this is what you are saying.
naman;27385 said:Not at all.
Keeping as less as possible PO4 in water column (a lot of nutrients in sediments instead of this to NEVER limit plants!) in case of imbalance (when it already happened, regardless of the reason) makes algae bloom much slower and much less severe.
Pretty clear concept.
You have more time to fix things, need less effort, no CO2 concentration swings due to very big water changes which enhances growth of algae - not plants during this period.
This is the same as reach substrate makes possible to do not dose in water column regularly.
You can miss week or more without any detrimental effect.
Now imagine algae bloom already began in your tank.
Think of two cases - PO4 0.1ppm before algae bloom, and PO4=1.0ppm.
When it is 0.1ppm you will have much less algae per day, isn't !?