Yes, it's good to have, Steve Dixon and I did some Gh work back in the 1990's as the SF tap water is notoriously low (0 to 20ppm).IUnknown said:I think one good thing with this method is the information on Ca and mg. I've got the test kits coming in a couple of weeks, so I'm not sure its my problem, but at least the information has given me another place to look for answers to my leaf curling/stunting problem.
He added Mg and Ca and after seeing my tanks and tap water switched to adding more GH.
There is an old article on sfbappas site to this effect with very soft purer waters.
Up take rates can be used and useful for Ca/Mg if you plan on adding "just enough" but I see no utility in adding just enough or testing for it unless you know there is an issue. I used a wide variety of tap waters with enormous ranges over the years, I've never found found issues unless the Gh was too low.
So adding plenty to never have it become limiting has been much easier than testing.
I can add just enough NO3 to a tank also, but why?
Why walk this fine razor's edge? Does higher Ca/Mg cause algae? Hurt plant growth, if so which species? I have no seen any GH related issues at high GH in any plant species, KH I have seen with 2-3 species better growth at low KH's, but not GH's. I have plenty of dosing experience with Mg as do many being part of the PMDD program.
Neil and I discussed Ca for many years, he has very soft tap water as well.
I've found plants do much better with higher GH's.
Same thing for KH, but there are 2-3 species that seem to grow "better" at lower KH's.Most plants will grow better as there is an ample supply of DIC Carbon.
This makes me question the utility of GH measuring unless you have a gaol of minimizing the additions of Ca/Mg for some reason.
Can you better pinpoint the rates of uptake and predict the ratios? Sure, not sure why you would find that useful though nor gain much from knowing that.
Testing is great and all, but to what end? You can rule it out I suppose, but I've said that years ago if it was in excess and high enough, 50-100ppm or so, then you don't have much to worry about. If you still suspect something, add a little MgSO4 as Ca is virtually never in excess to Mg in any tap water.
If you use RO, then you neeed to add all the KH/GH components back, that's a PITA but too bad once you get use to it. You add 1 tablespoon of CaCl2 and 1 Tables spopon of Baking soda or Potassium carbonate etc, 3/4 teaspoon of MgSO4 to your tank after each water change and then you are done, it's standard.
If you want to push the water changes and not do them....then this information begins to become useful and you'll still need to test......
So there are trades offs..........
I'm not sure these are worth all the testing and seeing how far you can go without messing things up at higher growth rates.
You can test to check to make sure Ca/Mg do not louse up and become limiting.........
But after testing and all and calibrating the test.....it seems easier and cheaper to do a water change.
Why avoid the water change? Seems like a self imposed barrier to me.
I've tried as have many others with good test kits(All lamotte and Hach) to try and add only what the plants will use and avoid water changes. I know the mentality of it and results. It's 3easy to do with non CO2 methods and as you increase the light, CO2 you increase the uptake rates of the plants.
Edward is entirely correct about each tank having a unique uptake rates, plant species etc. Uptake rates in a tank will less/more than another.
Plant specific uptake rates also play a huge role.
But these rates are not a problem nor need monitored if you add a standard solution back into the tank each week and do the large water changes.
All that monitoring cost you money, time and work.
Water changes removes many of the unknowns, need for testing in the first place(something that is very tough to get folks to do for even the most basic things such as pH/KH, many still don't measure KH routinely)
One area I would suggest that would be very useful using PPS, monculture of specific plant species.
That work would be useful, in addressing plant specific issues and appearances without infuences of other plant-plant competitions.
But not everyone wants a single species plant tank