GH Dual Diaphragm Air Pump, aka Blue Stone Air Pump; Tips and Tricks

[singularity]

Hi,

I've seen a lot good said about these pumps and decided to go with them for my purposes.

One thing I kept hearing about is how quiet they are. I guess "compared to what", is the question, as well as perhaps "under what circumstances", would be another.

One thing I quickly discovered is that the air manifold on them leaks like a sieve. Not so much from the joints where the hose hooks up to the manifold, but all around the adjustable air valves. If any air is allowed to escape here, noise comes with it. The noise is from the dual diaphragms hammering back and forth in tandem at line frequency, and so it has the the capability of being disturbingly loud.

In addition, one method people seem to speak of to quiet their pumps is to suspend it by some shock absorbing cord or hang it by its own cord in order to ensure it doesn't transmit vibrations into whatever it's sitting on. This can and should probably be largely disregarded, because the first step must be minimize the noise it's creating at the point it creates it, stop the very source of the noise, and then worry about muffling what's left of it later. Essentially you don't put a band-aid over a knife wound without at least first pulling out the knife.

While I was playing around with it I quickly discovered that tilting it was a very bad idea. The "connecting rod" between the dual diaphragms is rectangular and housed between transformers in a gap that's too narrow to allow clearance for it to rotate, but that doesn't prevent it from trying!!!

What you have then is obviously the shaft grinding up on the sides of the transformer and that makes the pump very loud indeed. The only way I see to avoid that, is in keeping the pump level, such that the center of gravity on that shaft works to prevent it from rotating rather than the opposite.

If yours is making a hammering sound, you need to take it apart and center that shaft.

Now, back to the air leak issue. I didn't spend good money on all of this pumping power to have it leak anywhere, where it's doing no useful work for me, and instead works against me by alerting neighbors, for example. This is intolerable.

After some quick research I found a method that seemed to make a lot of sense, tested it out for myself, and it works like a charm.

Basically, you use a glass jar, which is very stiff and won't be inclined to vibration by the pump, thereby very effectively containing the noise from it inside the jar. The jar needn't be any larger than a typical Mason jar, but it could be as large as a pickle jar as well. Preferably you would have a jar with a plastic lid, instead of a thin metal one. Thin metal lids will be prone to rusting very rapidly, leaking, and not as completely effective at damping noise.

All of your hose inputs from the pump, and hose outputs to the airstones, need to go through the lid. So it helps to have a lid with a large enough area to accommodate them all.

I am using several little honey jars, slightly smaller than a Mason jar and maybe a bit wider, with a plastic lid. This gives me enough room to drill 2 holes that accommodate the 1/4" inputs from the pump, and at least four 3/8" outputs.

If you use good drill bits, start small with pilot bits and work your way up to the final size, you'll get very accurate holes. The accuracy helps in keeping them from getting too large, and too out of round, that would create a poor seal.

The nice thing here is that the hoses are much softer than the lid, and we can use this to squeeze the hoses through a smaller hole, creating an interference seal which doesn't leak at all. This to me is far superior to having to try relying on any kind of a sealant or glue.

I think it's probably imperative to have both outputs of the pump feeding into a single jar, just as they do into a manifold. This provides each diaphragm with required backpressure which should provide for optimal operation efficiency, as well as for maximum noise and vibration damping. The diaphragms work in tandem and so should be damped the same.

If you used separate jars for each output, then you will end up with unequal loading for each side of the pump which is going to create stress and with it additional noise, and reduced reliability. You don't want the fragile diaphragms to have to absorb such shock, instead you want their loads as balanced and as tame as possible to generate the least stress on them to begin with, and use the air compression/damping ability inside the jar to snuff out the rest, whilst containing whatever is left over.

If you have additional lids then you can make up additional combinations of outputs. What I intend to try next is a quarter inch feed from the first jar into a second jar that will have additional 3/8" outputs for more airstones and possibly another piggyback jar which will have a 1/4" compression loop with that same leaky air manifold that I previously removed, just in case I really need adjustability. This is obviously not as ideal since they do leak and will continue to, but noise from the diaphragms hammering back and forth at line frequency should be completely damped by then that it won't be a bother, and their slight leakage will just be a tradeoff in not having to have X^n lids with every conceivable hole pattern if I just need some air to evaporate chlorine out of a bucket of water or whatever. You always have to give something up for additional convenience.

Another nice component of this setup is it allows you to pre filter the air flow, rather than letting your airstones serve double duty as air filters and get clogged up in short order.

I've already tested water filtering in a bigger jar, like you would with a bong. It works but I think the water only so effective anyway and makes it louder than it needs to be. Ice in the jar to cool the airflow is a complete waste.. Having the ice agitated by the air stream and rattle against the side of the jar makes it louder than anything, and any cooling that takes place is rapidly lost to heat in the airline likely within the first few feet, such that by the time it hits the airstone it's at ambient temp and so it can't cool the bucket, but I tried it for science.

I think what I'll do then for filtering is cut a cheap open cell foam sponge into a disc shape such that it fits into the jar as a diaphragm, and feed both air hoses through it into the bottom of the jar. The outputs will sit above the sponge on the top side of the jar, so that the airflow is forced through the sponge and the crap will collect in the bottom. This will filter the very worst of it, without impeding airflow at all. The airstones are obviously much finer than the smallest particle sizes that the sponge will pass, so they will still get clogged but hopefully not as fast.

One has to realize that airstones getting clogged this way is a source of contamination and potential for infection. If all of the air going to them passes through this single checkpoint that we have easy access to, then we can treat it.

Speaking of checkvalves, I think it's also possible that the jar, so configured, could act as one.

Lastly, I would like to note that the airflow is no hotter than ambient, either, and so this metal encased diaphragm pump is a good design from that perspective.

When I first tested this pump it was far too loud to live with and I thought I wouldn't be able to use it, but the jar damper renders it inaudible from the next room and it's more likely that the sound of the bubbles will be louder.

 

[Aerojoe]

Essentially you don't put a band-aid over a knife wound without at least first pulling out the knife.

Actually your supposed to do that man, many people don't know and pull the knife out first which could've been keeping you from bleeding out, in my first aid book it says to bandage over the knife. Back to the topic at hand seems like w/ all the work your doing exactly what you set out not to do. Is there a reason your loyal to this particular brand/design of pump? IMO just return it and get one that doesn't have those problems, what about an active air? I own one and they cheaper and apparently better cause they don't leak or require me to put them into jars.

 

[singularity]

Actually your supposed to do that man, many people don't know and pull the knife out first which could've been keeping you from bleeding out, in my first aid book it says to bandage over the knife. Back to the topic at hand seems like w/ all the work your doing exactly what you set out not to do. Is there a reason your loyal to this particular brand/design of pump? IMO just return it and get one that doesn't have those problems, what about an active air? I own one and they cheaper and apparently better cause they don't leak or require me to put them into jars.

All the same, it deviates from the intent of the analogy, which is that you have to address the source of the issue, rather than the symptoms of it. That's always the effective and optimal route. If you just patched bandages around a knife, left the knife in place and called it fixed, it will only continue to bleed and soak through them, while continued damage is caused by the knife as well.

As it relates to the air pump, if you hung it by a cord and/or stuffed it inside an insulated box, then the rotated drive shaft knocking and grinding against the transformers is going to hammer itself apart in short order.

Fix the shaft alignment, then it won't hammer itself apart, and you won't even need to hang it, which causes the shaft alignment problem. Given this nature of the design, there should clearly be a warning in the instructions to only operated it on a level surface in order to avoid that problem, but I don't think there is one.

Where do you get what I set out not to do from? Low noise was a critical function, adequate airflow another, and lifespan as well. Cost was also certainly a factor. Based on the available information, it met those requirements. Based on actual testing, it failed the low noise requirement, until I resolved it.

Part of that resolution was specific to this model, and part of it is general and useful to any model. I would not be too quick to infer a brand loyalty from that.

As per the type of design, yes, it's easy to imagine a "good" industrial quality diaphragm pump will have certain advantages. One being the capability of being rather quiet, given adequate output, as well as frictionless, which should add very little heat to either the airstream or the room.

It's exceptional in that regard. After running for an hour into a bucket filled with about two gallons, the water temp was no greater than ambient, the same as the control bucket, and the pump remained cool to the touch, with no additional cooling for it required.

I'll be able to get countless hours of virtually wear free performance out of this thing, extremely reliably, and that is kind of important. I believe the noise and shock dampening jar that I gave it will help extent the life of it as well, since it actually acts to dampen the shock of the drive shaft motion. Less shock and stress simply equates to a longer lifespan for all components involved, and people generally don't seem to complain about the lifespan of it already.

What about an active air? It's in the right price range, and output seems respectable, but wrong design for my liking. The piston will add friction, creating heat and wear. While no useful sound measurements are available for either of them, a typical failing of industry and reviewers alike, and lacking the ability to test them ahead of time, I'm a vulnerable to the information that I can find about them. This was the reason of my post, to put better information out there.

Research of these will show a general consensus that they're loud as hell, enough that they are run outside, in the garage or basement, with the line running X feet into the grow room, just to handle the noise. But that doesn't really handle the noise if your neighbors end up suffering it, or if you don't have that option at all. It's a terrible band aid for the symptoms of it. What's more, it throws away a lot of output with increased head pressure the longer you make the run from it just to move the noise to be someone else's problem. My lines will be no longer than 5' long since I can tolerate their noise levels now, and their output will be an even flow.

Also I find it highly likely that any valve manifold, probably from the very same factories in china, will suffer the same leakage problems. That's attributable to the manifold only and not the pump itself. It is possible that there are other manifolds /splitters that I could try, but I don't need their added cost right now. Anyway, as previously mentioned, the damping action of the jar is helpful to the function of the diaphragm mechanics anyway, which a better sealed valve would not be by itself. It's beneficial in more ways than one.

So despite those few issues, which are easily worked around, it's still a strong and capable pump. I will be able to run a few of them in the next room and not hear them at all from either the living area, or through the walls. The nature of the post is to let people know that it can be that good a pump, but probably won't be without a little extra work on their part. The damping jar/manifold would be of great value for any diaphragm based pump, particularly of the dual variety. I think the option to filter the airstream could be invaluable too. BTW, your active air pump that you linked to is 15 dollars more than I paid for the blue stone pump.

This isn't at all a sales job for this type or brand of pump, but to help you make the most of it if you happen to have one. I personally can't just return it and get something else anyway, but after having tested it with the jar there is no inclination to.

 

[Aerojoe]

All the same, it deviates from the intent of the analogy, which is that you have to address the source of the issue, rather than the symptoms of it. That's always the effective and optimal route. If you just patched bandages around a knife, left the knife in place and called it fixed, it will only continue to bleed and soak through them, while continued damage is caused by the knife as well.

This isn't at all a sales job for this type or brand of pump, but to help you make the most of it if you happen to have one. I personally can't just return it and get something else anyway, but after having tested it with the jar there is no inclination to.

I'm not saying you were trying to do a sales job for the pump, I'm simply saying if there's no brand loyalty, why not try a different one or the one I suggested it's fairly silent at least imo when I hang it from a stable piece of wood, it was a bit louder when sitting on the rubber feet, the other reason I suggested it was I was able to buy it locally for a lot cheaper. My info about the bandage around the knife was meant to be what you do till you can get professional(hospital/doctor) help.

 

[singularity]

Yeah well, "fairly quiet" means a lot of nothing, no offense. We really should be pressuring industry to give us quantifiable information in that regard since most of us don't get to test them and stealth is often a huge factor.

I was originally looking into that type of pump given their output, but most every comment on them was that they were fairly loud, or very loud. I also don't have a local supplier where I can just bring it back to. Mail order purchases aren't even returnable.

Anyway, the pumps I have went from being a big regret to a purchase that I'm fairly content with once I saw how I could silence them.

 

[Aerojoe]

Glad to see you got your problem under satisfactory control, I tend not to order online for that exact reason. Trying to get warranty online at the very least will be painfully costly on time/shipping. If my ballast/pump/fan breaks I usually need a replacement ASAP.

 

[singularity]

Glad to see you got your problem under satisfactory control, I tend not to order online for that exact reason. Trying to get warranty online at the very least will be painfully costly on time/shipping. If my ballast/pump/fan breaks I usually need a replacement ASAP.

Oh for sure. Wouldn't it be so great if I could not only go to a brick and mortar to see the products, but actually one that demonstrated them such that you could make a truly educated decision, and even stood behind their products. Alas, t'aint the reality du jour at all. Maybe some of them exist somewhere, and I bet their prices are stupendous as well, you know, despite always hearing about these amazing deals the local giveaways were.

I'm of the opinion that a large portion of industry thrives on making warranty work, shall we say, uninviting. People are more likely to just get a replacement and pawn off their useless junk on someone else, lying about how little it needs to be fixed if you just know someone who's handy that can give you a deal on it.

Then you look at what load of bs we're served as marketing info, often providing no useful information at all, and often different specifications are seen for the same product from one site to another site and as some sites are a front to numerous other sites you can get differing product information from the same site. Try getting any of them to even answer a question, or if they do, to do so usefully. It doesn't happen. Just buy it and stfu already.

Then you look at places like these.. not much better. Some give useful info, and others detract from it, and it seems impossible to tell who is who anymore, so it's all just noise. Some are truly absurd, where opinions are imposed via moderation and polluted with ad revenue.

Some youtube videos are useful in giving product comparisons, tests or demonstrations, but there's often no real basis for comparison, no control, reference or standards. Like this GH pump can be seen tested there, and it seems acceptable in the noise department. But I promise you when you pull it out of the box, at least based on my experience, it's going to be louder.

You can't decide by the average of the sum of opinions either because there is so much noise and so many people just parrot what some others have said without actually knowing for themselves, and so we see false consensus and confirmation bias.

It's absolute hell and that's probably why it took me a year to put an order together. It also took me a few tries to find a place that would take the order. A particularly interesting complication was that it was cross border. Buying within the country was out of the question because everything was 2X or 3X the price. Most places just didn't want to mess with it, some said they would and then changed their minds at the last minute, wasting a month of my time and more. The end result of finally finding one is that there is no warranty through them and all sales are final. Sure, I could have taken pains to contact blue stone to see about that rattle. Only I violated that warranty when I opened it up just to see what the problem was, and tore the hymen on it.

They want to protect themselves of course but if it's something simple like it turned out to be then you have to be an idiot to take the trouble and time of trying to get a warranty repair done when you could fix it yourself in two minutes.

Anyway you can probably imagine that I really did my homework despite the poor quality of product information available, and part of my method was always to spend that little extra on what seemed like higher quality, to help ensure that I in fact get it, and so wasn't completely wasting my money on things I would be stuck with that wouldn't work.

In terms of ballasts, pumps, fans, I didn't go cheap. I think I got really good deals on what I did get too. I also got two pumps for a little redundancy. Two ballasts as well, which are well made, quiet and will be reliable =harvest elite pros. I'm not saying they couldn't be of higher quality, but more expensive ones by far don't specify the use of higher quality components, and so all you know for certain is that they have a higher price tag.

The tent that I got was a steal considering what similarly sized models go for. Fan is Ostberg, good quality, UL listed, and one of the very few that actually provides full specifications. I expect it to last a very long time.

In the end I think I got great equipment and at really good prices, comparatively. Had I been able to go to a brick and mortar I'd have paid through the noise and probably just been stuck on whatever junk they had in stock on the promise of a warranty and the leisure of convenience.

After having gone through the process though all I can say is that manufacturers need to do a hell of a lot better in providing useful specifications, which are often completely absent.

Also mail order is a real pita, where shipping fees quickly become absurd, especially if it's just for a few items. But you gotta do what you gotta do.

My only problem now is that I'm not sure if I want to use all of this stuff in the middle of the summer when I have no AC. I'm so very tired of waiting though..

 

[Aerojoe]

Hey man, are there no hydro stores in your area? If your not in a medi state, I can understand. The reasons I prefer to buy locally when I can, is I like to support local spots, they give me good competitive pricing, they have and stand by there warranties. If something breaks I can go exchange or get loaner whilst they fix the prob. They even loaned me equipment for a season before, because I couldn't afford it. I hope I will be able to afford it one day... Thanks guys, you know who you are.

 

[altitudefarmer]

Anyone know about a rebuild kit for these pumps?