tom, the sweetwater stones you have been using,are they suppose to have very fine bubbles like those coming from a eheim or the zoo-med diffusers?i've tried these using 20lbs of co2 and can only get a few larger bubbles at stem end.also connected to air pump and bubbles are about the same as most stones,large. am i doing something wrong? i'm soaking some right now in water to see if that will help.regards,cornhusker

Did you get the fine pore Sw stones?

See:

http://www.aquaticeco.com/index.cfm/.../9751/cid/2328

The smallest one is what you want.

Regards,
Tom Barr

I ordered 4 of the stones, from the page you recommended before, and mine too are a disappointment. I get large bubbles - maybe .25 mm in diameter, which largely rise and dissipate at the water surface. This post is the first I have seen about "fine pore" stones. I think you goofed before!! The discussion in their website catalog about the regular stones leads you to believe that those produce the finest bubbles that can be done, so I didn't try to find anything in their catalog mentioning still finer bubbles. Drat!

Should be these:

Those are them.
the largest bubbles I have coming out of two of these is about the size if a 12 font peroid " . "
They float around and get pushed all over.

I have 6 Azoo diffusers, some produce smaller bubbles, some produce larger bubbles even!

I have 3 other diffuser brands also, same thing, the ADa diffusers also have some rather larger bubbles, the Red Sea diffuser 200 => junk.

Several LFS's here in SF Bay have these(not the SW stones) and use them, so we have their feed back as well.

Other folks have used the limewood stones they use for skimmers.

Hopefully in the next year or so, someone will come up with a nice super fine mist making method that's cheap and consistent.

Regards,
Tom Barr

Those look just like the ones I got, and they definitely are not the "fine pore" stones. Maybe I should offer the remaining three for sale as "sweetwater stones", and hope no one else knows there are two kinds. (heh, heh)

I contacted aquatic eco-systems and they have a small order charge of $5.oo,plus over $10..00 shipping for six stones.i happen to be ordering from F&S and saw in their catalog what looked like the same as sweetwater stones.so i asked what vender they received these stones.they indicated from aquatic eco-systems.so i presumed they were the same thing.price,$1.69 each.now it could be that more than one kind is made,but these sure look like the ones on the AES website.who knows! regards,cornhusker

A couple weeks back I thought I'd give the mist method a shot and ordered several Sweetwater stones from AES. I only tried one of them, but it certainly didn't produce a mist of tiny bubbles the size of a period. Most were rather large (though probably smaller than a regular airstone), and floated rapidly to the surface even when placed in front of a vertical spraybar. Overall, it sounds pretty much the same as Cornhusker described.

I double checked the order receipt and what I ordered was AS10 = Fine-Pore Diffusers for Ozone and Pure Oxygen, 3/16" OD, ABS, 1.5" x .5". They look just like TW's picture.

The main thing that got me was the increase in CO2 expenditure required to get any sort of "mist" going. Normally I run about a bubble a second through my canister, but with the SW stone I had to crank the flow up until bubbles were just ripping through the counter. I never did let it all stabilize so I really don't know where the flow rate would have ended up when the pH was set. I just packed it in and went back to my original setup.

Is it possible we're doing something wrong? Normally, I've got the pressure regulator set to around 12-15 lb and the needle valve nearly closed in order to achieve 1 bubble/sec. With the SW stone, the regulator was the same but I opened the needle valve quite a lot.

When I had mine going, the regulator was set in the 40psi range. They seemed to do better with the higher pressure. I got the small bubbles except where the stone touched anything, like the side of the tank or the substrate, there it was one big bubble.

BTW, that's not my picture, it's linked to another post here somewhere. But that's what my stones look like too. I've since switched to the Rio bubble-chopper powerhead.

TW

The pic with the rulers is a pic I took of mine when they came in. Still haven't run them.

I just took these pictures of me blowing air through one of them with my weak lungs.

Blowing a little and then a lot.





Is this a fine mist? I suppose it might depend on the pressure you are running. It is finer with less pressure but when you blow through it you can get the bubbles just as big as any airstone. In order to get the small bubbles I had to blow just enough to leak some bubbles out, one or two tiny streamers. Any more pressure than that and it's normal bubbles.

It looks like a normal airstone to me.