Hey Lou I have to ask.
If you had a meter that would provide an absolute reading of NO3 & PO4, how would you use that information?
And I get the wanting to understand water chemistry.....but I am curious what you are hoping to gain in relation to defeating algae?
Simply put, it makes me feel better knowing what is actually happening in my tank and the error /resolution of these cheaper test kits that are available does not make this possible to the degree of accuracy I would like.
I compared my ATI PO4 test kit against my Hanna photometer (left over from the reef tank days) and could see how inaccurate trying to read / interpret the colors were using the ATI ! I was way high on my PO4 level using the ATI.
The Salifert NO3 wasn't giving me the accuracy I wanted until I diluted the solution 9:1 in order to use the lower range high resolution technique that test provides though, it's still hard to determine a 5 ppm change especially at the higher levels required in planted tanks.
Given that; micros, light, CO2, K, GH and KH are at what seems to be standard levels (given what I derived from being on this website for a year) then the only other controllable nutrients I can add to my tank is NO3 and PO4.
From what I understand these are the only other two main nutrients that effect plant growth and subsequently algae growth. So why wouldn't I want to know, in an accurate way, what they actually are?
I want to be able to dose NO3 and measure the amount of NO3 that the plants takes out so I can measure and determine the uptake rate. The affordable color based test kits that I have been using aren't accurate enough to make this possible. This ppm change is in the "noise".
Once I know the uptake rate I would be able to dose the tank accordingly. I like to be scientific (accurate) about my tank chemistry. I want to know what my PO4 and NO3 levels actually are and dialed in the way I think they are (it's a control thing).
It seems that lot of people are happy with just calculating the dose adding it to the water and calling it a day. But how do they know with high accuracy what the plant uptake is? I want to know what the rate that NO3 and PO4 is taken up after dosing.
For example if I increase my PAR level over the tank I can actually measure what the increase in NO3 and PO4 uptake is and adjust my dosing thus, preventing an algae outbreak down the road from depleted nutrient levels. Don't we want to know and measure with high accuracy what are PAR level is?
It's just a personal preference. It provides me with more information. It provides me with more control over what's happening.
I guess working in a lab environment all my life has contributed to my "type A" approach to my new hobby. I get all twitchy when I can't measure stuff 🙂.
It makes me feel better to have a much more accurate way of knowing what's going on. To me it adds to the fun factor and in turn adds to my enjoyment of my system.