How long do they last? The fish shop owner said they need to be changed after 2~3 months..
I can understand if the carbon needed changing but bio rings?? Doesn't make sense..
You dont replace your bio media. You mechanical filter ahead of it (and replace the said mechanical filter media as needed) but never replace biomedia ...
Bio is for life. If you ever need to clean it rinse under used tank water only. You should only think about cleaning it at all if flow is heavily reduced.
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