Not sure about white eggs.

Silver eyes are good use a flashlight to see them reflect. You could just turn everything off on day 7 and wait 45 mins see if they hatch and collect them with a cup to put in the fry tank. Keep the tank dark use a flashlight they will come to the light, then you scope them up. It does take awhile. That is how I do it. If they don't hatch that night repeat the above the next night. Good luck!
