[nfrank]

What is the general thinking on nerite shells dissolving? Is it the low pH or insufficient GH?

Since ramshorn snails do fine in the tank, will the nerites? My pH from AquaSoil and CO2 is ~6.3.

 

[nfrank]

I have had this [shell] growth to occur in lower ph with C0 2 injection and in tanks with ph around 7.4 and our KH is less than 12. .....I added cuttlebone to 2 tanks. The other tanks with these snails received none. Over a period of several months I saw no change in shell structure in the tanks that held held the cuttlebone. I did find that they were often seen on the cuttlebone as to say they were eating the cuttlebone or just feeding from the build up I don't know. I can say I saw no major change in shell growth in the tanks that held the cuttlebone. I do believe foods that contain the right amount of nutrients is one of the major factors in shell growth.

There have been several random posts that seem to suggest that low pH may contribute to shell deterioration. Until i hear otherwise, i am willing to entertain that notion. However, i am somewhat skeptical. I suspect shell problems are associated with low Ca and not low pH.
I found a study that says that
"One important difference between the laboratory-reared snails and the wild snails was that the laboratory-reared snails were fed ad libitum; we do not know how adequate the food supply was for the snails obtained from the wild. Individuals of Lymnaea peregra (Müller, 1774) and Planorbarius corneus (Linnaeus, 1758) reared in calcium-rich water, obtain calcium more from the water than from the food. Individuals reared in calcium-poor water, however, obtain two to four times more calcium from the food than from the water (Young 1975). "

It seems to me that the snails need a source of calcium, but it could come directly from the water. It is plausible to me that the water doesnt have to have high alkalinity. ... just sufficient calcium.... just like we require for good plant growth. If the water has low Ca, then the snails may in fact have to get it from the foods.
In one of my pH 6.5 tanks without loaches, the ramshorn snails are doing really well. So, they are getting enough Ca to build shells and grow to a nice size. To my tanks, I used to provide Ca with pulverized dolomtic lime. More recently, with equal parts per volume of plaster of paris -which is calcium sulfate -and Epsom salt for the Mg.
(I cant figure out why the smiley face appears in the quote!)