how many people pump and how many over flow

[ocean rock]

if you take the time to read this thread could you please leave a comment
question is iam trying to find out how many people have used a pump to put water on to there screen and how many use the overflow direct on to the screen ?,
cheer oc

[kcress]

I pump.

[Amphiprion]

Same. I don't have anywhere close to the required volume needed for a sizable scrubber draining through my overflow.

[SantaMonica]

I'd say 50/50

[ocean rock]

hi sm do u then use the overflow and a pump to boost the water on the screen ?

[SantaMonica]

I use just a pump. But it does not matter, as long as the flow is like a waterfall. My screen is wide and takes much more flow than my overflow delivers.

[Outshined]

I use just a pump. But it does not matter, as long as the flow is like a waterfall. My screen is wide and takes much more flow than my overflow delivers.

Hi SM,

I am new to the site and have been reading up scrubbers. I am considering one for the tank I am about to begin (my third tank).

What is the logic behind pumping more than your overflow? If you are doing this, you are simply passing the same water over the screen muliple times. In essence, you are filtering filtered water.

Part of your argument (in other posts, feel free to correct me) for wide vs long screens is that the bottom of the screen does not get nutrient rich water compared to the top. In essence, the bottom is getting filtered water. But, if your screen becomes so wide that you must pump at a significantly higher flow than your overflow, you are getting multiple passes of the same water which, in effect, is the same thing: passing filtered water over the screen.

To me, this suggests the ideal screen width is your overflow flow rate divided by 35 GPH/inch. i.e. a 500 gph overflow would feed a 14 inch screen. Anything wider requires more flow and is filtering filtered water.

This is actually a very interesting observation to me. This means if you are going to pump, your scrubber pump should match your return pump. By setting up your system this way, your scrubber pump becomes a potential replacement for your return pump were your return pump to die.

[SantaMonica]

Each pass of water over the screen only filters a tiny percentage of the water. So the tank volume must be turned over many thousands of times, across the screen. A wider screen allows the tank to be turned over two or three times faster, thus bringing down nutrients two or three times faster.