UP OR DOWN?????

[calicichlid]

Ok heres one for thought....is it better to filter up or filter down or does it make a difference?

Let me start by saying I'm on a new project. I have a 250g water tote that im converting into a long term holding tank. I have been researching out pond filtration and have found that I am still better off with a wet dry system. I have assembled 3 wet/dry system (w/ the help of pretty much everyone here) and I am very please with the results from each one.

With this particular project Im thinking of using a 55g barrel as my filter body. Like I said earlier I have been researching for about a 2 weeks now and want to incorporate several wet/dry and barrel ideas into one system.

I came a cross two filtration system that actually filter the water upward. At first I sorta doubted thier affectiveness, but after thinking it over it for a day, it made since. My thought is that the waste and debri normally settles at the bottom and as the water rises thru the filter media it continues to get cleaner.

Ok with that said I thought whats the difference? "Gravity" in most cases the waste and debri again settles at the bottom and normally will not move unless there is current to draw it in. I cant say that I have not noticed debri in my sumps mostly because I stretched the time period between changing the fiter pad, and the water still remains very clear.

So I was wondering what opinion everyone (who is DIY motivated) may have on the subject and any helpful thoughts.

 

[spiff]

I'd say it depends on the setup and media. Filtering down usually means gravity based. So as long as you have an area for water to back up in to accomodate the extra resistance of the filter getting dirty over time, should be good.

IMO- filtering from bottom is harder and less effiencient as it usually takes pumping action to make happen as well as tight clearances to make sure water is going through media and not around it.

I have seen plenty of sumps that use a combination of both.

 

[calicichlid]

True that, Spiff. Im not a big fan on using a pump before filtration, and it may be possible to avoid that depending on the location of my inlet and outlet placements. one of the filters that like to incorporate is :http://www.koiclay.com/diy/pg5.htm --reference to the 55g barrel setup. I figured if my outlet from the tank is mid level the force of water maybe enough pressure to raise the water back to the inlet tube (very doubtful).

 

[cvermeulen]

Bead filters filter upwards by design, but that's not to improve filtration, it's to allow the waste to drop out the cleaning port when you backflush the filter. Filtering down is easiest to DIY. Filtering up _usually_ means you need to have a pump before the media, which means either you need a pump that can cope with contamination, or you need to prefilter (filter down then up).

Oh and filtering down allows you to use a drip plate, aerating your media, and promoting better BB activity (for what it's worth)

 

[calicichlid]

Yeah, but if i decide to filter down Im not sure that i will be using the 55 plastic barrel.

 

[cvermeulen]

Yeah, but if i decide to filter down Im not sure that i will be using the 55 plastic barrel.

That 55g barrel is designed so that you can backflush it. Opening the drain at the bottom allows all the sediment to flush out of the system. It's not really a filter so much as it is a settlement chamber with a bunch of bio media in it. If you're just doing bio and not mechanical, the main pro/con trade off with the filtration direction is that filtering downward makes it difficult if not impossible to backflush, but it allows you to use a drip plate and aerate your media. If it were me, I'd take filtering up so that you can backflush, and put the pump after the settlement drum, returning to the tank through a spraybar.

 

[calicichlid]

headed in that direction

 

[Dr Joe]

Up-flow filters (except ones incorporating settlement tanks or areas & backwashing features) tend to backflow during power failures and cleaning sending detritus into the pond/tank. They also don't allow for finer filtration materials.

Otherwise it seems to go to personal preference and physical layout.

Dr Joe

.

 

[calicichlid]

Very well understood DR Joe. I decided just to reverse everything and go with the downward filter. Besides I not very fond of putting my pump at the beging of the filtration system.

Thanks every1