It is possible to remove the the sponge ring from the cartridge and empty out the carbon/zeolite chips and replace the sponge ring into the plastic cartridge so you can start dosing with salt as Pixie says.
The other thing I would add on the subject of biorb filtration is that the biorb filter is essentially a cross between a air-driven sponge filter and a undergravel filter as it has two components. The cartridge which contains a small sponge for mechacnical filtration and underneath a mixture of carbon and zeolite chips for "chemical filtration". As discussed, the cartridge needs to be replaced strictly every 6-8 weeks and and is the ONLY non-permanent part of the filter.
The"ceramic" filter media (those rough, coarse stones) which forms the substrate, comes with all biorbs and you MUST use it- as it's the permanent biological component of the filter and always stays and is never replaced, only wash in used tank water occasionally the same as any filter media.
Now, as the others say - the presence of zeolite does somewhat impair the ability of the system to "cycle" (it's there for convenince sake and to sell the thing as a low maitenance tank), however you could still have developed some biological filtration as the surface area is vast and with low to moderate stocking (particularly with coldwater fish if at all) it can cycle, and I say can cautiously as I've seen it before in other setups - even with goldfish, but no guarantees. Long-term, a traditional large volume tank would be easier to amture and to manage. I agree with the others, get the water tested SAP and that will help no end in guiding further action