I have been maintaining CO2 between 27 and 30 ppm,
So you are sure that the CO2 is within this 3 ppm range all the time during the time you have kept this tank using this fert routine?
and you have DIY CO2, well, if I had a nickel for everytime I found the root issue was DIY CO2 with folks that made claims about nutrients........I'd be very rich.
Do you think CO2 production is slower or faster at cool or warmer temps?
What happens at night and during the day?
Do you think CO2 production and rates are stable over the times you change the brew?
I'm not saying DIY cannot be done without getting algae, I am saying the errors made and folks believing they can measure CO2 accurate are far more than mere suspect.
Let me put it another way:
How come I can set up and do a new tank, and maintain such tanks for years without having any algae issues? I use EI.
If EI was the cause, I would have to see algae.
Do you agree?
It's simple logic.
However, if you do not know and have not controlled for most things, many new folks do not, then you might be led to make poor assumptions.
You might assumer that it's low K, or high PO4.
Many do and have made such errors in their logic.
But clearly I'm not lying to you nor will others, so if you accept that EI or some excess ferts causes algae, then where are the algae ridden tanks?
Here's a tank that's been running for the last 3 years using full EI:
Where is the algae?
It cannot possibly be the nutrients.
What is different about your tank vs these tanks?
It's not the nutrients.
I can be sure/certain about the nutrients, CO2?
Even with high grade CO2 equipment and 2000$ meter, I only have accuracies to about 1-2ppm of CO2.
I'd figure at best, most have 5-10ppm accuracy, and some are simply wayyyy off. The other issue with CO2, how the ppms change throughout a day cycle.
These can vary widely.
CO2 is not static, one measurement at one time of day often does not tell you much, except at that moment.
But plants grow all day long.
That said, I am using DIY CO2 , which is not always (never) really consistent, and I am using the KH pH method for CO2 testing, and I realize this is not very reliable using my tank water.
And there's the smoking gun.
So, like you said, CO2 is likely the culprit for my past issues, and NOT EI. I was not meaning to criticize EI, just for me with my DIY CO2 I think a custom regimen is better.
Let me ask you something, do you think that the algae are limited with your dosing routine and testing?
Do you really think that say 2ppm of NO3 will limit any species of algae vs say 20ppm?
Now what about a much larger plant?
Why might this routine work whereas you failed with EI?
EI ruled out any nutrient limitation, except for CO2.
And CO2 is your Achilles Heel.
Using another limitation, say NO3, will slow down CO2 demand.
Then you think it's testing and custom routines and lean ferts that resolve algae, not CO2 issues.
But you'd be wrong.
You never resolved the root issue nor learned why you had an issue in the first place. If you want to reduce CO2 demand and growth, reduce the light, that's the most sensible method.
Many folks do this and make this mistake.
But if you want to understand and learn how to grow plants well, then looking at CO2 and light critically will help far more than limiting this nutrient or another.
My water seems to need very little nitrates, and little phosphates, so I am raising nitrates by 2 or 3 ppm once or twice a week, and phosphates by 0.25 ppm once or twice a week. I think with my light setup and CO2 I was adding FAR too much ferts, not the slight excess that EI is designed to add.
And you believe that caused algae?
I should be able to induce algae based on that hypothesis using excess ferts.
But clearly I have been unable too.
Even with 3x more light all the way down to 1/2 the light you have.
But....my CO2 is stable and in a good range the entire light cycle.
I can also take a basically well run tank and louse it good and induce about 4-7 species of algae by messing with the CO2. In some tanks, it takes 3-4 weeks, others, a few days.
So what might that suggest?
Since I have switched to my own system however my tank seems to be working out better for me, great healthy growth, and no algae growth. I reiterate, I am in no position to be criticizing you or EI, I was just interested in whether I was getting enough Potassium with my additions of KNO3 and KH2PO4.
again, thanks for your help Tom
It's not about ego or criticizing EI, PO4, NO3 etc for me, never has been.
It's much more about getting to the root of the issues for folks, having them ask the questions themselves, so they have a better understanding.
Then they can help others much more effectively.
Knowing how all the parts work together is much better.
I already know.
I do not need to prove it to myself because I've already done that years ago.
I thought many of the same things folks do prior as well.
But I also know how to set up test to see and question questions.
Calibrating test kits is part of this and using methods that are really accurate when possible.
What is important is that you see how the logic is applied and where your own assumptions might have led you to think something was correct, when in fact, it was something you did not consider and led you to an incorrect conclusion.
I would highly suggest using Gas tanks for CO2.
This will help you far more than most any other thing.
I think many aquarist are scared of messing with anything once they happen by chance on something that is working for them. Not me.
I want to know why something gets algae and why not.
This helps me virtually never get algae in the future and I can really focus on plant health.
That's a lot better than luck.
You also are likely taking better care, dosing more, amd maintaining the CO2 a lot more now than you where then. you have more experience today than you did then also.
These are human factors, and have nothing to do with the methods you seem to imply are better/worse for you.
Many folks try one method, fail, then happen on another, do well at it, and then forever think that other method was bad, when it was just them making newbie mistakes and not taking good care of their tank like they do today.
If I fail at a method I know that works, I go back and try and figure it out.
I know in doing so, I can help my tank be even more stable and have better resiliency against algae and have better plant growth. This way I know I needed to add more CO2 than folks where telling me, or more Traces, or more K+, or less light etc.
We all go through this at some point if you stay in the hobby long enough.
This just helps you to think and learn without as much frustration/mistakes and more insight.
Basically there's still room for improvement in the tank.
Might not be worth it you though.
Many think about it like that, the trade offs.
Get a gas tank, that I know will help no matter what.