Pond Boss Forums AERATION Systems questions What are best brands/types of diffusers

Where to find specifications and reviews of shallow water 6-7 ft. diffusers. and what are the best brands and is stone or EPDM better. Also where is best place to buy. I am planning to get a GAST 0523 pump.

The manufacturer often will have specifications of their products but remember those values can be biased in their favor. Aquatic Ecosystems (Pentair) in Florida has done some testing with membrane vs stone diffusers. I prefer the membrane because it tends to clog less when used in hard water and membranes are easier to clean. Membrane diffusers are not clog free despite the advertising. Which is the best is like asking which truck is best Ford, Chevy or Dodge. All have advantages and disadvantages. Best place might not be the cheapest when it comes to getting advice about any problems you are having.

I have a different opinion than Cody but it's just that, which I have from my personal experience.


After using air stones and membrane diffusers in both ponds and fish tanks, I'm phasing back to all stones. I've had issues with membranes diffusers I never have with stones. You have to clean both anyway, and the md's aren't user friendly when it comes to disassembly and cleaning both sides of the rubber membrane.

The md's are basically impossible to take apart even though they are threaded. Additionally the original designers should have made the standard md diameter a little smaller, to fit in the bottom of a five gallon bucket for a muriatic acid soak, where a few inches of the acid would suffice.

In my tanks the md's at some point burp large air bubbles and after lots of observation to find the cause, and cleaning the membranes the best I can, they still have issues. My best guess is either the membrane becomes clogged on the inside or air escapes underneath where the assembly screws together.

That said, if I bought another md it would purhase a design produced by Matala, which has a removable stainless shell clamp around the circumference to remove and adequately clean both sides of the rubber membrane. In a nutshell not disposable like the other md's out there. Too expensive to be disposable!

That is what I am using, Matala. Have 8 all together (three doubles and two single 9")

Have nothing to compare them with so don't know if they are good or bad. They seem to work and move water.

So far my cleaning has been with them running on the bottom of the pond and I going down either with scuba or breath hold and scrub the surface with my hand.

Oooooh. Just remembered. Before leaving a month ago I had one of the doubles that nothing was coming out of one of the diffusers. It was flat as if air pressure was not pressing against it. The only thing I could figure is that at some point when I shut the air off, it collapsed and the internal check valve built into the diffuser stuck to the plastic housing. Don't know if that is even possible, but the only thing I could think of. There is a simple plastic tee that tee's the air going to the pair of diffusers. So it should have had air pressure going to it. The other diffuser was putting out bubbles and ballooned up like it should be - a little more obviously than another station where the air was going out both diffusers.

This thread reminded me I need to go out and pull that diffuser up and see what the problem is. Was leaving the next day and one diffuser was working fine so just left it. Still working a month later.

But back to the cleaning, all mine has been done at the bottom of the pond while in operation. Tapping on it with my hand to dislodge stuff and rubbing the surface. Half way through their second year of operation.

My 9" Vertex's will not fit all the way down in a 5 gallon bucket either- But they fit perfect in a Muck tub from Agri supply places - even better are the blu Beef cattle supplemental feed tubs every beef farmer has a hundred of - they are just right.
However like the idea of removing clamp and cleaning diffuser . That would make it simple.
I will look into that when I have to replace if it will screw into the vertex.

Snrub,

That's great but I have extra issues with extremely hard water and even bryozoans growing on my md's that simple surface scrubbing won't competely address.

What grows on or forms deposits on and under the membrane and on and in the pores of the ceramic air stones is very dependent on numerous variables in each pond. Main variables are depth of diffuser, clarity of water, water chemistry, and the flora and fauna of the pond/lake. Diffusers in higher alkalinity water tend to clog faster than those in soft water.

This diffuser clogging topic points out a good reason to install diffusers so they are easy to lift and clean, yet have just enough weight to hold them on the bottom when they 'balloon up' during operation.

I also think (but have no concrete data) that diffusers that are turned off grow more "stuff" on the membrane (when they are off) than the ones that are running 24/7.

One of the big things that determine if diffusers grow stuff on the membrane is how clear the water is and if 1% of the surface light (euphotic depth) can reach the diffuser. Depth and water clarity have a lot to do with clogging of the diffuser.

The main things that clog the diffuser are algae, other biotic growths, carbonate deposits and or silt deposits. Silt deposits are the easiest to remove from a diffuser. If materials get through the slits of the diffuser membrane, they can coalesce and interfere with functioning of the check valve. Phytoplankton, attached algae, and bacteria are many times smaller than the slits of membrane diffusers and can easily work there way through membrane slits.