New Tank Setup Diagram

Any reason the whole floor space isn't covered by the UGF plates? You don't really want any dead spots...

The LSF gave it as at that point of time didn't had any idea about the filters :(

Its covering 40 % of the gravel bed :(

I bought a new one recently which could cover 90% though. Should i replace the existing one?
 
It would be best.....even better if you made it RUGF.....
 
How large of a tank are we talking about here?

As Rb said a RUGF is superior to a normal UGF. Just buy a powerhead that has a reverse function and get a prefilter sponge.

It's a 15g tank.

I already have a sponge filter
 
Far too small for three goldfish IMHO. And a sponge filter really wont get the mech filtration that you would want with goldies as they are relatively large waste producers. I would go with a HOB in conjunction with the RUGF, but again you will really need a larger tank.
 
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