Re: Astonishing
awrieger said:
If you don't mind, I'm going to refer to it as the Barr Ratio if you haven't already christened it. 7:1.
Technically then, any 7:1 multiple of NO3

O4 will work. So even PO4 at 5ppm should not induce algae if NO3 is 35ppm.
Perhaps the tests they did showing high PO4 levels inducing algae were done without referencing it to the NO3 levels, so in a sense they were correct, but they missed the crucial factor - eg high PO4 does induce algae IF it's not balanced by NO3, so in that sense they were way off-beam.
No, they simply never did any ratio work at all, nor added any PO4, they assumed any excess PO4 caused algae but also conceded that plants still needed PO4.
A rather conflicting premise.......
So they tried to add PO4 etc to the substrate.
A similar thing and approach occured with NO3, until fairly recently when I started nagging about NO3..........
Just like when I nagged about PO4......
N

ratios may provide some relief if you have kept low PO4 levels or also, low NO3 levels.
Some plants like more NO3 than 5ppm say.........re read the nitrogen article here..........
EI will certainly target the N

ratio you desire, you can test with calibrated kits etc for confirmation.
There is still no need for test kits.
The ratio itself is not that critical, having enough NO3 and PO4 is much more the issue. Generally, a lot PO4 takes out glass algae.
Which is 180 degrees opposite of what many predicted.
But until you start focusing on the upper ranges, you will not find these things out. Folks in the past have always limited thing.
EI assumed a max, not a limiting approach.
If you cannot hit 2-4ppm of PO4 and 14-28ppm of NO3 without a test kit, let me know.
That's a big range and plants/tank will not use much more than 2-4ppm of NO3 even at very high light, and .2-.6 ppm PO4 per day.
So dosing once every 2-3 days should maintain that fairly well.
If you seek more accuracy, you can make solutions of KNO3, KH2PO4 and that will provide greater accuracy for your target range without test kits also.
We already do that with Trace elements.
The dosing calculators can tell you precisely what you need to add to say 500mls of water to make a soultion based dosing method.
Yes, you can maintain a range of 7:1 and go higher than the levels you have set for yourself.
That's the thing with assuming max levels for a range, it offers much greater flexibility than a specific target.
Then you do not need the test kits.
I've tested for a long time, there are reasons why I do not suggest folks as a rule need to test for N

.
You can test if you want, but you do not need to tell folks that they need to do it.
I'm not saying they are worthless, I am saying they are not needed to hit the targets for good growth/low algae.
If you asked someone prior, and told me the glass algae issue, I would have told you to increase the PO4 dosing(and likely the CO2 if it still persisted), and not a 7:1 ratio.
Regards,
Tom Barr