The other week I noticed that my Fluval 3+ internal filter wasn't working as good as it used to so I decided to cut my losses and upgrade to a 305 external. This now means I have two 305's running on my 40 UK gal tank.

Is this a good or bad thing?

Personally I've never seen my tank water so crystal clear and I’ve always believed that the more filtration you have the better, the 10x was a recommended minimum right?

So with these 2 filters running side by side does anyone know the filtration rate this gives the tank?

This is an excellent thing because the 3 Plus pumps 140 gph and the 305 pumps 260gph giving you a grand total of 400gph. So it's perfect

Thank you JWen.

Did you say you have two 305's running or just the 305 and the 3+?

I've got 2 305's running on the same tank.

Edit: the 3+ internal died on me.

*steals your filters* MINE

Okay not really, but yeah, you've got enough filtration. I was told that as long as you've got a calm spot for them to rest in, it should be fine to go above the 10x minimum.

You've got it pumping at 520gph in a 48 gallon tank, so you're covered but not going to have so much power that you're going to tumble the fish, you know?

L. E. Pirin: No i wouldn't part with my filters! LOL
And as for calm spots there are loads.

I also love you Hammond sig SG1 RULES!!!