Overflow-fed skimmer (Semi-mod) Venturi to Airstone counter-current

[MadTownMax]

I posted this in the DIY forum also, but wanted to share with you locals in case you were interested -

Someone has to of done this before, but just in case, here's what I did - very simple.

Advantages - less heat (removing 55w pump), more gentle skimming (airstone vs turbo-blade redsea pump)

Disadvantages - water level control - I assume as algae grows in the two overflow standpipes I will need to "tweak" the level going through the skimmer. The nice thing about this is that I can set a very slow skimmer feed-rate using the standpipe level and then adjust using the skimmer's outlet pipe ....

The motivation

I was not using the return line in my stock AGA overflow, and wondered if I could get better skimming by feeding my skimmer directly from the overflow.

I removed the red-sea turbo-pump from my Excalibur skimmer, and ran hose from the second overflow line (originally a "return" line) directly to the skimmer.

I used a durso pipe on both of my overflow drains ( I wanted to leave the skimmer standpipe open, but this caused the classic "flushing" noise, and also more variation in water going through the pipe), then adjusted the larger of the durso's (1 1/4") until I had moderate flow going through the skimmer - meaning that the water does not cause any turbulence (or bubble like a water foutain) on the exit port of my skimmer.

I drilled the top of the skimmer cup and inserted 1/4" rigid airline tubing and used a 3" limewood airstone driven by a tetratec deepwater pump.

I'm now getting skimmate out of this airstone counter-current skimmer that is similar to that of the venturi-driven skimmer.

I'll get some pictures of the airston-driven mod - there are some in my gallery, but nothing showing skimmate on the new system.

Please share any comments/concerns.

Here's a picture - note that I have now cut-off the inlet pipe in order to eliminate one 90-degree elbow and the small inlet hole, and the outlet pipe also has a 90-degree elbow removed and is now simply a verticle pipe w/ a sponge - similar to a euro-reef skimmer

 

[kaptken]

Nice Practical engineering Nick. Recapture some of the energy of the sump pump via gravity return and eliminate the skimmer pump. thats efficiency.!! and it unclutters the sump too and saves electricity. I need to redrill a couple plexi tanks for larger bulkheads and then cascade the tanks to run off of one pump.

 

[MadTownMax]

overflow-driven airstone counter-current skimmer collection cup


that's a mouthful

 

[MadTownMax]

<a href=showthread.php?s=&postid=7423345#post7423345 target=_blank>Originally posted</a> by kaptken
Nice Practical engineering Nick. Recapture some of the energy of the sump pump via gravity return and eliminate the skimmer pump. thats efficiency.!!

Thanks Ken - I'm hoping to put in either a cheato refugium w/ a surge, or ATS to slowly fill off of the return line for a little extra flow with no extra pumps - but I'm stumped on ways to support it on the frame of my tank (6-gallon tank 12" square - probably about 1/2-3/4 full max puts me at around 24-32 lbs - and I need to support it on my frame - 18" across - think a simple brace made of a few thouroughly coated wood strips would do )

I need to redrill a couple plexi tanks for larger bulkheads and then cascade the tanks to run off of one pump.

Or two pumps - just in case one fails -

In that case I have a pseudo closed-loop in the tank for circulation (a pump connected to loc-line) :lol:

I think I'm a flow fanatic :hmm2:

 

[kaptken]

Just think like the Imortal, Sir John L. Crapper!!

mount it to the wall with some 90 degree braces above the tank. fit it out with a nice tank flapper valve and float trip, with a back up high water open overflow, back to the tank.

then just sit back and pull the chain... automatically of course, so to speak.

 

[MadTownMax]

:lol: I'll have to give it a try.

To save room I was thinking about a U-tube with a siphon break hole at the bottom to prevent too many bubbles - seems like the latest trend - although a flapper valve somewhere in there would reduce bubble worries - I'd rather keep the number of moving parts to 0 - we'll see what happens once I find out if the new place can hold the tank at all

 

[kaptken]

I always use a "T" for a bulkhead overflow. It lets it breath and breaks the vacuum. the water flows better. but i thought you said you wanted a surge tank. that means intermitant flow. thats why you use a head tank with a float trip for the flapper valve to dump the load. WOOSH!!! a little surge action. you just have to scale and calibrate your WOOSH volume to no more than the tank and overflow can handle without , well, overflowing. you get a little , like a half inch of tank level to work with for the surge capacity. so figure the volume you have to work with and calibrate.

 

[MadTownMax]

<a href=showthread.php?s=&postid=7433892#post7433892 target=_blank>Originally posted</a> by kaptken
but i thought you said you wanted a surge tank. that means intermitant flow. thats why you use a head tank with a float trip for the flapper valve to dump the load.

If I do go with a surge, I'm going to use a carlson surge device - here's some details: http://www.masla.com/reef/csm.html
http://www.planet-reef.com/surge1.htm
http://www.breedersregistry.org/Reprints/MFM/v11_aug96/simple_surge.htm
http://reef.bobscomputers.com/surge.shtml
and in spanish: [url]http://www.reefcorner.org/diy/circulacao/surgedevice.htm[/url]

I was thinking of trying this with a small 32-oz bottle first - for the size of my tank, a very small surge may be adequate.

On the other hand - I lowered my canopy another 2" (for brighter light) and it appears that now I'll have enough room to put this surge tank on top of my canopy :rollface: that would really create a strong surge compared to a few inches above the surface that I was thinking about - and reinforcing my canopy to put this 12" cube tank on top is just a few screws away ....