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Improved HOB intake

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3.4K views 10 replies 7 participants last post by  PICKLES  
P
#1 ·
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.

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I 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:




 
Discussion starter · #3 ·
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.
 
Discussion starter · #8 · (Edited)
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.
 
Discussion starter · #11 ·
@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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