I'm confused. Was the gravel that you recently added to your tank ever in a saltwater tank? I understand it was dry before you rinsed/added it. But if it was ever in a saltwater tank, I'm thinking its possible you did not rinse/clean out the gravel well enough before adding it to current setup. But thats just speculation, the gravel might not have even been the killer.
There could have been large temperature fluctuations while moving them. Could be that your heater got turned to a different setting after moving the tank. Heater could be broken. Maybe the buckets you used to transfer the water had something bad in them....could be anything really.
If you had the ac50 filter turned off for an extended period and turned it back on without emptying the water in the back first, you could have poisoned the water (im not real sure on this, but I thought I remember reading somewhere that the beneficial bacteria starts to die without water flow/etc, and when the bb dies they turn toxic.)
There could have been large temperature fluctuations while moving them. Could be that your heater got turned to a different setting after moving the tank. Heater could be broken. Maybe the buckets you used to transfer the water had something bad in them....could be anything really.
If you had the ac50 filter turned off for an extended period and turned it back on without emptying the water in the back first, you could have poisoned the water (im not real sure on this, but I thought I remember reading somewhere that the beneficial bacteria starts to die without water flow/etc, and when the bb dies they turn toxic.)
