Questions on gh and kh...

[Lonewolfblue]

My question has more to do with healthy plants than adjusting gh and/or kh. Was just wondering which is more critical to the plants health, and what should the minimums be for healthy plants. I've read that for healthy plants, the gh should be at a minimum of 5-8 degrees. Is that true? Reason I'm asking is because both my gh and kh are 3.34 degrees, and was wondering if I should be bumping something up along with my ferts. What are your thoughts on this....

 

[Jchillin]

My gh/kh is just about the same as yours (I didn't get a fractal measurement with my test kit)

I did notice I was almost devoid of Ma and Ca, which led me to using a bit of Seachem's Equilibrium recently. This observation was made only when I realized my snails were losing color in their shells. I really did not observe this to be a problem with the plants but, it made lead to more plant health.

 

[7Enigma]

All depends on plant growth rate and your frequency of PWC's. I think 1degree is around 17ppm? Both calcium and magnesium are macro's that get used up fairly quickly in a tank. My GH is around 10 degrees, but if I had to raise GH I would proabably put mine around 6-7 to ensure those nutrients were never causing a deficiency.

It's also a good idea to get a water report with such a low GH since you might only have a small amount of either Ca or Mg.

 

[Lonewolfblue]

Actually, if anything, it would be calcium, as my CSM+B solution contains extra iron and magnesium. And the think is, even when dosing the extra magnesium, my levels don't change. Still stays at 60, and I do put a bit of magnesium in the solution.

 

[czcz]

Maybe the test is broken. What happens when you dump MgSO4 into a glass and test? Trust the plants more than the test regardless, of course.

I'm of the opinion its easier to grow lots of plants in low KH. But I grew lots of stuff in dKH 5.5-6.0 and in many ways prefer not messing with KH.

I do not find target GH important. I use RO/DI mixed with tap in one tank to get my GH near or lower than yours. I do not dose Mg but sometimes increase Ca with no significant effect. (I have dosed Mg at ~10ppm levels and blindly with no appreciable increase in health). So I assume I have both Mg and Ca in tap and move on.

That said, some people whose plants I envy go to great lengths to target 4:1 ratios for Ca:Mg. As a general rule they end with the GH range you're considering targeting. One day I may mess with GH Booster/Equilibrium to reconstitute RO/DI and see what happens.

Based on this, I think of GH as more important for plants, only because I doubt one could grow plants with no Mg or Ca while I think they could with no KH. But I don't think either is so important if you have Mg and Ca for the plants and stable KH for the fish.

 

[Lonewolfblue]

That is pretty much what I was thinking, that gh played a little more of a roll than kh. As for me, for now keeping things as they are. Just wanted to know what you just covered. Thanks agian....