[azzah]

mods i accidently posted this thread in the wrong section please move it if needed

I got my tank second hand and the original owner had set it up as follows

Weir:
Packed with black sponges/pads

sump with 2 rotating arms to disperse water:
top layer: whitle filter pad
2nd layer: Black filter pad
3rd layer: couple of hundred bio balls
Bottom layer: More black filter pad

The problem I thought with this was that half the bio balls were under water and from my understanding they need to be out of the water with the water just rinsing through them so I did the following

Weir:
Top layer: white filter pad
2nd layer: 1 black filter pad
3rd Layer: small amount of bio balls
4th layer: 10cm layer of matrix
Bottom layer: 2 black filter pads

Sump:
Top: couple of hundred bio balls
bottom: 2 layers of black filter pad

All bio balls in the sump are now above the water line and water trickles through the media in the weir and sump. I'm sure others have done this or something similar to this but thought I would share this in case others haven't thought of this.

This is what the weir looks like

 

[Mcdaphnia]

Weir? Do you mean the tower? A weir is a type of dam that creates a waterfall effect on the downstream side. I can see how that might be descriptive of the way the tower works. In a partial sense it is a contained waterfall.

Bioballs are more effective in the splash zone than when submerged. However they still bio-filter submerged under the spash zone, just not as much since there could be limited oxygen available. A filter might be set up that way for a good reason, to eliminate microbubbles. Especially in saltwater but also in very hard water, microbubbles can be a problem, accumulating on surfaces in the tank, reducing water clarity, and even entering the fish. The submerged bioballs can capture some of the microbubbles instead of letting them pass up to the tank, but plenty of other media and other methods, such as staggered plates to lengthen the pathway of the water back to the tank also will do this. in fresh water though, it is much less likely to present a problem.

 

[azzah]

Weir? Do you mean the tower? A weir is a type of dam that creates a waterfall effect on the downstream side. I can see how that might be descriptive of the way the tower works. In a partial sense it is a contained waterfall.

yep the tower as you put it is also called a weir. Read the definition of Pre-Filter In this link

 

[Mcdaphnia]

yep the tower as you put it is also called a weir. Read the definition of Pre-Filter In this link

Oops! When reading fails, look at pictures. About halfway down this page from the same pet dealer's website are a couple drawings of Pre-Filters. http://www.tropicalfishstore.com/filtration.htm They are inside the tank and are left empty or with only a foam sock for mechanical filtration, not in the wet/dry which is where I hope you were picturing your media layers.

I still think your name for a tower makes sense in a functional way if you do mean that part of the wet/dry. Even though it is not a term Tennecor or anyone else I have heard use that way, I was almost sure I understood your meaning as the section inside the wet/dry filter designed to hold the bioballs.

However if you are putting that stuff in the pre-filter, I'm not so sure it's a good idea. Not a lot of available volume for the effort involved. It would be difficult to work with while a tank is operating should the pre-filter clog or something, because of the tight access and limited space.