sWozzAres said:My tap KH varies from 6 to 13 so everytime I complete a WC I have to reset the DC. This involves alot of effort in tweaking and monitoring and by the time you've got it sorted, it's time for another WC. Imo this makes DC impractical. At one end of the scale your in real danger of killing your fish and the other, inducing algae.
Since EI is a proponent of the "no test kit" methodology, I often wonder how many other people have the same problem and aren't even aware of it.
Well, EI says nothing about test or not to test CO2, nor light.
I'm no fan of the DC's, but I also do not fall for pH controllers for the same reasons with KH changes and influences on that parameter. pH meter at least have a much much higher accuracy concerning pH measure, DC's have 3 different measures basically.
In the past, we used pH meter(not controllers) and set it at the assumed pH/KH combo. From there, we'd adjust the pH down slowly and methodically, setting it another 0.05pH units and then watch and observe fish, plants, algae. After 2-3 weeks, we might adjust it down a tad more till we see nice lush growth and no algae.
You can also do this with a needle valve, turn the valve say 1/20th more CO2 gas and watch each time.
By doing this slow and step wise, you hit a nice CO2 sweet spot and can tell what subtle changes look like and thus...can respond appropriately in the future. This is much more valuable than mere feast or famine CO2 dosing.
This same slow adjustment can be applied to EI as well, starting at the higher non limiting level downward and then bump back up to the next highest level once you find a negative effect due to limitation. No test kits for either.
Lighting is a one time typical test and then that's it/done.
So it depends on how you approach it, no testing is not really the goal, we use plants, fish, algae as test kits in all cases(they are much more specific to our goals than ppm's etc really).
In both cases, no test kit is really needed.