Revamp old tank

[reefman141]

Lost live stock due to velvet ,starting over , doing 50% water change, pelace filter media,which is bio wheel pads ,got skimmer ,filter sock and replace all new sand bed, my question does it need to be. Cylce again keeping live rock 3 yrs old do i need to add more bacteria ,whats my pro and cons?

 

[MushroomReefing]

You still might have velvet in the tank system. I read somewhere that velvet will stay in the tank system for up to 5-6 weeks. You most likely need a fallow period and go fishless for quite some time to break its life cycle. It cannot survive without a fish to host.

All the best and take the safest approach without risking any future livestock!

 

[Mr. Mojo Rising]

Add some ammonia and see if it's processed quickly into nitrate, if yes then the rocks are still cycled, if not then add bacteria and continue the cycle until its done. IMO