As mentioned,
Commercial brands are nice.
I use Tropica for my trace mix, but lately I developed my own which is better and 10X cheaper.
Cost is one trade off that folks may not care about, so they can use Tropica, ADA or SeaChem etc.
If the rates of growth are really a concern, then use less light.
This is plain old fashion common sense and does try to fit a square peg into the round hole approach used by the limiting folks who also have the bad habits of claiming certain nutrients limit algae, when in fact, they limit plant growth and the reduced uptake from slowed growth is what is the real effect, not limitation of the algae.
So if you limit PO4 a lot, then the demand for CO2 is going to be controlled by low PO4, not anything else.
But if you add PO4, this no longer decreases the demand for CO2.
So if you had problems adding good stable CO2, and you do well with low PO4, then you get algae when you add high PO4, it's because you are terrible at controlling the other factors, not because excess PO4 causes algae :idea:
Now if you cannot measure and control CO2 effectively, and it's 45% of the plant's biomass, and errors/ variation in the delivery of CO2 causes algae and we can test it, I have a hard time listening to these folks argue and bicker with me about their own lack logic.
I can test PO4 better than that.
I can add 2-3 ppm and see that I have no issues with algae.
So it's not the PO4, it was the CO2, or the light, or current, or some other factor they did not consider.
That I can prove.
I cannot say what errors they might have done, there are many!
But if you lack control, then it's an issue, and you might not trust other folks.
So you have folks claiming stuff the rest of us know that is not correct.
As far as EI being the only method, no, you can modify it greatly to achieve whatever goals you might have.
Less growth? Try less light, that's the best way to reduce rates of growth.
Trim more etc.
But people get/are lazy.
So they look for short cuts.
Still, less light = less CO2 demand, less nutrient demand, more % from fish waste contributing, less electrical and initial set up cost, less heat, less algae growth!
Does low PO4 do all that?
No it does not.
So why, given the trade offs aquarist want and desire, would you bother using that method?
Now say you want even less hassle than dealing with CO2.
You can use Excel and dose about 1/4 the rates of full EI, use 1.5 w/gal of T5 lighting.
Water changes once every 2-4 weeks.
Say that's too much work for you.........now you can do the full non CO2 method and never do water changes for months/years even.
Each method reduces the growth rates via light and then by carbon source.
These are the two basic drivers that account for the most of the energy and biomass produced, not PO4.
While EI adds all the nutrients, so do other methods one way or another, ADA adds very rich sediment based nutrients.
You can add ADA AS + EI and add say 50-60% full eI.
There's no law that says EI must be used at the full rate or without test kits or that you must do 50% weekly.
It gives you a starting place to try and go from there.
Some do 30% 2x week water changes.
Some do 70% weekly.
Some dose 1/2 EI's suggestions.
You should tweak the method to suit.
I make this clear.
But folks see/read one thing and then it's 100% rigid thereafter
Do not be that way.
Also, all methods all add the same building block nutrients for the plants, the NO3 from ADA, Tropica, or my sack of KNO3 are all the same.
You can add these at some rate to make sure the plants to do not run out, or run out for too long for a given CO2/light intensity/plant growth rate.
All methods are essentially the same in this respect.
PMDD, which is 90% of EI, is just that, you can dose EI daily as well and divide the total week amounts by 7.
PMDD suggested not adding PO4 because they assumed it caused algae.
I showed and argued it did not.
So I added that to modify PMDD and then used water changes to suggest there's no need for good testing/test kits.
Something folks seemed to hate and never would do correctly anyway.
Otherwise it's not that much different.
Some folks and companies like to claim they developed plant science entirely and that they never borrowed anything from any other method. Those folks are full of steer manure.
You give credit where it is due.
No one method will meet all goals.
EI does not attempt to do that.
It works well if you scale the dosing to the appropriate light level, CO2 and water change routine.
Like most any other method, plants all grow for the same reasons, just at different rates based on the supply.
Regards,
Tom Barr