The Estimative Index of Dosing, or No Need for Test Kits

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Tom Barr

Staff member
Jan 23, 2005
smik;41873 said:
Hi Tom.
Why when there is uptake rates 0,2-0,6 ppm PO4 / 24 hours it is 1.4 -4.2 ppm a week. The EI is added to the tank 4ppm PO4 3 times a week. It is 12 ppm. The smaller dose was not sufficient to cover the consumption of plants?
I am sorry for my english I am use google translator. :)

Because it's not about consumption and merely adding just enough to make up for the lost. It's about maintaining a reasonably high target range(not a particular ppm).
This is virtually always more than what the plants might use.

So we add more than the uptake of the plants.

The higher ppm's allow more uptake and stability.
Why do hydroponic solutions such as the standard Hoagland's solution use 210 ppm of NO3?

Re: Hoagland's Solution

This is old news.
I think someone is trying to pull the wool over your eyes and suggesting "less is best", or "just enough and no more"

This is not what is done in every other type of horticulture:rolleyes:

All (95-98% of all aquatic plants raised for aquariums use a similar hydroponic solution, we cut the %, by 1/5th for submersed culture for fish etc.

But fish are the main reason, not because of plant demand.

Plants adapt to various ppm's using different affinity enzyme systems, so they need less energy to take up nutrients when the nutrients are at higher ppm's.
This is not theory(adaption to various ppm;'s via affinity enzyme uptake systems), this is demonstrated fact in horticulture, in hydroponic systems, in crop plants, in various nutrient and fertilizer test.

I doubt google is going to translate this correctly for you.
Hobbyists need to learn a lot more about how plants grow, and adapt to nutrients before they will understand it.

I try and keep it simple.

But folks wnat to know "why" I tell them.

Tom Barr

Tom Barr

Staff member
Jan 23, 2005
nipat;41878 said:
Tom's PO4 range is 1-3 PPM per week. He suggested a member in this thread to dose 1-1.5 PPM
of PO4 per dose.

And let's look at this instruction (for a 20 gallon tank):

1/16 TSP = 0.3 gram

Adding 0.3 gram of KH2PO4 to a 20 g tank = 2.77 PPM of PO4

It will be lower by half if you choose 1/32 TSP.

You can also modify EI to suit whatever range you think works well fro you.
It's just a concept, the ranges I suggest do work well over time, but they might vary, I like adding 5ppm of PO4 3x a week personally.
10-12ppm of NO3 3 x week and .6ppm of Fe as the proxy for all my traces 3x a week.

Other's might prefer more, less etc.
Some might want to add just enough for make up, to reeuce their water change frequency of %.

That takes some good observations, and being careful, but most can do this with some time and experience.

Does not imply continued use of good water changes are deterimental, unneeded, get nothing in return for them, or "Bad", nor are they all that wasteful as many imply as well:cool:

Water is pretty cheap and easy to change.
High light cost far more and causes more issues for maintenance.
Why don't those same whining cry babies complain about folks using high light?

Likely because it is really NOT about waste and "using just enough".
If it really was, then they'd focus on light and be critical of people using more than "just enough". It's like the tail wagging the dog, they put the end before the start of where growth occurs.

It's a backward logic focusing almost everything on nutrients, not that much on CO2 and even less on lighting. Then I get some BS lecture about sustainability.

ADA also suggest large weekly water changes, so do 95% of the breeder's, Discus, etc etc..........even the far more scientific reef folks, who test with far better methods and equipment still do those water changes every month.

We can avoid water change saltogether if we chose a lower light, non CO2 method.

As you can see, low light, and no CO2.............then what about nutrients then?
You see?

This puts the dog at the front, and then the dog wags the tail(nutrients).

Also, I really see few folks who complain about nutrients in the water column, even bother to test in sediment or use enriched sediments.

If they do, many often assume that less is better in the water column also.
This is not different than the water column dosing as well claiming that less is best.

We can add nutrients at high non limiting levels in BOTH locations and get a very robust system. then we can chose lower light and good CO2. We can still dose moderate amoutns to the water column, do good size water changes every so often, but more reduced dosing and water changes if we chose.

There's a lot more flexibility than many who claim their dosing method is "best".
They really are not that different, some are leaner, some add the nutrients in different locations etc.

Most like to suggest they know algae and that their method cures it.
You must include light and CO2 and nutrients, not just nutrients, if you are going to focus on plant growth.

Algae is a separate question and issue.
Generally a result of plant neglect.

Tom Barr
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