On a side note the API test kits are notorious for showing zero ammonia as 0.25 so you may not actually have ammonia present in your tank. Do not use the prodobio stop ammonia, it will inhibit the cycle, not help it. You may want to add an ammonia source, using either pure ammonia or a couple of dead raw shrimp to induce an ammonia spike. If you go the ammonia route use pure ammonia without surfactants or perfumes (available at most hardware stores, I got mine at Ace Hardware). To be sure the ammonia does not contain surfactants shake the bottle and if it bubbles up like dish soap it has surfactants in it, pure ammonia will not have bubbles. To raise 100 gallons of water from 0 to 2 ppm ammonia you would need to add 0.8 grams (8 ml) of standard 10% pure ammonia.