If you're going to use hyposalinity rather than copper, you need to put the fish in the tank with normal salinity to begin with and gradually bring it down. They can survive the low salinity just fine but you have to ease them into it. If you just dump them from say.. 1.023 to 1.010 in one shot, it'll likely shock and kill them.
I personally prefer copper since it's much easier but hypo is supposed to be safer in the long run when you do it properly.
And if you want to add a HOB filter just with foam or filter floss in it that's a good easy way to get large particles out.
You also want plenty of stuff for them to hide in in the tank to reduce the stress. It doesn't have to look pretty so you could just use some old tacky plastic decorations if you have them or just get some pieces of PVC pipe.