# DIY Filter....too simple to work?



## bichirboy (Dec 28, 2005)

bichirboy - Member
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I drew up a VERY primative idea for a in-line filter. Tell me if the idea is too simple to work. Just seems like being this simple, someone has thought it before, just never seen it posted anywhere else.

Anyways, I would take a length of PVC pipe and attach screw ends to both ends of the pipe. Then bulkheads would be attached to the screwends and tubing attached to those. The filter media would be placed inside and the water would be flowed by an external pump. Seems simple enough. I am sure there are some refinements that can be made but the basic idea is simple. What do you think? Also, any ideas on pump placement? Any other ideas?










First would be coarse, then medium, then biological and finally filter floss. Pump I was thinking maybe using the Ehiem 1250 rated at 317 gph.


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## QuantumCranker (Oct 9, 2005)

How will you seperate the media? What diameter pipe?


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## niko (Jan 28, 2004)

This design is simple and will work if you have very clean water to start with. The problem is that the surface area of the coarse and fine mechanical filtration is too small. It's enough for the surface of the 2 medias to get covered with fine debries and the water flow will be blocked. The greater that surface area is the better. There are filters that are made in a special way which do not plug up only superficially, but they trap debries in the whole "body" of the media before blocking the flow. Yes, they are more expensive and I've seen then only for micron-level filtration.

I estimate that even with a pretty clean tank the 2 medias will plug up in 2-4 days. At that point the water will either find a way to channel around the media, or the flow will simply stop.

So besides super clean water to start with you will most likely find that you have to clean this filter every 2-3 days.

--Nikolay


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## hoppycalif (Apr 7, 2005)

The idea should work. But, replacing the media would be a real pain. And, the flow would tend to create low resistance channels around the media, instead of thru it. It would filter the water though. I would put the pump after the filter, so it sucks water thru rather than pushing it thru. The little "turbine" pumps we use tend to generate very little outlet pressure, but do suck pretty good.


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## BryceM (Nov 6, 2005)

That's all you need. Simple is good! Make sure you leave a way to take it apart to change media. I'd take a careful look at each end. You should probably use a reducer that transitions gradually from 1/2" to 6" or whatever diameters you end up going with. If you can figure out a way to do it, a bigger diameter would be better than going longer. A long, thin filter would gunk up faster.


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## bichirboy (Dec 28, 2005)

Yeah, the plan was to use large diameter pvc with screw out ends. Media will be seperated by some sort of rings inserted inbetween which would also help in preventing water from flowing around the media. I'll keep researching some and see what I can come up with.


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## QuantumCranker (Oct 9, 2005)

It should work, but, like Hoppy touched on, If the water can find a way around the media, it will use it.(path of least resistance) With a straight-through design like yours, you will have to be very careful not to make it easy for the water. Thats why canister filters usually use a in-through-and back flow. The water has no choice but to pass through the media at some point. The problem would likely be the water slipping down the sides of the pipe, outside the media. I'm interested though, keep us posted and by all means, try it out! Don't abandon it!


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## BryceM (Nov 6, 2005)

If high flow isn't an issue, just really pack in the filter media. The water will have no choice but to find a way through. Flow won't be as much, but your % of junk removed per pass through the filter will be high.


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## stcyrwm (Apr 20, 2005)

I've wondered about something like this myself but never tried it. Another option I have seen is to use an inexpensive water sediment filter as the media container. This way plumbing is all preset for you. I decided against these because the cost of a HOT Magnum at Big Al's is so cheap and I couldn't really beat it doing it myself. In terms of pump placement I would lean toward a submersible to keep noise factor down.

Bill


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## bichirboy (Dec 28, 2005)

Yeah, I will eventially give it a go. It should be realtively cheap to build, the pump being the most expensive part, but still only around $50. If it doesn't work, I can use the pump for water changes or something.


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## bichirboy (Dec 28, 2005)

guaiac_boy said:


> If high flow isn't an issue, just really pack in the filter media. The water will have no choice but to find a way through. Flow won't be as much, but your % of junk removed per pass through the filter will be high.


I was thinking the same. It is going to be a heavily planted tank, so I am only looking for a 2-3 x turnover rate and it will be on a 75 gallon tank, so 150-225 gph should be easily accomplished. That will be another thing too, being that it will be heavily planted, there won't be THAT much waste to be filtered out since the plants will make use of much of the fish waste and such.


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