Maybe the question in the title is simple (=stupid) and the answer is 'simple No' but I have the urge to ask.

Some background, I have an aquarium which I use RO water and I use some portions of $\ce{KHCO3, MgSO4, CaSO4}$ to raise my GH and KH and in result, I get also an amount of $\ce{K, Mg, S, Ca}$ + (bi)carbonates in the water in a specific $\pu{ppm}$ quantity and ratio between them which I want to keep it stable.

Still, after the additions of the compounds above, I get something like 1 KH, 3 GH and pH of 6.4 but I need to raise it around 7.

Is there any other way to do it without another compound? (preferable no baking soda or soda ash)


  • 2
    $\begingroup$ Try replace part of KHCO3 by K2CO3, keeping the same total amount of K. The needed ratio is best to determine experimentally. $\endgroup$ – Poutnik May 16 '19 at 13:10
  • 1
    $\begingroup$ Strontium carbonate, maybe? Not sure about the effects of $\ce{Sr^2+}$ on aquarium inhabitants... $\endgroup$ – Todd Minehardt May 16 '19 at 23:38
  • $\begingroup$ NH4OH, which is given off by aquarium wastes, anyway. $\endgroup$ – DrMoishe Pippik May 17 '19 at 1:13
  • $\begingroup$ Adding ammonium ions to an aquarium water is not good idea. $\endgroup$ – Poutnik May 17 '19 at 4:18

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