Venturi setup to change aquarium water....

[Dennis Peacock]

Well, one more plastic gizmo has broken that I use every week to change the water and clean two 55 gallon aquariums. I thought I could build the setup out of brass fittings but for some reason, I'm not getting any vacuum out of the 1/2" brass T setup. I know I can go and buy another Blue Magic Waterbed Drain and Fill but it too is plastic. I want to make one up that I can use for years without it breaking.

Anybody here ever buy a venturi setup to siphon the water from an aquarium? I'm looking for water powered by the kitchen faucet to create the suction.

[Malcolm McLeod]

Anybody here ever buy a venturi setup to siphon the water from an aquarium? ... by the kitchen faucet ...

Dennis, The very first real engineer that I saw at work created a venturi vacuum to collect selvage trimmed from a sewing operation in a Levi Strauss plant. I was hooked.

To get good efficiency would take some calculation, but I suspect that's not hugely important in this case. Anyway, I too would probably look to brass fittings to get what you want.

I'd try to use brass in 1/2 pipe for the low pressure (suction) line, 3/4 for discharge, and 1/4 copper tubing for the high pressure. (Although PVC would probably be fine for the low pressure side.) Like this, maybe...
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I haven't messed with copper tubing and compression fittings in a while, but I believe you can drill a 'passage hole' thru the fitting to allow the tubing to insert into the fitting and past the shoulder. And, using a fitting with a 3/4 MNPT on the companion side, should allow enough room to drill out and pass the 1/4 tubing thru.

Two things will be key: 1) No leaks on the suction side or around the copper; 2) Try to keep the tubing centered and have a smooth curve into the discharge line.

[Malcolm McLeod]

This might be easier to build:
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Edit: To improve efficiency, try to round over the inside edge of the discharge pipe 'inlet' - near the 1/4 tubing (another argument for PVC?).

[Dennis Peacock]

Malcolm,
Here's what I have sitting near me. I took a 1/2" close nipple and epoxied a 1/4" hose barb fitting in the middle of it and trimmed it back some and screwed it all together. The 1/4" barb was on the inlet side just before and screwing into the T. I never got any suction at all on the setup and took it apart to what is now in this pic. I'm just missing something that makes all this work.
I want to attach one end to the kitchen faucet and the opposite end would discharge into the sink drain. The branch would be the suction pulling water from the aquarium (about 30 feet away). I was using a Python No Spill Clean & Fill Gravel Cleaner but the plastic part that connects everything together broke...as the previous plastic one did. Thus is what I'm trying to put one together with brass or pvc or whatever I can get to work. :)

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[Dennis Peacock]

This might be easier to build:
349629
Edit: To improve efficiency, try to round over the inside edge of the discharge pipe 'inlet' - near the 1/4 tubing (another argument for PVC?).

Yes, this is more of the design / function I've been looking and searching for.

[Malcolm McLeod]

The 2nd iteration doesn't require any fancy bending or tightening any threaded joints with a 'hook' protruding - so easier build (..he said?).
Not sure how everything lays out in your existing test rig, but the end of the high-pressure, high velocity line (1/4) MUST extend past the branch inlet.

Hope this helps, and happy 'draining'.....

Just FYI - I was about 13-14 yrs old when I first saw the engineer build this -- and had never even heard of a venturi. When he told me what he was doing - using high pressure to create a vacuum - I thought he was pulling my leg. He used 150psi plant air and it would suck the hair off a dog!

[Phil Mueller]

I know you want to make one, but I use a Python brand syphon/hose for my aquarium. Monthly for about 10 years without a problem. Yes, it's plastic, but obviously very durable.

Off subject a bit, but do you really have the need for weekly water changes? Are you over stocked? Have you actually tested the water at 7, 14, 21, etc., days? For my current 55 gal, reasonably well stocked, I see no appreciable rise in nitrates/nitrites in 30 days...certainly not to a harmful level.
I got hooked into an aquarium forum for awhile, and many advocated weekly...but forum folks can get a bit over the top in my opinion.

Oh my, did I just take a jab at the sharpening threads!?...no harm intented!

[Dennis Peacock]

I know you want to make one, but I use a Python brand syphon/hose for my acquarium. Monthly for about 10 years without a problem. Yes, it's plastic, but obviously very durable.

Off subject a bit, but do you really have the need for weekly water changes? Are you over stocked? Have you actually tested the water at 7, 14, 21, etc., days? For my current 55 gal, reasonably well stocked, I see no appreciable rise in nitrates/nitrites in 30 days...certainly not to a harmful level.
I got hooked into an acquarium forum for awhile, and many advocated weekly...but forum folks can get a bit over the top in my opinion.

Oh my, did I just take a jab at the sharpening threads!?...no harm intented!

LOL, no harm done Phil. :)
No, I don't do weekly, I used to but I don't any more. I've gone through a couple of the Python plastic changers. My gizmo above does everything I need it to do...except...pull enough vacuum to clean my gravel bed in both 55's. None of my tanks are over stocked. I keep them under stocked to make it more manageable for me and still enjoyable for family and friends that really enjoy watching my fish and live plants. I prefer to do water changes about every 2-3 weeks which works well for my plants and my fish.
I'm still fighting an algae problem in my aquarium that is in another area of the house.

[Lee Schierer]

It's not brass, buut here is one your can make yourself that is all but bullet proof. Simple T Venturi. (https://www.youtube.com/watch?v=j47XbRzCcNo)

[Myk Rian]

Would not a drill powered pump be easier and less involved?

[Dennis Peacock]

Would not a drill powered pump be easier and less involved?

Myk,
Yes it would but....who would be vacuuming the gravel and keeping the fish out of the way of the vacuum hose? :D :D
It's not only a matter of water exchange, it's a matter of getting the junk out of the gravel base along with the waist water in the tank.

[Dennis Peacock]

It's not brass, buut here is one your can make yourself that is all but bullet proof. Simple T Venturi. (https://www.youtube.com/watch?v=j47XbRzCcNo)

Lee,
That's an air venturi to aerate the water. Maybe it's the same principle. I'm just missing something along the way that aids in speeding up the water enough to pull a good suction.

[Jerry Bruette]

Dennis
We use vacuum generators at work for picking up parts, Vaccon brand, don't know why they wouldn't work with water.

In the Navy we called them eductors, I've also heard them called steam ejectors when steam is used to create the vacuum.

The one on the ship I had to repair would pump 250 gallons a minute, a little big for your aquariums.

[Lee Schierer]

If you make the small tube slightly larger and force water through the small tube you will create a low pressure in the side of the tee. Run a large tube up to the small tube and reduce the size right at the small tube you want a high velocity flow through the small tube. 349740