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rotten · Joined: 26 Feb 2005 Posts: 37 Location: x0||||||

Now that everyone has their aquarium pump, it's time to move onto something a bit more difficult (and expensive). This will probably add around $100 to your pump. But i think it's worth the added expense.

After a while, my tetra pump seemed to gain more vacuum then i prefer, so i needed a way to regulate it.

Now this part is a bit dangerous, and if you have no electrical skills do not attempt this. Be careful with this around water. Make sure you use a water trap and do not even think about using this without a ground fault plug in. In fact, forget that, don't use for wet pumping. I'm serious, don't even try this. I am in no way responsible for any accuracy, or your safety, i'm just showing you what i did, and what worked for me.

Now that were past that...

Step one, purchase an adjustable vacuum switch. I got mine from McMaster Carr. http://www.mcmaster.com/ Not the cheapest prices in the world, but they deal with the public, rather then wholesale, and no minimum requirements. The switch i bought was part number 46995K34.
Just put that in their search box. It costs around $90 + shipping (around $6.00 to my house) It should arrive about 2 days later. They are seriously fast.

The things to look for in a switch.

Adjustable vacuum rate that goes down pretty low(make sure you get a vacuum switch and not a pressure switch)

Enough amperage handling for the air pump (shouldn't be too much of a draw)

Set up for normally closed operation (or for setup for both normally closed or normally open)

Waterproof would be nice

This switch 46995K34 although more expensive, exceeded all my requirements. It is adjustable from -1" HG to 30" Hg. (plenty of adjustment ) It's rated @ 5 amps @ 125volts, which is plenty. It can be set up for either normally open or closed. This model has the nema 4 enclosure making it pretty waterproof. The model next to it is about $20 less but had open terminals on top making it more dangerous and it is not nearly as waterproof. I'll take the added safety for only $20 more.

Now the setup.

(pictures to follow)

rotten · Joined: 26 Feb 2005 Posts: 37 Location: x0||||||

Here are the steps

rotten · Joined: 26 Feb 2005 Posts: 37 Location: x0||||||

The last picture was supposed to show where to hook you gauge.

rotten · Joined: 26 Feb 2005 Posts: 37 Location: x0||||||

So for operation, everything works perfect.

The pump, pumps to where i set it (aprox. 4.5" HG). Then turns off. When the pump loses around 1" HG it turns back on and pumps to 4.5 and shuts off again.

If you have any questions, or find a cheaper suitable vacuum switch drop a line here.

rotten · Joined: 26 Feb 2005 Posts: 37 Location: x0||||||

471 views, i guess no one is either interested or understands, oh well.

RicanMan2001 · Posted: Wed Jan 02, 2008 3:48 am Post subject: Exciting Pictures

Dear Rotten,

Thanks for posting this. Probably you did not have replies before because usually people are looking for cocks and balls pictures. If you connect you cylinder to your machine and show how works your invention you may get a lot of attention. Thanks.

rotten · Joined: 26 Feb 2005 Posts: 37 Location: x0||||||

Well if that is the case perhaps we need an equipment section. I know a lot of people are interested in building their own lower cost equipment. We have even had popular posts showing how to build equipment. I guess i just need a dick picture to get it going.

wwbigballs · Joined: 23 Dec 2007 Posts: 30

went2sleep · Joined: 01 Jul 2002 Posts: 292 Location: Owensboro,Kentucky

Hey fantastic post! I have no idea why you haven't been praised 1000 times over! This would save people over 250.00-300.00 bucks for a silent automatic pump! Sounds and looks very simple for those of us that have ever used a soldering iron and have the slightest electrical knowledge. Thank you very much for taking the time to document the process and sharing your ideas. I am buying the parts and building mine ASAP!

mch · Joined: 08 Feb 2006 Posts: 84

pumpmeister · Joined: 29 Jan 2007 Posts: 15

I have an aquarium pump and I just made a simple electric outlet with a dimmer switch inline. To adjust the vacuum just turn down the dimmer switch. I works great and very cheap.

PumpMonkey · Posted: Sat Jan 19, 2008 9:35 pm Post subject:

Great idea rotten ... but I must admit $100 dollars is hard to justify when one is using a pump that is only $18 - 30. It does however, have the advantage in that the vacuum will fluctuate.

The dimmer switch idea was an idea that I also used ... worked great for me.

rotten · Joined: 26 Feb 2005 Posts: 37 Location: x0||||||

PumpMonkey · Posted: Tue Jan 22, 2008 2:24 am Post subject:

Tried it for a short time ... so cannot really say.

However, the new dimmers do not get hot like the old ones did.

lohkuf · Joined: 05 Jun 2007 Posts: 2

Just wanted to post a similar idea that's a lot cheaper. I noticed that the screw control on the pump works to set air flow, but has no control on the max pressure.

I've come up with this idea and I've set this up with my converted aquarium pump and it seems to work really well.

I bought a 3 way "gang" valve (love the name) from petsmart along with the pump. After converting my Rena 300 pump, I hook it up to the inlet. I then hook up the tubing that runs to my cylinder to the first outlet. In the middle outlet I've fitted a gauge from an old hand pump (used a small length of tube, some electrical tape, and a hose clamp to secure it). The 3rd outlet I leave open.

By the way, my guage is screwed up and 5" is actually 0". So the guage is reading about 3" in the pic.

After setting this up, I set the outlets for the cylinder tube and gauge to "on" (12 o'clock) and the open outlet to "off" (9 o'clock). Placing my finger over the open cylinder tube, I can get a reading of the max pressure (about 7" in my case).

While keeping my finger on the tube for the cylinder, I adjust the open valve to let a little air leak into the system. I keep adjusting this until I get the desired pressure reading on the gauge. It can be a little tricky but not too hard to do.

I then put on the cylinder and hook up the line and find that the pump achieves the same pressure and doesn't go any more because of the air leak. I can then make fine adjustments to the open valve if I want from 0” to the max of 7”.

This pulls a very steady pressure, no ups and downs, and achieves the pressure after a minute or so (for my big sun tea jar). I can break the seal on the jar with my finger for a quick break, and when I seal it back up it goes straight back to the same pressure.

One more advantage is that even if there are small air leaks it doesn't make a big difference, the pump just keeps pumping and lost air. This can be the advantage if for some reason you're not making a good seal with your tube. If it's not a big leak you'll continue to maintain pressure.

Check out my pic if you have any questions as to how I did this.

-j