# HoB "Surge" Filter



## mozart531 (Sep 25, 2010)

I was trying to think of a way to make an air-powered wet/dry filter for the sake of designing something (mechanical engineering and aquariums are my two loves). This is the design I came up with.









Bubbles (from the purple airstone) and water are trapped in a tube. The air forces the water to travel up the tube and into the reservoir above and behind the tank. When the reservoir fills with enough water to prime the siphon, the siphon will drain all the water out of the reservoir and into the aquarium. 

Filter media can be put in the bottom of the reservoir. When the resevoir drains the media gets air exposure and when it's full it filters water. That's the basic principle of a wet/dry filter, right?

I got the bubble/water tube idea from 



. I just cut out the stream and replaced it with a aquarium and an airstone.

Unfortunately, I don't have the time or money to build this. I'm on a college schedule and budget. I'm just throwing out ideas to see if anyone wants to try it.


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## Mikaila31 (Dec 18, 2008)

You might not want the return tube submered in the water of the main tank. Because even once your filter area is full enough to prime to tube it is going to have to force the now trapped air out of the tube. Like wise if it is not sumbereged it may not fully prime and just trickle down the tube as fast as it is filling up.


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## mozart531 (Sep 25, 2010)

Hmmm... I can't believe I missed the air pocket in the siphon. I'll have to revise the design.


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## mozart531 (Sep 25, 2010)

If I just remove the end of the siphon from the aquarium and use narrow tubing the siphon should be fine. The Cup of Tantalus works by filling it up to the point where the siphon is flooded. I'm sure there is an air bubble in the siphon initially. If the siphon is narrow enough, maybe it'll force the air out with the water coming in.

A glass version of the Cup of Tantalus. I'm not sure if the Greeks actually used glass or not.


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## bearwithfish (Sep 29, 2009)

you are dealing with a much larger issue than a closed glass and we must remember that we are also dealing with 2 containers not one.... how ever i like the principle .. the over all idea is good what must happen now is to look at flaws and find solutions ......
1st. if you have 2 containers containing water and a syphon between the water will attempt to find level pressure between the two. so if the reserve tank is higher it will always emoty it self this brings 2 issues to mind 
a) how to keep the siphon primed
b) how to keep level so that the reserve is never empty
solution - lower the reserve tank so the bottom of the reserve is 2-3 inches below the surface of the maintank water line..
this will solve both issues however we now must consider another important issue
water level
assuming we have a working system we are drawing from the main tank to fill the reserve and then flooding back into the main ....
we need to be sure that through our removal of water from the main tank we are not 
a)breaking the syphon
b) not removing so much water that various pumps and life forms are out of the water
solution
be sure the siphon is low in the tank (potential issue with the surge moving around substrate) 
and be sure all pumps rocks etc are also low in the tank 
this creates a number of other issues such as limiting what cam be done with the tank in general..
the last issue would be the fail safe
in the event of a siphon failure, power outage, or other catastrophe what does the system have to ensure we dont have a flood or other major issue (fire etc.) 
solution- not real sure any one have ideas??? float switch perhaps?

not trying to sound negative but rather i would like to see some of these addressed in the design so that when i or other members attempt it we are thinking about all of the basics and safety issues...oh and be sure i may attempt this one just to find the solutions to the issues .... man i love threads like this LOL


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## mozart531 (Sep 25, 2010)

Here is a revised design. The bottom of the reservoir is bellow the water level of the tank, so the siphon will remain primed. The outlet of the siphon is turned to the side to limit substrate disturbance. It could be pointed at an organism that likes periodic current (maybe some type of coral). In the event of air getting in the siphon, an air outlet is situated to allow air pockets to be forced out by the rising water. A 1-way flow valve, like those used on the airlines from an air pump to the aquarium, prevents air from re-entering the siphon.









Here is a close-up of the air outlet:









This has the advantage of allowing the system to recover from a siphon failure without intervention from the owner. Also, it will self prime. For those more electrically minded, it may be easier to use a float switch to turn off the pump if the reservoir level gets too high.

The volume of the filter is not intended to be too large, maybe 5% of the total system volume at most. This should allow for rockwork and pumps to be near the surface, just not directly at the surface. 

I think this covers all of the mentioned design flaws. Did I miss anything?

P.S. I didn't take any of the criticism as negative, bearwithfish. Constructive criticism is always appreciated.


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## bearwithfish (Sep 29, 2009)

i am glad to hear that.. and i think you have found come very creative ways to solve those issues.. looking at your modified plan i thin kit is very much something that can work.... nicely done!!!!!!!!!


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## zof (Apr 23, 2010)

This is going to be a really interesting build cant wait to see what you come up with.


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## mozart531 (Sep 25, 2010)

Thanks guys. 

Anyone attempting this design should be aware that I have not personally used the water/bubble uplift system. I cannot say it will actually work perfectly, as I've never tried it myself. I've just seen it done in the pulser pump. It will probably not fill the reservoir quickly unless there are multiple uplift tubes or you have a lot of airflow. Also, I _think_ that the uplift tube should be slightly larger in diameter than the airline because it has to accomodate all the air from the airline and the water it is lifting. The uplift system should be made first to make sure it works before spending money on the rest of the filter.


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