W/C with NSW bring ich parasite to the fish?

[Arnata]

Hello
Im planning to do water change with natural sea water (NSW), it is safe to do WC with NSW? Afraid it will bring parasite like ich/velvet to my DT. And going fallow for 76 days again..

 

[Crabs McJones]

It is always a possibility if you get some in the free swimming stage. Another possibility is contaminants depended on where you're sourcing your NSW. Oils, heavy metals, runoff from the land. Make sure where you collect is clean and free of contaminants.