thats the worst about them hob filters they have to die sometimes and you never can tell ,thats why i keep 2 small ones side by side . a few weeks ago one of mine sprung a leak and leaked onto a powerbar , it set it on fire and everything was shut down, i was lucky i kept a filter,heater and powerhead on a different bar as well
i think a water change and some carbon will do wonders, any losses???