[Derelique]

Naive question, but what effect, if any, does standard water column and root tab dosing have upon hardness and alkalinity?

I'm trying to maintain slightly soft acidic water in my tank but my water seems to be harden than I had expected it to be and there aren't any rocks or other things that should be contributing to hardness and I'm just using flourite substrate.

 

[Sharkfood]

Not much. Dosing Mg and Ca will raise your GH by some amount, but it's very tiny unless you are dosing them specifically to boost GH.

 

[Derelique]

Okay, reading into this further http://rexgrigg.com/waterchem.htm it appears that a gH of 3-15 degree and a kH of 3-12 degrees is fine. So as long as they're each at least 3 but not too far above 3 then the plants won't be limited by calcium or magnesium but the water will nevertheless be soft.

If kh is too low you can add baking soda (Sodium bicarbonate). And if Gh is too low then you can add epsom salt and calcium chloride (separately). It seems the use of some calcium carbonate (crushed coral or aragonite, and some magnesium carbonate, (dolimitic lime), will accomplish the same thing as well.

 

[Sharkfood]

You could run into a magnesium deficiency, but calcium is very unlikely.