sand scratches?

[Bethany]

I have two dojo loaches, and they have whitish spots on their bodies [it's not ick, one had it before, but it's not like that].

I got sand two weeks ago, and they love it, but these marks started showing up. I know they aren't bite marks from other fish.

I did a bit of a water change just to give them some fresh water. Just wondering if the sand would have scratched their skin

 

[Bethany]

and they're acting normal, and no other fish are affected, so this is all I can think of

 

[Finalfire9]

Adding sand can change your ph lvl sometimes.. but it will restablize after 30days or so.

 

[kydsexy]

do you have any pictures?