Air Stones That Suck

[singularity]

Hi,

I have a number of buckets in DWC, two air pumps, and one to two large cylindrical air stones per bucket that are all fed from common manifolds, one per pump.

There is a fair bit of overpressure from the manifolds and all the line are the same length with the same water levels, so back pressure should be similar, and when accounting for the overpressure, they should all push similar amounts of air.

The problem is that's far from the case. Some stones just blast and from others, a mere trickle.

I am quite certain it is in the stones to blame for the high level of variability in output as they're the only uncontrolled variable, and in one instance I noticed one of them had a tremendous output that was all concentrated nearest the outlet that the hose connects to. They just glue this on and all the air was escaping from around it, meaning that stone was acting as nothing more than as a dead weight while air from the line was essentially free flowing.

I replaced that "bad" stone with a new one where I encountered the exact opposite problem; almost no output, certainly no "flow"... just a few fine bubbles gently floating up of their volition... no drive at all. Useless and disappointing. The other stone in that bucket had great output, so I just left it as it was for the time being.

Then of course you have the issue of having them clog... where output is reduced to a trickle, and I've had that happen once, to the extent the plant was showing signs of being over watered.

So these air stones clearly suck real bad and are a big liability to the potential for success of my grow. Today is the day that I clean out the buckets and .... maybe don't put the stones back?

I have heard of people not using them and just leaving the air line in... I'm assuming they weigh it down somehow.

I get tremendous output if I just stick the line in there and let it blast.

Now, I recognize that "fine bubbles" helps the DO content, but micro bubbles just aren't a happening from this getup.... these stones don't do it.

What they do manage to do, when working properly, is get a real good boil going, providing very good circulation, and the DO content will then be raised not through micro bubbles, but by the drastically increased surface area of the "boiling" surface to air interface + terrific circulation.

I've seen someone post tests with a DO meter that seemed to demonstrate it didn't matter if it was a super expensive micro bubble ceramic type stone or just the open ended hose, they were all saturated.

I have one or two buckets where the stones are just boiling it like mad and the roots don't seem to mind it. But I'm wondering if anyone has encountered issues of too much turbulence slowing root growth or damaging them, say via air pruning.

As well, are there any suggestions as to what could be used to weigh down the airlines? I was thinking of screwing a bolt into the end and cutting a few slits in it just ahead of the bolt to let the air blast out. I suppose the bolt in the water wouldn't be the best idea though.

Also, is it typical to experience such a high degree of variability between new air stones?

Thanks

 

[sedate]

Hi,

I have a number of buckets in DWC, two air pumps, and one to two large cylindrical air stones per bucket that are all fed from common manifolds, one per pump.

There is a fair bit of overpressure from the manifolds and all the line are the same length with the same water levels, so back pressure should be similar, and when accounting for the overpressure, they should all push similar amounts of air.

The problem is that's far from the case. Some stones just blast and from others, a mere trickle.

I'm not sure why you think the backpressure and manifold output pressures are all the same.

Generally, I've found using individual pumps for buckets ameliorates this problem - very small differences in pressure over your manifold - here this can be explained by geometery - really does make a huge difference in output at the individual airstones - generally the more individual outputs on a given pump, the more variability in the air coming off the stones.

What kind of pump are you using?

 

[singularity]

They're all roughly the same because they're all setup identically. Same line lengths, same amount of water, and from the same common manifold which is not like the stock abhorrent contraption.

I'm running 2X GH dual diaphragm pumps, feeding both of the outputs from each one into a glass jar, so one jar per pump. The jar gets pressurized to provide the pump with steady backpressure and act as a shock dampener. That quiets the whole thing down nicely, and of course it leaks a hell of a lot less than the stock manifold.

I have 5 feed lines coming out of each pressurized jar. Four go directly to air stones and the fifth reuses the stock manifold which is now sealed at one end, just for some extra lines.

They won't be perfectly identical but there is enough overpressure that it shouldn't matter. I base this judgement on the finding that one "bad" airstone, which lets all the air out nearest the nipple instead of through the stone itself, boils the bucket like crazy without reducing pressure in the others. But then you want "fine bubbles", or at least finer, so I replaced that "bad" stone with two different "good" ones of the same variety. Neither of which offer anything more than a faint trickle.

So it seems like the greatest source of variability by orders of magnitude here are the stones themselves. On top of that they just don't seem to be needed, or very useful.

I run these pumps inside of an insulated box in order to quell the noise from them, so they get a bit hot because of that, but on the up side I don't hear them at all and they seem robust enough to take the heat, which is lost through the lengths of line, mostly.

I figured 8X cheap pumps would have been louder and harder to stifle?

I see your point though.

PS: The stock manifold that comes with the pumps leaks like a sieve right through the valves which are obviously of poor quality. Garbage like that will certainly cause a high degree of variability as they won't all leak the same.. My homemade manifold/shock dampener is leak free.

 

[hempster333]

Hi,

I have a number of buckets in DWC, two air pumps, and one to two large cylindrical air stones per bucket that are all fed from common manifolds, one per pump.

There is a fair bit of overpressure from the manifolds and all the line are the same length with the same water levels, so back pressure should be similar, and when accounting for the overpressure, they should all push similar amounts of air.

The problem is that's far from the case. Some stones just blast and from others, a mere trickle.

I am quite certain it is in the stones to blame for the high level of variability in output as they're the only uncontrolled variable, and in one instance I noticed one of them had a tremendous output that was all concentrated nearest the outlet that the hose connects to. They just glue this on and all the air was escaping from around it, meaning that stone was acting as nothing more than as a dead weight while air from the line was essentially free flowing.

I replaced that "bad" stone with a new one where I encountered the exact opposite problem; almost no output, certainly no "flow"... just a few fine bubbles gently floating up of their volition... no drive at all. Useless and disappointing. The other stone in that bucket had great output, so I just left it as it was for the time being.

Then of course you have the issue of having them clog... where output is reduced to a trickle, and I've had that happen once, to the extent the plant was showing signs of being over watered.

So these air stones clearly suck real bad and are a big liability to the potential for success of my grow. Today is the day that I clean out the buckets and .... maybe don't put the stones back?

I have heard of people not using them and just leaving the air line in... I'm assuming they weigh it down somehow.

I get tremendous output if I just stick the line in there and let it blast.

Now, I recognize that "fine bubbles" helps the DO content, but micro bubbles just aren't a happening from this getup.... these stones don't do it.

What they do manage to do, when working properly, is get a real good boil going, providing very good circulation, and the DO content will then be raised not through micro bubbles, but by the drastically increased surface area of the "boiling" surface to air interface + terrific circulation.

I've seen someone post tests with a DO meter that seemed to demonstrate it didn't matter if it was a super expensive micro bubble ceramic type stone or just the open ended hose, they were all saturated.

I have one or two buckets where the stones are just boiling it like mad and the roots don't seem to mind it. But I'm wondering if anyone has encountered issues of too much turbulence slowing root growth or damaging them, say via air pruning.

As well, are there any suggestions as to what could be used to weigh down the airlines? I was thinking of screwing a bolt into the end and cutting a few slits in it just ahead of the bolt to let the air blast out. I suppose the bolt in the water wouldn't be the best idea though.

Also, is it typical to experience such a high degree of variability between new air stones?

Thanks

I would suggest a different way to oxegenate the water its called a Vortex does a much better job but expensive at least $400 airstones clog very easily used them for years Thewaterbrewery.com

 

[singularity]

Thanks for the blender spam.

Back to the subject at hand though. I wonder if the airstone also might be too large for the pump capability. These chinese manufacturers and importers, which is all of them it seems, rarely if ever offer proper specifications.

How the hell can you properly match up a stone with a pump without a minimal or recommend pressure or flow rate?

In terms of stones clogging easily it seems it's because there isn't enough pressure or flow rate behind them to keep them clear of water and so they're half saturated at any given time.

This becomes obvious as it seems I get little output from them, until I pull them out of the water and allow them to blow the water out for a good 30 seconds. Dropping them back in after that produces substantial output.

Of course sometimes the stones just seem to have a low output and there's nothing to do about it.

Seems like the wise and maybe necessary choice then is to slice the air line ahead of the stone to let the air flow out of and let the stone act as a dead weight in which to house beneficial bacteria.

 

[reeldrag]

eco air discs work well in 5 gallon dwc but only if u have a good pump I would also suggest a differant pump get an eco air 5 COMMERCIAL pump they run about 80 bucks but work awesome I ran one 24 -7 for about 3 yrs before it went tits up on me. part of your problem u r having with the round air stones is how they r made nothing u can do about it but buy 3 times as many as u need and just weed thru the bad ones.

 

[singularity]

mmhm.... yeh. I went with the GH dual diaphragm pump because it was supposed to be quiet..... it isn't really. But the piston based pumps are not known for quiet operation at all. Valves and pushrods are just going to be noisier.

I had to build a housing just to muffle the noise from the GH, otherwise it would have been intolerable, and unsafe. I don't know if my little housing would be at all sufficient to operate a pump that's 10X noisier.

Given the lack of available comparative product/setup information I'm kind of forced to fly blind there and I can't afford to try everything under the sun. What I have now is going to have to work for awhile.

Having said that:

What I had ordered was Ecoplus large cylindrical air stones... and what I got was Hydrofarm Active Aqua Large cylindrical air stones. I don't consider them equivalent because the later uses a ton of sealant around the nipple which is also of a different style.

The later is priced higher, while I got it for the price of the ecoplus.... but that is cold comfort if it's of greatly reduced quality despite whatever price it goes for. I'm not sure if I should take the issue up or not. Does anyone have experience with both varieties? Are they equally bad?

 

[Bombadill]

I find the RENA 6" ceramic air stones do a good job of releasing very tiny bubbles evenly across the air stone:
http://www.rena.net/Products/Product.aspx?ProductID=100

Good luck finding them anywhere but online, but they are a nice solid ceramic that doesn't fall to pieces like the blue kind.
The end caps even come off so the inside can be cleaned with a bottle brush.

 

[singularity]

That looks like an interesting product, probably because like some of the other ceramic "micro bubble" stones, that are so damned expensive, they're likely subject to a better manufacturing method, producing a more uniform product, not only across the part itself but the manufacturing spread as well.

What I dislike about companies like this though is that I can't buy the part directly from them/website. Instead we're forced to have some middleman gouge us just for the sake of taking our damn order.

I just looked it up and this one is 6.89 at some online pet store, so it might be worth a try. Thanks for suggesting it.

In other related news..... these "micro bubble" stones are bs in terms of micro bubble ability from what I've gathered. I've read scientific studies that conclude the bubble's size is largely irrespective of the hole/outlet port size. Smaller holes result in the same size of bubbles. Smaller bubbles are only creating through things like shearing forces, either via fluidic oscillators or some other introduced turbulence.

Pretty damn sad and pathetic to see "micro bubble" air stones that cost 100 dollars or anywhere close to it, because maybe they're a little more homogenous and reliable, and the cheaper alternatives suck so bad.

The Rena part, at this price, is certainly interesting. Thanks for suggesting it.

 

[freshgardens]

Whats up man. I had a similar issue and my buddy told me all of my tubing has to be the same length or the air wont circulate properly. Hope this helps

 

[singularity]

Whats up man. I had a similar issue and my buddy told me all of my tubing has to be the same length or the air wont circulate properly. Hope this helps

That's because the tubing is a resistance to air flow, and so the more tubing you have the greater the resistance to airflow.

It then stands to reason, if you have all different lengths of tubing, you will have all different resistances to airflow, and the air will seek the path of least resistance, as does everything.

So yes, they should be equal, and this "could" cause an imbalance in output, but ONLY, if it represented the weakest link in the chain, as it were.

Another source of imbalance would be, for example, if you allowed all different water levels in each bucket. Clearly that would create rather large differences in resistance to air flow. Most likely it would create a far greater source of imbalance than would a few inches difference in tubing length, or even a few feet. At that level, differences in tubing length are small, and are very small compared to the differences in resistance/back or head pressure, caused by different water levels.

You need to have an over pressure condition where there's enough headroom to ensure that there's always output regardless of a difference of a few inches of water from bucket to bucket, or you need individual pumps.

Anyway, I can assure you that my tubing length was a fixed constant, and so were the water levels. That leaves only one culprit for the very drastic differences in the resulting air flow and that is the subpar quality airstones. Maybe when they press them together they don't care if the pressure is off by 50lbs from the last batch if the temperature they're doing it at is off by 15 degrees and so on, but the end result is a different in density and a difference in homogeneity that absolutely trumps the minute differences in resistance to flow caused by a minor tubing length variations and even one that trumps the more obviously larger back pressure differences caused by differing water levels. That means these airstones fn suck an order of magnitude larger and are definitely the weakest link bar none.

We should demand affordable products of higher quality and we should speak loudly against those which are found to be insufficient, or we'll never get anything at all decent.

Also, cheap airstones aren't so cheap if I have to buy in bulk at no discount just to bin them for basic useability myself.

 

[woodsmaneh]

Well I think you need another source for air stones. I have run tests on everything out there and my buddy Leaglyflying has done his own tests. Cheap blue air stones work best. I order 144 at a time online and never have had a bad stone , broken yes bad no. They do have some degree of variation but not real noticeable. I am running 36 six inch stones with a 388 watt pump and no problems. I only use them for one grow than toss them out, I have found that the nutrients will cause them to crumple after 4 months so out they go every grow.