No clue on the clam. I have a Maxima and he attached to a rock and is just growing. Is your clam on a rock or in the sandbed? If he's in the sand you way want to try to get him on a rock, as they like to attach their foot to one. Instant Ocean salt has been recommended to me before, and has a higher alkalinity and a lower calcium content than oceanic. Try a 1/2 gallon water change everyday in your nano. I'm going to guess that if 1/2 gallon is too much, you'll see it real quick. Have you done any other mods to the cube? ie: overflow cut, taken out the material in the back, upgrading pump, etc?

And yeah, I gave Kold Ster Il water a try, and it was headache after headache. Stick with Ro/Di which you can get at the MAAST sponsor Aquatek.