I was wondering if someone could help me. I have a BiOrb 30 tank, and we aim to change the filter every 4-6 weeks as suggested.
Thing is, this is going to be pretty expensive as they are about 6GBP each!
Some online vendors are selling packs to recycle the cartridges, like this one:
Biorb Filter Media Replacement !!!!Pack of 10 !!!! | eBay
Does anyone know if there's any potential drawbacks to doing this? i.e. is there some sort of secret ingredient in the official cartridges that this would omit?
Otherwise, I think I'll just get one more cartridge, and alternate them as it will save tonnes of cash!