After the last clean we did, both L and I noticed that the tank was a bit murky. I just thought it was bits that had been stirred up from the clean and thought it would settle after a few days as it normally does. A week later and the water was still looking murky, so I decided I had better investigate. To my horror I discovered that the pump had stopped working, which meant no filtering was happening and none of the heated water was being circulated around the tank.
After dismantling the pump I found that some dirt had got clogged around the propeller base, preventing it from turning. Once cleaned it started working again, but not at its full capacity. The tank is up and running again. I am going to give it 2 days running to clear out the murkiness and then we will do another water change.
What I have learnt from this is that if you see something out of the ordinary in the tank, you should investigate as soon as possible to prevent any disaster. I have also realised that even though the tank is full of fish, the amount of water in the tank is enough for them to survive without a pump running, which is good to know in case there is a power failure or the pump breaks again.
