What is this
I have noticed an outbreak of this in my 40 gallon saltwater tank. the tank is only 2 weeks old. I have used the dead shrimp test, fish food test, and now have a fish in it. All test had the same result; ammonia 0, nitrite 0, nitrate 5. I have 5 cortez hermit crabs, 3 nassarius snails, and 3 astrea snails.
What is this? How can I keep it from forming?
I will post pictures