Dirty fish tank!!!!!!!!!!!!!!!!!!!!!?

thats just brown algae. It's actually a good sign that your fish tank is cycling properly when you find algae growing. It means that good bacteria is growing that breaks up fish poop. Definitely do not do a 100% water change and you should consider doing just a 25% water change every week, this way the bacteria have more time to grow and stick to things before getting emptied into a bucket and out of your fish tank. And as for the algae, don't worry it will go away once your tank finishes its cycling process.