Pond Boss Forums AERATION Systems questions Diffuser cleaning

Just an FYI.

Was scuba diving in pond yesterday to install some permanent moorings for boat fishing. After finished and observing fish for a while, somewhat of an afterthought, decided to look at the diffusers and see how they were doing. Have three dual Matala 9".

Glad I did. Had an eight inch of crud over a lot of the surface. The first two were still passing air fine, but notice slightly better air flow after rubbing the surface and tapping on the balooned out surface with my hand. But when arrived at the north diffuser, the left of the pair only had air coming out about a third of the area and the right side was also heavily encrusted. A lot more air flowed after cleaning.

These diffusers have been running constantly since spring.

So if your diffusers have been in the pond a long while, might be worth checking them. Most people will not have the option of going under water and viewing them in operation (kind of cool, by the way), but pulling them up by rope might also do the trick.

Many places sell membrane diffusers and say they do not need cleaning. I do not agree and it is always a good idea to periodically pull them up and scrub them off. Numerous types of things can contribute to the pores clogging even as in Snrub's case operating them 24/7 clogging can still occur. Aeration will be a lot better when diffusers are cleaned annually.

IMHO, Cleaning every year should be on the maintenance list weather stone or membrane.

I pulled this diffuser up in my biggest pond and it had bryazoans growing on it.







This stuff is really tenacious and also grows on my cages. Another reason I don't do cages anymore.

I did not have the stuff like around the outside edge in your picture, but the center of the diffuser looked just like yours. And on one of the six disks, was bad enough to stop flow over a considerable portion of the disk. Had to rub and tap pretty hard under water to get it cleaned off.

I had to look up Bryozoans to see what they were. Some in ocean water can be bad to handle.

Bryozoans

Just a note on 9" round Matala membrane diffusers.

I have three, double 9" stations. This year I had two of the stations have one of the diffusers stick shut. Air was only coming out one side of the dual diffuser. I discovered this while cleaning them. I was diving down with a dive mask and fins, breath holding, and rubbing the diffusers with a golved hand to clean them. Did not make sense why the diffusers were collapsed and no air coming out one of the two disks.

Rather than pulling them at the time and finding out the problem, it was late summer and I just figured would let them run with the single disk till fall when I would pull them up to see the problem. They were still moving a lot of water with the single disk and the heat of summer was over anyway.

Got around to pulling them up today.

What I found when I unscrewed the disk was that the built in check valve had stuck in the air opening. The way these membrane disks are designed, when air pressure stops the disk center has a slight protrusion that covers the air opening and acts as a check valve so water will not enter the air line. It works. I have never had a problem with this check valve sticking in the past. But upon inspection the center protrusion had been forced down into the air opening enough so the modest air pressure would not re-open the valve. So all the air was directed to the other disk.

In retrospect I think I created the problem. I remember pulling the air lines off at the compressor a couple times and putting it back on to "shock" the membrane and potentially clean some of any build up off. I think in doing so the membrane slammed down hard enough to stick the check valve protrusion into the air opening. After I unscrewed the disk off the housing it only took a tiny bit of pressure of a blunt instrument into the air opening to un-stick the membrane. Almost no pressure. So it was not stuck very bad at all. But with the compressor only running about 4.5 psi it was not enough air pressure to open it. Knowing what I know now I will: 1. not remove air lines from the compressor and let the water pressure slam the membrane shut against this built in check valve and 2. if it does happen again will use an air compressor source with enough volume and a temporary "burst" and the stuck membrane should open easily.

I think with the CFM I am supplying, the dual disks are only marginally better than running the air through a single disk anyway. Same CFM, just divided between the two disks and bubbles supplied over a broader area. Probably more efficient at moving water but only marginally considering no extra air flow. So I am not too worried if one sticks shut again anyway.

Just an FYI should anyone run into this situation with Matala dual diffusers.

Told DCQuarterCircle I would post some pictures of my Matala diffuser base modifications and thought this thread is as good of place as any.

The Matala bases are nice, good quality plastic. They have a hole to fill them with sand for weight. All this works well.

The problem for me was placing them and being able to retrieve for maintenance. I wanted to be able to let them down with a rope, be able to move them if I did not like the placement, have a rope attached with buoy so they could be located in case they quit working, and be able to pull them out when needed.

The Matala bases had no place to attach a rope. I guess that is fine if you are placing them in the bottom of a dry pond.

I made nice bases out of 2x6 boards to attach to the bottom of the plastic base. Then I ran a rope through holes in the boards first cadi-corner then to all four corners. This worked but not very well. Putting buoyant wood on the bottom of a heavy item tends to make it want to turn over in the water. I got them down, but it was not easy to get them on the bottom without them turning upside down. But it worked for the first year.

My attempt this year was to add eye bolts to the wood, and attaching the ropes above the diffusers with the idea of changing the center of gravity. But I had removed the diffusers for the winter and the boards dried completely out, so they were even more buoyant. Still wanted to turn over and would barely sink. After getting one down that way, the other two decided to do something different.

The pictures below show the final attempt that worked excellent. The changes I made were to take the wood 2x6 structure off and replace it with 15"x20" nylon kitchen cutting board. Not wanting to repeat previous problems I also added the two eye bolts so the center of gravity would be lowered. I also drilled small holes in the Matala plastic base at the upper and lower part to let air out and water in more quickly while trying to sink (they are already full of gravel).

Worked like a charm. Stayed upright and level and easily was able to let the diffuser down to the bottom. Now they can be pulled up for cleaning or other maintenance easily. The cutting board also makes for a larger base so it will not sink into the bottom as far.

The rope attached has a float on the surface so I can easily locate the diffusers and lift them onto my boat if/when needed.

Thanks Snrub! Your description in a related post of your setup about cfm being negligible to two diffusers vs. one is most helpful. I am going to refrain from using a two-disc and only use a single Matala 9" with base for the same reason.

I'll get A poly board for a base and attach as you rigged up for maintenance when needed. I am only going to be pushing a max of about 2.4cfm to it from an HK60L pump through probably 25' of 5/8" weighted hose. I'm itchin' to get all this ordered today, so I REALLY appreciate the illustrated insight of your installation.

Chuck
p.s. Thank you for writing well in your posts.

You are very welcome. I have gained a lot from this forum. I like it when I am able to give back.

Edit:
I think I have figured out what caused one of the two diffusers on the dual diffuser base to quit putting out air. I never had any problem till one time I was trying to clean the diffusers by shocking them by a change of air flow. I had never had any problem shutting the pump on and off to do it. But one time I just pulled the hose off the pump. This allowed the air to rush back out the line at the pump end rapidly. The Matala diffusers have an internal knob on the disk that acts as a check valve. When pressure is released the disk pushed against the inlet in the middle of the disk to keep water from flowing back up the hose. I think what happened is when I pulled the hose off it collapsed the disk so rapidly that the check valve got stuck slightly in the inlet. Since my pumps are running on the low end of required CFM per disk, there simply was not enough pressure to pop the disk back open where it was stuck in the check valve. Once I got it out of the water and put a little more air to it, the stuck disk started working easily. Had I had a pump with more capacity, I don't think I would have had any problem. Lesson learned is that I don't want to remove the hose at the pump and let the membrane collapse rapidly and likely will never have the problem again.

Snrub, I followed your design very closely, and IT WORKS BEAUTIFULLY!

I mounted the single 9" Matala membrane with base full of sand to a good size poly kitchen cutting board, put a SS eyebolt on each corner, tied a rope to each of them, braided that up to a loop, ran a rope through that loop across the pond to carry the diffuser out to the middle with one of us on each end of that rope, and slowly lowered it.

I have a plastic mallard duck floating above it for fun if nothing else, and included a rope attached to the weighted hose to the diffuser so I can retrieve it with very little effort. That retrieval rope is tied to the handle of the cutting board.

I ran a couple of extension cords out to the pump to test it and it all works beautifully! What I am waiting on right now is for Missouri Wind and Solar to get their Suntaqe controller/inverter unit back to me, as the controller side of it failed. I'll report back soon with photos of my setup.

THANK YOU ALL FOR ANY AND ALL HELPFUL EDUCATION FROM THIS SITE ON CONFIGURING AND IMPLEMENTING THIS SYSTEM. I greatly appreciate it! Hip Hip Hooray! TINY BUBBLES 'O PLENTY! (like a big full champagne glass - HA!)

Great! It is nice when a plan works out!

Glad to be of help. And please do post pictures of your setup once it is all going like planned. I would like to know how the controller works out.

Snrub, THANK YOU AGAIN FOR YOUR GUIDANCE ON RIGGING UP THE DIFFUSER! It sinks and works perfectly. Man, this setup is so cool!

To avoid potential problems in the air hose, one very important question I have is: With my 5/8" weighted hose from pump to diffuser (Matala 9" rubber membrane single mount), do I need to have a check valve in that line? If yes, I'll pull up the diffuser to put one in at that end.

Thanks again! I'll include some photos and links to my videos of it as soon as I put in a check valve if I need to.

Many, maybe even most or all, 9" diffusers have a check valve ACTION as part of their design. My Vertex units don't have a check valve per se, but when air is shut off to the diffuser the membrane settles down over the slightly raised center, and acts like a check valve to inhibit water entering the airline.

I don't run check valves on mine, but perhaps others do.

The Matala advertise an internal built in check valve that works as sprkplug describes. The membrane center covers the hole.

Thanks all for getting back to me on the Matala diffuser's built-in "check valve" from the membrane sealing off the end of the hose outlet beneath it. What would be an indicator of this functionality of the diffuser failing? i.e., how would I know it no longer is acting as a check valve properly?

As Snrub requested, here is a video to begin with for my solar aerator setup: https://www.youtube.com/watch?v=6oQ_Xa9p2M4 More coming soon showing all the equipment. The rope in the video is what we used to lower the diffuser. I'll pull the rope from it when I'm sure I don't want to move it again anytime soon. It's poly rope, is it okay to just leave in place? Affect anything at all?

FA rake

This is what I use for mats.

Moving lots of air! Thanks for video.

I leave ropes on mine so I can pull diffusers for service.

WOW! your 1 9" diffuser is pumping way more air/bubbles with way more velocity than my 2 disk setup. What CFM or HP is running through that system? Amazing!

snrub, Thanks for the link to your modified pond scum scraper! Man, that's GREAT! I'll show you a video my Honey took of her son and me(the gimpy one) dragging FA off the top with a green plastic net fence piece. It is too short to easily stretch across the whole pond. We just hooked garden rakes into it and dragged it along.

The fence was given to me in two short pieces. Well, it sort of works fair enough for what I needed it to, as you can see from this video: https://www.youtube.com/watch?v=31QONcOLxQY.

I hope to find a way to get a handle on this algae someday eventually. But aeration is a great starting point from what I've learned through tons of reading and watching videos. More on my opinion on MY aeration setup soon.

Thanks to all who post educational, insightful, helpful info here for all of us to learn from.

Snrub, please excuse my ignorance, but what do you mean by "mats"? Matala diffusers? mats of algae? I expect you mean the latter, as that is what you are using the big rake to pull in, but I just want to be clear on what you refer to.

I also included a rope that is attached all along the air hose out to the handle cutout of the cutting board diffuser base platform. I ran the rope along the hose so I'd never have to pull the on the hose itself directly.

The visible cross rope that runs connects to a loop at the diffuser itself was only used to carry it out to the center of the pond and lower it. I can and will pull that out if necessary. No harm no foul leaving it there, but not necessary to have in there either.

Canyon, Thanks for the excitement and compliment! I'm running a Matala (Hakko) HK60L pump through 55' of 5/8" ID weighted air hose in (wild guess on depth here) approximately 6'-8' deep water from shore to the single Matala 9" diffuser. Of course, it makes perfect sense depending on what pump you are using to your dual diffuser setup, that it would seem to put out less bubbles/velocity than a single diffuser. Only way to match that performance is increase your pump size enough to equal dual disc to a single disc output from a lesser pump size.

It's a beautiful sight when the sun is high and bubbles are seriously churn'n out. Too bad sunlight is so intermittent and solar panels are painfully, and much to my surprise VERY sensitive to ANY interruption to that direct sunlight.

Disappointingly, just the right amount of clouds and this puppy decreases to occasional burps of a big bunch of bubbles now 'n then. (Cool thing though of course is Missouri Wind & Solar's Suntaqe unit turns it right back on automatically!) Otherwise, I'm wishing I would have run grid power down to it at least as an alternate source for constant pond aeration activity. It's never too late to implement that option, but would need to really justify it before delving into a power run to the pond.

I honestly cannot imagine intermittent bubbling will benefit the pond in any way at all. Colorado is one of the sunniest states in the nation, but this summer is challenging that claim. And challenging my satisfaction for this solar setup to aerate a pond sufficiently.

Anyone's thoughts and input on substantiating viability of a solar aerator system that does not run all day, i.e., not in the dark, I'm all ears here. If needed, it would be no small feat to get house power down to the pump, but possible, yes.

DC, running a 1"-1.25" poly tube a couple thousand feet is far less pricey than wire!

Thanks Rainman.

It has little if anything to do with cost, and more so effectiveness of pump over a given distance/drop/hose diameter, etc. I'll revisit where I was previously before implementing my solar aerator system, when I had both options of running a power line to the pond vs. solar designed on paper to compare. Now I'll add to that the option of running an air hose from near the house to the pond as well.

I'll likely have questions here about friction, distance, altitude drop, pump size, hose size, etc. soon to seriously consider that option instead or in addition to what I have now. We'll see. Thanks again for your response!

Mats of algae. Internet comes and goes where I'm at and was trying hard to get that short post made. Had to try several times retyping each time. Does not help I'm using a Tab rather than a computer with keyboard. Sorry for the skimpy explanation.

For algae control measures, what time of year ought I look to release Common Pleco, trapdoor snails, or whatever kind of algae eating critter in my pond? It never freezes over, has a couple of year-round springs feeding it, and is chocked full of algae pretty seriously.