hey all, I just bought this, and Im not overly sure how it should be set up. Can anyone help me with it?

Dymax 107 Diffuser

Should it be filled with water? This seems unlikely as the only way I can think of to fill it is to blow water in it with a bit of tubing. If not, how (as it states) is the spiral supposed to keep the gas in contact with the water longer? Also, there appears to be a small hole in the base of the spiral, which, when filled, the gas just comes out of. Any ideas? Im mildly confused.

Thanks

I've not seen one of these yet, but it looks interesting. If you submerge it, does it fill with water through the diffuser plate?

Here's my guess as to how it operates based on look at the photo...

Once the container is full, the bubbles will "pull" water into the spiral as they pass through. It looks like the gas tube ID narrows near that opening at the bottom of the spiral. As the bubbles escape from that narrowing they will accelerate into the spiral going past the opening in the side of the spiral. This will create a lower pressure inside the spiral sucking water into it through that opening. You will then likely get a series of bubble-water-bubble-water-etc... going up the spiral.

This is similar to the concept that Python siphons use. Only in that case it uses water from the faucet as the motive phase rather than CO2 bubbles

It's an interesting concept because the CO2 should dissolve some in the spiral and any that doesn't dissolve should be turned into microbubbles as it passes through the diffuser plate. It also should work as a self contained bubble counter.

The big question is will it fill with water when submerged or if not, how do you get the water in.

Pls let me know how it works once you've got it up and running. I've been meanig to upgrade my diffuser as well and that looks like a cool device...

Nope, stays empty if submerged, which is weird if you ask me lol. the only way i could fill it was to use a bit of tubing to blow water in the bottom. Once full, the Co2 bypasses the spiral completely by escaping from the hole, this is why Im thinking Ive gotton it wrong.

*ponders*

A couple of things...

First, treat it like a diffuser stone and soak it for a while before using it.

Second, I can't believe the coils are to improve contact with the water - it's for aesthetics and to act as a bubble counter. Over time water should start to make its way past the disk into the diffuser. The hole at the base of the spiral will allow water in with the bubbles so you can see them travel up the spiral.

Thanks for your reply Turbomkt, its full already, as I filled it by blowing water into it, but the bubbles dont travel up the spiral at all, they just exit from the hole in the bottom.

This looks like a scam to me. The diffuser disc will probably pass mostly, if not only gas - not water. So, getting CO2 enriched water inside the device doesn't accomplish anything I can see. It looks like it would just be an ordinary disc diffuser with a nice looking coil of tubing inside to make it look more "high tech". Why not email the company that makes it and ask how it is supposed to function?

Thx Hoppy, I was actually thinking the same thing. Ive just emailed them just before I read your post. Just didnt make sense to me. They replied and said just attach the tubing as normal, it will fill up on its own. Ive emailed back asking about the spiral and how its supposed to do what they claim it is on their website.

It was quite expensive in comparison to the ones with no spiral, so Im keen to get to the bottom of it.

Is the spiral full of liquid or air when the bubbles by-pass it and go out the side hole? If the spiral is still full of air the air can act as a plug. I wonder if the air in the spiral will dissolve into the bulk liquid with time or something. I wonder if the bubbles will still bypass the spiral once its full of liquid.

Anytime a gas is in contact with a liquid that is not saturated with that gas it will dissolve into the liquid. In this case there will not be as much mass transfer between the gas bubbles and liquid phase as you would expect from a ladder set-up because there will not be as much contact area, but there will be some mass transfer. It may not be much though due to the limited gas-liquid contact area so the spiral could act more as a neat bubble counter.

No, the spiral is full of water, as is the whole of the bowl part. I think Hoppy's right, I think its there to make it look pretty and expensive.

On the flip side, it does work ok.. its dropped the pH of my tank faster than the vario that I was using before, and with less gas. Im just curious now as to whether the tube is purely a 'go faster stripe'

Hoppy –

I didn’t see your post (must have been writing mine when your’s was added) and I wish I had. It would have saved me from a bad assumption and mistake… You’re correct, I was assuming that the water in the diffuser was approximately in equilibrium with the water in that tank which is only true if water continuously passes in and out of the diffuser, not a good assumption in this case. I wasn’t looking at the big picture and I know better than to do that…

As you pointed out, if there is no continuous transfer of water in and out of the diffuser the water inside the diffuser will saturate with CO2 at which point no more gas will dissolve into it. End result – the spiral would be an expensive (but neat) bubble counter if it actually worked unless they’ve designed a way for the water to flow in and out of the internals of the diffuser, and it doesn’t look like they have.

I’m not sure why the spiral isn’t working when full of water. Maybe they made the hole in the side too big so the bubbles have an easier time going through the hole rather than traveling up the spiral. Either way, it sounds like it probably doesn’t matter much other than for esthetics.