Always Wise To Have A Pump And Airstone.

[WILDER]

Many uses meds, hot weather, and if your filter packs in and you don't have a spare one.

 

[three-fingers]

True, but a cheap air powered sponge filter is much better to have than an airstone.

And even better than that killer combo is a spare filter .

I'll always run two filters on my tanks, so if one breaks when I'm away, the worst that will happen is a mini-cycle - which my plants can generally take care of .
If one filter AND my lights were to break, then water changes can easily deal with the mini cycle .

Anyone else run two filters for this reason?

I know lots of people run two heaters...but I don't see this as a main concern since the waters not going to drop below room temperature anyway, and lots of tropical fish deal with lower temps than that in nature.
But I guess it depends what species your keeping .

 

[Ferris]

I run at least 2 filters on all my tanks. This always gives me a safety net and allows me to completely blitz 1 filter every so often without upsetting the biological balance.