i have a filter that contains bio wheels and 2 filter things how often am i to change the cartriges

its been awhile since i use a marineland hob but the bio wheels are good for a long time. if there not damaged there fine. and the cartridges i beleive should be changed monthly if i remember correctly.

please check the contents of the cartridge. there are some
cartridge that can be use as holder of other media. just remove
the old contend and replace it with foam or synthetic fiber,
it works for me.

Thax 4 the info Mod !!

Wow didnt know i could use foam or other materials for filtration thanx Paul:huh:

filter media are basically have different purpose:
1) to remove and hold dirt, waste, and left-over foods
2) serve as host for good bacteria that process ammonia and nitrite
3) collect and hold some minerals in water

if you will analyze, how could a ceramic ball help in filtration?
by holding and hosting good bacteria in the system.

thus anything phorus could serve as alternative as filter medium.

For the bio-wheel filters, you dont really want to change the wheels unless you really have. The wheels is where all the beneficial bacteria live. As for the cartridges. The rule of thumb for filters like this is about 2-4 weeks for changing them.