Wondershells, and the mysteries of GH & KH, & pH

[rogierfvv]

I've come to use wonder shells steadily. But I seem to be more confused about water chemistry than ever...

In my 29G it seems GH runs up way high, off the charts, but KH I have trouble keeping above 5 or so. Every morning my pH is at 6.10-6.20, and I add a 1/4 tsp of Seachem Alkaline buffer, which tends to put me at close to 7.0.
By comparison, my other tanks for some reason seem to be more stable. My 5 gallon, which is essentially an invert refugium stays steadily at 7.10-7.20, and my 10G shrimp tank needs an occasional pH boost maybe once every week or two, but mostly stays close to 7.0. It is just this 29G tank to which I am now adding a 1/4 tsp of alkaline buffer almost every day...

What could be going on? 

A related question is about Black Mollies. I put a few in this tank, and that is one reason I am somewhat concerned about seeing pH stabilizing a bit higher. Still, the Black Mollies show no sign of discomfort, and in fact they have had babies already. Is it that with the wonder shells indeed we should not worry about the pH so much? 6.15 just seems very low...

[Carl]

Wonder Shells do little for KH, especially if acids are being introduced by whatever means to the aquarium (despite the claims by the original manufacturer).
For one they contain no carbonates or bicarbonates

Mollies benefit heavily from the use of Wonder Shells up to full dose.

Other tanks, such as Shrimp, Wonder Shells are best used at only 1/4 dose, which will also restrict higher GH tests

I would also look into what might be creating more acids in these tanks where the pH is low, as this would be the common denominator, not the Wonder Shell itself

Regards;
Carl

[devonjohnsgard]

I would think if the KH is 3-5 it would stabilize the pH. Are you trying to increase pH or just stabilize the pH you have from the tap? There could be some driftwood etc that leeching a lot to bring down pH or over use of peat moss? Best is to just stabilize the pH from the tap.