Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to do a water change in a freshwater aquarium [title] Pretreat a bucket of tap water. [step] Get out a clean bucket and fill it with water directly from the faucet. Follow the instructions on your water conditioner bottle and pre-treat the water prior to cleaning.

Ending1: The water conditioner should contain the following ingredients, and the conditioner should also be mixed with fresh water when it's time to clean your tank. [substeps] Chlorine bleach borax sodium carbonate ammonia chloride glycerin [title] Fill the bucket with water. Ending2: [substeps] Remove as much water from the bucket as possible. Feel as if you are getting a bit of a shock from the water. Ending3: The conditioner will make the water safe for your fish by removing dangerous chemicals and metal residue. [substeps] Go ahead and keep two plastic buckets, specifically for your aquarium use. Ending4: [substeps] Usually, you should use natural cleaning methods on the bucket. However, you will also need to use your own tap water to clean your fish tank.

Answer format: ending1/ending2/ending3/ending4