Edward, could you explain this a little more. I've been using baking soda for a couple years and was never aware that it could cause any problems.Edward said:Using baking soda to raise KH is not the greatest idea because the water will end up with lots of remaining Na making it difficult for plants to absorb some nutrients.
Edward
I guess it depends on how you use baking soda in your tank. I've been using it without problems for quite some time. I think it's safe to say that if you use baking soda for your makeup water only and not to put back what the plants have removed in the existing tank water, it is impossible for Na to accumulate further than the concentration in the original makeup water. Evaporated water is replaced with pure RO/DI so again, no accumulation would occur. I can't say I've ever noticed such a drastic drop in KH from plant uptake, it's definetly not measurable in my high light tanks that receive weekly water changes and slightly apparent in my lower light tanks without CO2 and monthly water changes, but nothing big enough to require further NaHCO3 to be added to the existing water, I guess that's the big difference here, if your KH drop is big enough to require supplemental KH to existing water then you'd want to make sure your source of KH is pure. Perhaps using some crushed oyster shells in the filter would help balance things out and maintain steady KH levels between water changes.Edward said:gpodio,
Baking soda is NaHCO3,
if Na accumulates over time then plants won't be able to take up nutrients at available low concentration levels. The nutrient dosing will have to be elevated to overcome this problem and therefore the algae grow may be also increased. Same theory applies to excessive K, Ca, ...
Na won't build up if water changes are done periodically. But then, not everyone enjoys wasting time pumping water all the time.
There are healthier alternatives to baking soda. Run your RO water over fine gravel CaHCO3 to get Ca and KH, or over dolomite CaMg(CO3)2 to get Ca, Mg and KH.
