I went out of town for 4 days and finally had a chance to use my Tetra Holiday/Weekend sticks. They can supposedly feed fish for up to 30 days. I put 3 in a 29 gallon tank with about 15 fish. When I came home the sticks were pretty much all dissolved and there was no yucky residue and the water was clear. The more days you are gone the more sticks you put in. The fish all look well fed and active. I highly recommend them!