What do you use to raise KH, Sodium Bicarbonate(baking soda) or Potassium Bicarbonate
Many sources state that potassium bicarbonate is better because the plants need potassium, but not sodium. Some sources will go as far as to say that sodium bicarbonate is harmful to the planted aquarium.
But it seems to me that using potassium bicarbonate to provide KH in RO water is not without its own problems. When combined with the large addition of potassium contributed by GH boosters, and in some cases plant fertilizers, it becomes VERY important that we suppliment nitrate without adding additional potassium (i.e. no potassium nitrate). I say this because when potassium is dosed into the aquarium at much higher percentages than calcium and magnesium, the uptake of those later two nutrients becomes inhibited. Sure I could just raise the GH more with a homebrew GH booster that does not contain potassium, but I would rather not for the purposes of breeding soft water fish. I would greatly prefer to simply use calcium nitrate and magnesium nitrate to dose the nitrogen and balance the large amount of potassium added through the potassium bicarbonate buffer and GH booster.
Pure Calcium Nitrate and Magnesium Nitrate, are difficult to obtain, however. Both are powerful oxidizers that can be used to create explosives, and therefore the added liability to merchants who would choose to sell and ship the them is usually not worth the risk. Less pure versions sold as calcium nitrate fertilizer are almost always NOT pure calcium nitrate. They are instead blended with ammonium nitrate. This form is characterized by a 15.5-0-0 +64%Ca forumuation and a molecular formula of 5Ca(NO3)2.NH4NO3.10H2O. The pure calcium nitrate formulation without ammonium nitrate is much harder to find, and is denoted by: Ca(NO3)2.3H2O (12.8-0-0 + 18.3%Ca). Now why is this so important to know? Because Tom Barr in his article about the EI method states that ammonium is the one nutrient which can spur rampant algae growth. So it sure would be nice to find pure calcium nitrate and magnesium nitrate fertilizer. With these we would be better able to avoid the potasium/calcium/magnesium imbalance and reduce the need to add magnesium and calcium sulfates. Sulfates certainly should be present in some amount in the aquarium, but in excess can create bad smells (via hydrogen sulfide gas).
So, how many of you use potassium bicarbonate in the first place, and if so, do you agree that using magnesium and calcium nitrate to suppliment nitrogen would be an improvement over using potassium nitrate? I am interested to hear your opinions!