Fiji rock cause high phosphate? Never heard that. I have 45lbs of fiji in my tank.
The rock from the fish store should have no die off. The rock from LR
.com should have very little die off. You need die off to start the cycle. That is why most put a piece of raw shrimp in the tank and let it decompose.
The stuff from hirocks will be seeded by the other LR
Easiest thing might just be to add all the rock when you get it and see if you get an ammonia hit. Add some hermits and then feed the tank. Make sure you have an establiished bacteria bed before adding fish.
OR add the LFS
rock and the hirocks. Then add a raw shrimp and go through the cycle process. When it completes, order you LR
.com rock and go from there. The LFS
rock will not have the life on it that LR
.com rock has. Most don't want to go though a full cycle with good rock because some of the life won't survive.