Quantitative Airstone Test. an end to the hype

Thought I would drop in on this thread and drop a little observation. While I think I was able to show that it's pretty easy to hit max DO with any little pump, I have to say that in a DWC setup, really overdoing the amount of air yields great results! While many will say the startibg point is 1 watt per gallon of water, I recently ran 4 liters per minute per gallon in my early veg tote and the plants really exploded. The water was a frothing monster but the plants absolutely loved it!

So for those starting a DWC system, I would really advise spending the little extra coin and getting a BIG pump.
Cheers

legallyflying said:

Thought I would drop in on this thread and drop a little observation. While I think I was able to show that it's pretty easy to hit max DO with any little pump, I have to say that in a DWC setup, really overdoing the amount of air yields great results! While many will say the startibg point is 1 watt per gallon of water, I recently ran 4 liters per minute per gallon in my early veg tote and the plants really exploded. The water was a frothing monster but the plants absolutely loved it!

So for those starting a DWC system, I would really advise spending the little extra coin and getting a BIG pump.

Cheers

Click to expand...

Yes it does. I cant even begin to tell you how big my rootball would get because I would blast some buckets with 3 air stones and some with 4.. I would literally get waves in my buckets but the plants were huge.

Word. I was using a 110 L/M pump to aerate 12 4 gallon buckets (with 3 gallons of water in each). Which is basically 3 liters per gallon of water/ minute. I added another 110L pump in order to have a failsafe backup and double airflow. The plants really like it.

Yup the great thing about using an air pump and stone setup is you can not over oxygenate the water. As a side note to much DO will kill a plant but to do that you need about 15,000$ worth of equipment. The University of Gulph in Canada has a research paper on it. I like using the 9" EPDM pond aerators. Low pressure to boot, never clogs a bizillon tiny bubbles.

[FONT=Arial, Helvetica][SIZE=-1]FlexAir™ disc diffuser bodies are made of high strength polypropylene with 3/4 ” MNPT connections. Each diffuser has a minimum of 6,600 engineered air release orifices, which is up to 20 percent more than comparable models. The special design of the EPDM membrane, with its engineered thickness taper, results in full utilization of the membrane surface, even at low airflow operations. This results in improved oxygen transfer efficiency, along with maximum operational flexibility. The disc diffuser has an integral “triple” check valve to prevent fluid back flow. Normal airflow range is 0 to 5 cfm. Resistance is about 10” H2O when clean. FlexAir™ disc diffusers in stock have fine bubble EPDM membranes installed and weighs 2 lbs. Made in USA.
[/SIZE][/FONT]

woodsmaneh! said:

Yup the great thing about using an air pump and stone setup is you can not over oxygenate the water. As a side note to much DO will kill a plant but to do that you need about 15,000$ worth of equipment. The University of Gulph in Canada has a research paper on it. I like using the 9" EPDM pond aerators. Low pressure to boot, never clogs a bizillon tiny bubbles.

[SIZE=-1]FlexAir™ disc diffuser bodies are made of high strength polypropylene with 3/4 ” MNPT connections. Each diffuser has a minimum of 6,600 engineered air release orifices, which is up to 20 percent more than comparable models. The special design of the EPDM membrane, with its engineered thickness taper, results in full utilization of the membrane surface, even at low airflow operations. This results in improved oxygen transfer efficiency, along with maximum operational flexibility. The disc diffuser has an integral “triple” check valve to prevent fluid back flow. Normal airflow range is 0 to 5 cfm. Resistance is about 10” H2O when clean. FlexAir™ disc diffusers in stock have fine bubble EPDM membranes installed and weighs 2 lbs. Made in USA.

[/SIZE]

Click to expand...

Sup man, how long have you had that [SIZE=-1]FlexAir™ disc diffuser[/SIZE]. Are you sure it cant clog? im looking for one that never clogs, im so tired of clogged air stones. I was about to get this one below but I came across this one , so Ill wait till i get your review on how long youve been using it for & if its clog proof & if you recommend it still

thanks


Word seems to be that this one will never clog cuz its silicon and expands a little to let the air out:

[TABLE="width: 700, align: center"]
[TR]
[TD]Silicone Rubber Diffuser Hose
[/TD]
[/TR]
[TR]
[TD="bgcolor: #339966"]
[/TD]
[/TR]
[TR]
[TD][/TD]
[/TR]
[TR]
[TD]

Application:

• Aquaculture aeration

Features and Benefits:

• Durable, lightweight, resilient silicone rubber
• Resistant to low/high pH, corrosion, crack or burst
• Light to moderate ozone resistance
• Easy to install, reshape, reposition, remove and storage
• Can be laid to form variety of patterns, allowing high coverage area with
  long hose length
• Designed for even distribution of air bubbles along the entire hose
  length
• High oxygen transfer
• Resistant to clog and with self cleaning ability
• Low pressure loss
• Low air pump power requirement
• Suitable for intermittent or continuous duty application
• Back flow resistant
• Offer years of durable and clog free service compare to traditional black
  rubber hose

Specification:Example:General Installation Guide[/TD]
[/TR]
[/TABLE]

Big P said:

Sup man, how long have you had that [SIZE=-1]FlexAir™ disc diffuser[/SIZE]. Are you sure it cant clog? im looking for one that never clogs, im so tired of clogged air stones. I was about to get this one below but I came across this one , so Ill wait till i get your review on how long youve been using it for & if its clog proof & if you recommend it still

thanks


Word seems to be that this one will never clog cuz its silicon and expands a little to let the air out:

[TABLE="width: 700, align: center"]
[TR]
[TD]Silicone Rubber Diffuser Hose
[/TD]
[/TR]
[TR]
[TD="bgcolor: #339966"]

[/TD]
[/TR]
[TR]
[TD][/TD]
[/TR]
[TR]
[TD]

Application:

• Aquaculture aeration

Features and Benefits:

• Durable, lightweight, resilient silicone rubber
• Resistant to low/high pH, corrosion, crack or burst
• Light to moderate ozone resistance
• Easy to install, reshape, reposition, remove and storage
• Can be laid to form variety of patterns, allowing high coverage area with
  long hose length
• Designed for even distribution of air bubbles along the entire hose
  length
• High oxygen transfer
• Resistant to clog and with self cleaning ability
• Low pressure loss
• Low air pump power requirement
• Suitable for intermittent or continuous duty application
• Back flow resistant
• Offer years of durable and clog free service compare to traditional black
  rubber hose

Specification:

Hose size: 11mm ID, 14mm OD
Minimum curve radius: ~8 cm, ~3
in
Applicable length: 0.1 ~ 30+ meter, 4 in ~ 100+ ft
​

Example:

​

General Installation Guide[/TD]
[/TR]
[/TABLE]

Click to expand...

I have had one for over a year and these do not clog, the membrain is rubber and inflates when you put air to it. When you shut it off it shrinks back to origanal size. I bought another about 6 months ago and love them. I found a place that amkes them and they sell for $16 each I will be replacing all my stones with this. See my next post.

Well did some research into air stones and was not to happy with what I found. The blue stones, I still use them but am phasing them out, are the worst to use due to the bubble size they produce.

First thing is the smaller the bubble the better, the blue one have 5000+ micron bubbles but as soon as they get dirty/cloged they can go to 8000 to 10000 microns. The oxygen shields are 3000 microns which is great...

http://www.deepwaterinnovations.com/Products/OxygenShieldAirDiffuser.aspx

The Disk I use comes in 2 hole sizes, small and med., I use the small as the bubbles it produces are .500 microns and way better for roots.

http://www.pollardwater.com/pages_product/WED01691EDIFlexAirDiskDiffuser.asp

I'm glad to see this thread re-surfacing. Again, I feel there is a trade off between really small bubbles..like the REALLY expensive micro pore stones that offer too much resistance to flow (IMO) and the cheap ass blue stones that clog

I'm ditching the blue stones for sure. I have been looking at the alita stones which I have heard can NOT clog, ever, period, and the disks. What is nice about the discs and the alita airtones as they come with 1/2 threaded fittings so you can hard pipe them into your tank for much greater flow of air.

How do those discs work for you? Are the bubbles small enough? Looking at their website and info, my 110 lpm pump will be able to drive 4 of them at slightly above their design flow but still WAY below their maximum. They do seem like more bang for the buck compared to the DWI oxygen shield.. which seems like something thrown together to sell to growers.

AT any rate, a significant investment but may be worth while.

The reason I still like the 4" blue stones is I feel like the extra water turbulence I notice over other stones will help penetrate a thick root system. Legit concern or just retarded over-analyzing?

mike91sr said:

The reason I still like the 4" blue stones is I feel like the extra water turbulence I notice over other stones will help penetrate a thick root system. Legit concern or just retarded over-analyzing?

Click to expand...

We would need to compair apples to apples, you also need a air pump that can push the stone. The more air the better, the more air (smaller bubbles) the better.

If you want to max your blue stone use an "o"ring on each end to keep it off the bottom.

http://www.fishfarmsupply.ca/mm5/me...e=FFS&Product_Code=DB10&Category_Code=airDiff

now if your compairing the 4" blue stone to the 9" FlexAir stay on the porch with the little dogs.

I'm voteing with my money 9" FlexAir is the dope

I wasn't comparing to a stone that costs 20x as much, no. I was comparing to the other common stones on the same pump, though not specifically that one. Even still, I stand by the fact that, on the same pump, it won't be any better. Legally's test proved that 2x6" is worse than 1x6". So on a pump realistically sized for most setups, same problem with your stone. Unless I wanted to use my 112w commercial pump to only run one or two stones instead of the 12 I need, then I could just buy 5 more pumps and obviously that means more air too, but that doesn't always mean it's an efficient or viable option.

Great thread Legallyflying!

I personally would love to see some testing done to see how H2O2 (hydrogen peroxide) effect the DO levels in water. I myself grow in DWC and use 3ml of 29% H2O2 in every gallon of water that goes into my entire grow. I have always wondered the effects this has on the actual DO levels as well as how long the H2O2 actually keeps the DO levels elevated before it evaporates off. Maybe you could do some H2O2 testing.

I don't mess with pumps, I just buy big ones, 180 and 280 watt linear air pumps. I even run a 180 for my cloner and it will drive 8 6" air stones no problem. I use to run 6 or 8 small pumps but it was a pain for me.

If your comparing blue stones to ceramic or high density stones blue are at the bottom. Don't get me wrong they work good but I am always trying to get a little more out of my grows so I do a lot of testing.

Legal has done a great job, I'm just adding my 2 cents worth.

Peace

The way to get higher sustained DO is lots of small bubbles and lower temps, 62 degrees.

mike91sr said:

I wasn't comparing to a stone that costs 20x as much, no. I was comparing to the other common stones on the same pump, though not specifically that one. Even still, I stand by the fact that, on the same pump, it won't be any better. Legally's test proved that 2x6" is worse than 1x6". So on a pump realistically sized for most setups, same problem with your stone. Unless I wanted to use my 112w commercial pump to only run one or two stones instead of the 12 I need, then I could just buy 5 more pumps and obviously that means more air too, but that doesn't always mean it's an efficient or viable option.

Click to expand...

I don't agree, if you take a 1" blue and a 1" ceramic on the same pump it will out perform the blue hands down. The size of the bubbles and quantity of bubbles is far better with the ceramic than the blue. IMHO

Just put the 2 side by side and you will see a difference.

The issue is more about money than anything else in my opinion, most people who grow are just cheap, there is no tomorrow for them. I see it all the time in the hydro stores when people come in and buy the least expensive equipment. Yes some can't afford to spend much, but most don't want to. As I have always said you can buy the hay before the cow eats it or after.

I am always looking for a better way, that's how progress is made, also by failing you learn and make progress LOL

Just want to point out you want to size the air stone on the finished size of root system. As the roots grow you need more and more bubbles to do the same job, here is some more info

Injury from low (or no) oxygen in the root zone can take several forms and these will differ in severity between plant types. Often the first sign of inadequate oxygen supply to the roots is wilting of the plant under warm conditions and high light levels. Insufficient oxygen reduces the permeability of the roots to water and there will be an accumulation of toxins, so that both water and minerals are not absorbed in sufficient amounts to support plant growth. This wilting is accompanied by slower rates of photosynthesis and carbohydrate transfer, so that over time, plant growth is reduced and yields are affected. If oxygen starvation continues, mineral deficiencies will begin to show, roots die back and plants will become stunted. If the lack of oxygen continues in the root zone, plants produce a stress hormone - ethylene, which accumulates in the roots and causes collapse of the root cells, at this stage pathogens such as pythium can easily take hold and destroy the plant.

While an air pump tube alone can bubble air into a nutrient solution, oxygenation or the process of getting atmospheric oxygen dissolved into the liquid nutrient, is much more effective where many tiny bubbles of air are created, rather than a slow stream of larger bubbles. The greater the surface contact between the air bubbles and the nutrient, the more oxygen will diffuse into the nutrient solution and smaller bubbles create a far greater surface area than a few larger bubbles will. The further the bubbles have to travel to reach the surface of the nutrient, the more time oxygen has to diffuse into the liquid and the higher the rates of dissolved oxygen than can be obtained from an air pump and stone set up.

Oxygen and Temperature Effects - Effective Aeration

While forcing air bubbles deep down into the nutrient reservoir generally increases the dissolved oxygen levels in the nutrient, there is one other major factor to consider and that's the temperature of the air being pumped into the nutrient. As the temperature of a nutrient solution increases, its ability to hold dissolved oxygen decreases. So a cool nutrient solution may in fact hold twice as much oxygen at 'saturation level' than a warm solution. For example a nutrient solution at 45 F can hold around 12ppm of dissolved oxygen at 'saturation', (meaning it is the most it can hold), but the same nutrient solution at a temperature of 85 F will hold less than 7ppm at saturation. This means at a solution temperature of 85F there is much less dissolved oxygen available for the plant’s root system to take up. To complicate matters further, the requirement of the plant’s root system for oxygen at warmer temperatures, is many times greater than at cooler temperatures due to the increased rate of root respiration. So warm nutrients mean a very high oxygen requirement from the plant’s roots, but the nutrient can only hold very limited amounts of dissolved oxygen at saturation, no matter how much air is being bubbled into the solution. Ideally, nutrient solution temperatures for most plants should be run lower than the overall air temperature - this has many beneficial effects on plant growth and development. However, if overly warm air from the growing environment is pumped into an otherwise cool nutrient solution, the warm air will rapidly increase the temperature of the nutrient to that of the growing environment. If air is being pumped via an air machine with an intake close to lights or other heat sources then rapid heating of the nutrient will occur. On the other hand, cool air has the ability to reduce the temperature of the nutrient if sufficient levels are pumped in and thus result in a much more highly oxygenated solution for the plant’s roots. If keeping the nutrient solution temperature down seems to be a continual problem, checking the air inlet temperature of an air pump is a good idea. Overly warm nutrient solutions (ideally nutrient solutions should remain below 65 - 75 F) for most warm season, high light plants and well below 69 F for cool season.can have serious effects on the plants root system. Apart from the increased oxygen requirement due to a much higher rate of root respiration which can rapidly result in oxygen starvation, high solution temperatures favour many of the root disease pathogens. Plant roots become highly 'stressed' when experiencing high temperatures, particularly if there is a large mis-match between the air the root temperature. Root stress slows the development of new roots, resulting in reserves inside the root tissue being `burned up’ during respiration faster than they are accumulated, and stress makes the root system in general more susceptible to disease attack. Keeping a check on nutrient temperature is vital, as is ensuring that air machines are not blasting hot air into the solution and cooking plant roots. Aeration is most effective when cool air is bubbled into a nutrient.

Oxygenation and Nutrient Uptake

Healthy roots supplied with sufficient oxygen are able to absorb nutrient ions selectively from the surrounding solution as required. The metabolic energy which is required to drive this nutrient uptake process is obtained from root respiration using oxygen. In fact there can be a net loss of nutrient ions from a plant’s root system when suffering from a lack of oxygen (anaerobic conditions). Without sufficient oxygen in the root zone, plants are unable to take up mineral nutrients in the concentrations required for maximum growth and development. Maintain maximum levels of dissolved oxygen boosts nutrient uptake by ensuring healthy roots have the energy required to rapidly take up and transport water and mineral ions. Calcium is one important nutrient ion which has been shown to benefit from high levels of oxygenation in the hydroponic nutrient solution Calcium, unlike the other major nutrients is absorbed mostly by the root growing tips (root apex). The root apex has a large energy requirement for new cell production and growth and is therefore vulnerable to oxygen stress If root tips begin to suffer from a lack of oxygen, a shortage of calcium in the shoot will occur. This shortage of calcium makes the development of calcium disorders such as tip burn and blossom end rot of fruit more likely and severe under oxygen starvation conditions. High levels of oxygenation ensure healthy root tips are able to take the levels of calcium required for new tissue growth and development.

Conclusion

While providing oxygenation with the use of air pumps and stones is an excellent method of increasing the dissolved oxygen (DO) levels in a nutrient solution, the temperature of the air intake and nutrient solution must also be managed to ensure oxygen starvation in the root zone does not occur. Pumping hot air into a nutrient not only creates temperature stress in the root zone, it also results in less oxygen carrying capacity in the solution itself - a recipe for root suffocation that will rapidly affect the top portion of the plant as well. Getting oxygenation right means checking both aeration capacity of the equipment being chosen and temperatures in the nutrient and root zone.

I'm with woodsman on this one and I am going to order 8 of the 9" flex diffusers. I have the two 110 watts air pump that put out 110 lpm (3.8 cfm)

Because the discs have 1/2" inlets and they have data on the performance of the discs and usable air pressures etc. I am really really thinking about buying a proper commercial air pump, not these silly ass super hot mini compressors. I'm thinking about this one: http://www.ebay.com/itm/Thomson-120...?pt=BI_Pumps&hash=item1c22cc759b#ht_644wt_922


For the cost of a small pump I can get quiet, cool air and three times the volume.
I can run a hard line to each disc with a simple grommet through the grow bucket. It seems that it will have enough pressure an these are the types Of pumps that sewage treatment plants etc use to power their air diffusers. I just need to run the pressure and flow loss calculation.

Woodsman.. What you think of that thing? I just hate that airline is so damn small

Never seen them before, looks intresting.....

woodsmaneh! said:

I don't agree, if you take a 1" blue and a 1" ceramic on the same pump it will out perform the blue hands down. The size of the bubbles and quantity of bubbles is far better with the ceramic than the blue. IMHO

Just put the 2 side by side and you will see a difference.

The issue is more about money than anything else in my opinion, most people who grow are just cheap, there is no tomorrow for them. I see it all the time in the hydro stores when people come in and buy the least expensive equipment. Yes some can't afford to spend much, but most don't want to. As I have always said you can buy the hay before the cow eats it or after.

I am always looking for a better way, that's how progress is made, also by failing you learn and make progress LOL

Click to expand...

I couldn't agree more about avoiding cheap purchases. I buy quality whenever I can, though I have to admit cutting a few corners here and there. I don't think this discussion/write-up really concerns the people who are buying the cheapest shit they can get down at the local hydro shop without thinking twice, it's more for people who are trying to improve their systems or design an efficient one in the first place.

So while I'm not trying to be a cheap-ass, there has to be a substantial improvement to justify numerous stones of this cost. With a waterfarm 8 pack and 2 dwc buckets, Id be spending over $200 on air stones as opposed to $10. To see any real improvement, I'd also have to buy a larger air pump. I currently run a 110l/min, so upgrading isn't the cheapest thing in the world. The pump legallyflying linked is almost $200, totaling nearly $400 with stones to upgrade. Or I buy twice as many cheap blue stones to handle the extra air, and only spend $220. And I still have a hard time believing any noticeable difference will be seen provided they're both on this same pump.

Again, I totally agree with using high quality products, but only if they're justified. And this test did nothing but prove that the investment is better spent on a larger pump than air stones.

Lastly, great article you posted. I didn't really think about air temps that way before. My commercial pump runs hot as fuck so I'm thinking of relocating it to the outside of my tent into the air conditioned room. At least that way it will be pulling air thats in the 60s as opposed to mid-70s

^^^^
My commercial pump also ran hot so hot I couldn't touch it, now I've dedicated a fan blowing over it 24/7, that's taken care of the excess heat and provides fresh cool air for the system.