KH GH and Salt? Help needed from chem gurus

[illiswiller]

GH increase b/c of Salt? Anyone?

OK - let me try again:

My GH went sky high recently from 50-75 to over 200 ppm.
Could salt have caused this? I'm treating the tank w/ 1 tsp/gallon.

Or could it be the aragonite that I put in the filter to raise the KH?? However the KH hasn't risen this whole time and is still at 20-40 ppm.

???? HELP - anyone?

 

[illiswiller]

Please?

 

[OrionGirl]

What kind of salt did you use? Aragonite will increase KH, but only in low pH--otherwise, yes, it can increase hardness.

 

[RTR]

Plain "salt", sodium chloride/NaCl, does not register on GH or KH tests. It does show up quite well with TDS tests.

 

[illiswiller]

Thanks guys - I used Jungle freshwater aquarium salt and Non-iodized Morton. My pH is 7.0 w/o the CO2 turned on.

So why did only the GH increase and not KH with the aragonite?

Is my water chemistry completely messed up?

I'll try to get a TDS kit this weekend....

 

[RTR]

Perhaps your tank is burning out the KH through normal nitrification. The GH is not affected by that, so remains. Is your stocking density high? Do you do substantial water changes?

 

[illiswiller]

Thanks RTR
Nope - I'm pretty confident I'm understocked. It's 42 gallons and has 2 young angels, 2 dwarf gouramis, 4 danios, 8 cardinals and 2 cories. I'm waiting to stablize the pH/KH to get a pair of rams.

Since it cycled my nitrites have never left 0 - and I do a weekly water change between 10-20%. The tap doesn't even register KH when it comes out at the sink. The first drop turns color. I have never been able to get it up. Its frustrating b/c I need CO2 for the plants but can't get the KH up.

Don't know why the GH is so high now - must be the aragonite.

Any suggestions?

 

[happychem]

It is the aragonite. Aragonite is Calcium carbonate (CaCO3). There will be plenty of dissociation naturally occurring at pH 7.0. With nitrification lowering pH, and therefore consuming CO3-- for all intents and purposes, there is an increased forcing on the equilibrium:
CaCO3 <-> Ca(2+) + CO3(2-)

By consuming CO3(2-) the above equilibrium is pulled to the right slightly. Ca(2+) contributes to GH.

Adding CO2 will further contribute via the following reaction:
CO2 + CO3(2-) + H2O -> 2HCO3-

 

[RTR]

Also increase your water change frequency and/or volume.

 

[happychem]

Agreed, aim for about 50% weekly. 2x30% is the same as 1x50%.