Well two questions . Just brought a second hand juwel 70 tank.
And we are a bit vauqe on the changing of the filters and no instructions. And can you use two filter systems at the same time , eg under gravel and the corner spong filters i have with the tank already.
hi jeffrey on the juwel filter system u have 4 different types of filtration at the bottom u have ur blue sponge pads a fine and a course, now these only want changing when the sponges stop springing back (as the water will have a problem traveling through the sponge reducing the water turn over), juwel have also now put a green nitrate sponge in their filters aswell which works quite well and this needs changing every 6 weeks, the black carbon will need change every 4 weeks (if u use it), and the white poly pad every week.
there shouldn't be a problem using those two filters together at all in fact u cant really over filter ur tank really (unless u go to great lengths!)
i hope this helps