Multi-choice problem: Continue writing the next sentence in this paragraph:

How to keep your pond clean
Clean your pump's filters out regularly.
Most filters require cleaning once each week. Usually, cleaning is a simple matter of removing the filter, spraying it down with a hose, and replacing it.

OPTIONS:
[1]. If you notice any signs of issues, like improper cleanings, loss of power, or blockage with the water meter, clean it out. You can purchase automatic filter cleansers at your local hardware store or online..
[2]. However, you should always follow the manufacturer's instructions when deciding how and how often to clean your filter. If you notice your pump leaking or struggling noisily, you probably need to clean it..
[3]. If you do not clean the filter regularly, you may accidentally cause an economic strain on your water supply, which can lead to major health problems down the road. Remove water from your pump after it stops running and replace with fresh water if it is dirty..
[4]. Sometimes, cleaning due to an accident can only get you so far. Decide on a cleaning schedule that works for you and your pond..
[2].