opie, the only thing with these systems is that there is a interinal flow system delivering a steady stream of water to the media, inside there is basically impossable to fix/clean at this point, and if thats not cleaned/killed it will just spread every day

the only way of cleaning would be to
1 disassemble, but not possable with the plants in there
2 flush it out using the pump to circulate harsh cleaner through it, also not possable wit plants in there

This is why my thought was to jump to full strenth peroxide to kill it asap, because with my mold expirence, if you dont kill it quick it wont go down easy. (my last grow i ended up chopping due to mold, when i was cutting it down the whole main shoot was filled with mold, it basically infested the whole plant and reasonably quickly)