Rocks in Convict Cichlid tank

Question
I have a 29 gallon tank in which i will be putting 5-10 convict cichlids, possibly including a breeding pair. My question is about the rocks i have gotten for my tank. First, i washed them off really well and put them in my tank and the water became very cloudy, so i figured if this cloudiness went away they would be fine. It didnt go away completely so i boiled them. When i boiled the rocks, they gave off a smell very close to oysters being cooked, and in parts of the rocks, they chip pretty easily. The rocks have fossils of seashells in them so i figure they must have salt in them. However, my teacher which im getting the fish from has a huge cichlid tank with 50+ in it which was formerly a saltwater tank. The cichlids are doing fine in the tank with even with the higher salinity, and a hermit crab is even able to survive in the tank, which must mean its pretty salty. So my final question is what should i do to make sure that the tank will be ok for the fish? Should i find new rocks or will these be ok?

Answer
Hi John,
Although convicts can live well in a PH of 6.0 -8.0, I think that maybe the rocks may be giving you a higher PH...I would not trust those rocks, especially with that smell, and the fact that they chip, and make your water cloudy.  I would change the rocks...if you are living close to a river, you will find some beautiful rocks there...it it always best to boil the rocks first.
Hope this helps
Lynda