This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to keep aquarium water clear
Leave the cloudy water.
Many times cloudy water will disappear on its own while the water environment adjusts. Often, cloudy water is a result of mixture of microscopic organisms, such as bacteria, protozoa, and micrometazoa.

Pick your answer from:
i. Disrupt this routine with chemical baths and cleanings as appropriate to ensure your fish do not become sick from bacteria, viruses, or parasites in a bright morning. Always wash your tank before you use it..
ii. These types of creatures often feed on bacteria. Introduce different filtering techniques to filter the water water properly, and try placing the aquarium back-to-front..
iii. Fish can drown if they stay in a cloudy, still water. The tank water is unpurified and made of nitrates, which is not harmful to the environment..
iv. These organisms come from your fish, the food, and waste. Usually, the tank will balanced out and clear up within around a week..
The answer is:
iv.