Soak food in garlic guard and Feed them .
As long they are eating they will be immune to ich .
You must be stocking too fast .
Set up a quarantine tank so your main tank won't get ich .
Post some pictures of your tank
Is there sunlight during the day that shines to your tank ? Sunlight is the worst that causes algae .
You can also scoop out day by day portion by portion then top up with new sand to see if it helps .