Fish Flashing

So , my trout are flashing a little . I've read I should salt to 3 ppt. I've ordered a refractory meter, but won't be here for a week. i'd like to get some salt going sooner. Can some one recommend an amount to add to start with . Is one g per liter sound right ? I have approx 3000l water total system (2 -1000l FT and 2-500L ST) So, my math says 3000g or 105 oz or 6.6 lbs ?
Thanks
Sean