sick snails

[anabanman]

My misc snails ( red rams tha like ) are turning much lighter , my trap door is sleeping more these days , and my mystery is much paler yellow . A friend from the club is having the same problem in his large number of tanks . We think its a calcium defeiciency. Do you guys know ? My water parameters are exact for my gouramies with nitrite n nitrate well under control . The only thing ive changed in the last few months are the addition of more plants .