Rea filstar xp1, maintenance

by Justina
(Huntsville, al, USA)

I have an Xp1 filter and I do the regular changes and cleaning needed. But I'm not sure how long I have to wait to replace the things inside.
I know I must replace the carbon, but how long between replacements?
same with the whiteish tanish rocks (name escapes me) do they get replaced or not, if so how long can they stay in the filter.
I've also heard that the bio stars need replacing every 6 months, but im unsure.

thank you for your help

A: Most chemical media (carbon, zeolite, etc) lasts about a month depending on the bio-load of the filter. BioChems stars we recommend replacing 10-20% every year. Foams don't need replacing unless they start to collapse and/or shred. Usually 6 months to 18 months. The micro-filter (white) usually every month to 6 weeks.