Instead of filter pads you can use filter floss or Poly-fil brand traditional batting which is found at Michael's or fabric stores. This should allow you to get full coverage in the tray to prevent fouling the bio-balls.
It will require more frequent media changing though as it can get dirty fairly quickly. The Poly-fil may be rinsed out a number of times or you can move it around in the tray somewhat to extend its use.
You also might want to buy some egg crate (drop ceiling light grid) and cut it to fit so it rests on top of the bio balls and then you can add some additional batting or floss on top of that to catch more dirt.
However, before you add any media, I highly recommend you remove the bio-balls, rinse them off in tank water then keep them submerged in a bucket of tank water while you clean all the gunk out of the wet/dry filter. I also suggest siphoning out the mulm and dirt in your overflow compartment. This may require a bit of DIY using a length of vinyl hose and a piece of PVC pipe that fits the hose so you can reach the overflow compartment easily.
What is the aquarium size you have with the Eshopps WD-200? Also, which species of fish and how many are you keeping in this aquarium? The reason I ask is that it is possible the W/D filter is a bit too small for your system if you are keeping fish that generate a lot of waste.
BTW, thanks for posting the pic with the W/D lid lifted up!
It will require more frequent media changing though as it can get dirty fairly quickly. The Poly-fil may be rinsed out a number of times or you can move it around in the tray somewhat to extend its use.
You also might want to buy some egg crate (drop ceiling light grid) and cut it to fit so it rests on top of the bio balls and then you can add some additional batting or floss on top of that to catch more dirt.
However, before you add any media, I highly recommend you remove the bio-balls, rinse them off in tank water then keep them submerged in a bucket of tank water while you clean all the gunk out of the wet/dry filter. I also suggest siphoning out the mulm and dirt in your overflow compartment. This may require a bit of DIY using a length of vinyl hose and a piece of PVC pipe that fits the hose so you can reach the overflow compartment easily.
What is the aquarium size you have with the Eshopps WD-200? Also, which species of fish and how many are you keeping in this aquarium? The reason I ask is that it is possible the W/D filter is a bit too small for your system if you are keeping fish that generate a lot of waste.
BTW, thanks for posting the pic with the W/D lid lifted up!