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PICKLES 01-08-2013 05:52 AM

Improved HOB intake
One thing I've never liked about HOB filters is that the intake is just under the outflow and it seems like water is just circulating in a small space. I decided to remedy that by moving the water intake way to the other side of the tank. I just cut up some 1 inch PVC pipes and used 3 elbows.[ also filled up the inside of the PVC pipes with some K1 media so that it would increase the filtration capacity. The HOB intake goes into the taller pipe. The taller pipe has to be higher than the level of the water so the water intake can only come from the other end. The other end can be any height as long as it's under the level of the water as well.

I just realized that if I made the other end higher, it will limit leakage from the tank if the HOB springs a leak.

The blue things seen at the ends are 1 inch bioballs that act as gates or grates that prevent the K1 from leaking out. The one at the far end also prevents fish from getting sucked in. I may put a big sponge over that as well for mechanical filtration.

This is such a simple device that I don't know if anyone has ever made anything like this before. If not, may I present the JohnHuff intake:

The Dude 01-08-2013 06:09 AM

Any pics setup in the tank?

PICKLES 01-08-2013 06:32 AM

I will take some over the next few days and post them. The tank (55g) is really messy right now because I have 4 other filters in it and some loose K1. The excess K1 came from a leaking DIY moving bed filter which I have now removed.

jlieu 01-08-2013 06:35 AM

This is pretty fly. Interested in a pic as well to see it in action!

aznartist34 01-08-2013 08:14 AM

I think it would work better if you change the setup to act as an undergravel filter.

jhays79 01-08-2013 09:53 AM

That's pretty sweet!

JustAGuy716 01-08-2013 07:19 PM

I did something similar the other day based on This thread at fishforums

The only change I made was adding a sponge pre-filter on the pvc intake to help eliminate any pipe cleaning concerns - works great on a 20-gal extra high that I got off craigslist.

I like the bio-ball idea in the end of the pipe here, though, and might add that under the sponge just to keep stray "stuff" out of the tube when cleaning the sponge.

PICKLES 01-08-2013 07:51 PM

Yours looks good! One difference is that my HOB intake is not sealed to the PVC pipe, it just sits in there. I'd thought about using larger diameter pipes to allow for a better flow/less restriction but even the next larger diameter pipe looks out of place. Atmospheric pressure will keep the water level inside the pipe at the same height as the tank as long as the pipe is not blocked. If the inlet gets blocked the water level inside the pipe will decrease until the HOB intake sucks air. Then the pipe will need to get cleaned, but it's relatively easy to remove as it's not sealed to anything.

I've already noticed some small detritus being drawn in at the "in" end. I'll see if I can find a fairly coarse sponge to put over it as I've found that sponges can quickly decrease water flow. And both ends can be detached at the bio-balls so I can clean the pipe by popping the "out" end off and putting the vacuum over in the "in" end to drain it backwards.

Diana 01-09-2013 02:44 AM

I do something like that.

Going backward to the direction of water flow:

Down from filter to a PVC Tee.
Tee has short pieces of pipe and then more Tees. Each of these are aimed up, and have a short piece of sponge over it. The last in the line is a 90* elbow.
Longer tanks get as many as 4-6 inlets. Smaller tanks usually get 2-4 inlets.

The intake is as centered as possible in the tank, on the back wall. Pipe is sized to fit the filter intake, but after that first Tee can be reduced.

I do not use any glue inside the tank. If it leaks, where is the water going to go? Into the tank! ... is that a problem? Leaves the whole assembly more adaptable.

I keep all the inlets quite low. A lot more dirt on the bottom of the tank, and I do not need the 'skimmer' effect of high intakes. Still, it does need to be above the substrate. The substrate can get into the sponges, especially if there are fish that dig.

This works really well for river tank set ups. The outlet (Filter or power head) would be at one end of the tank and the inlet at the other, per the article at Life in the Fast Lane.

The Dude 01-09-2013 03:39 AM

So does this thing completely replace the intake tubing that fits over the impeller? How did you get it to fit into the space perfectly? I'm assuming the part with the blue around the seals goes around the impeller

PICKLES 01-09-2013 11:15 AM

@The Dude: The intake tubing sits inside the tall pipe loosely. It doesn't need to be sealed to it as the water level inside the pipe is the same as the tank due to atmospheric pressure. However, the top of the tall pipe must be higher than the tank water level. The blue parts are the bio-balls.

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