Question regarding freshwater to saltwater swap

[MichaelsLilGray]

Im changing over my current freshwater 125g to a saltwater tank... i have about... 100lbs of sand and i would like to keep it in there and line my current sand on top of it. if washed out would the sand in the fresh water tank be able to convert over, over time? or do i need to just eat the loss and start new?

 

[roka64]

Yes, it will convert over. If you go that route, make sure you wash very well as the sand gets all kinds of nasties in it.