Trough aeration increases plant growth!!

[Chris Smith]

I have seen several aquaponic farms in the area that have been adding supplemental aeration in their troughs and getting dramatic increases in plant growth in the immediate area of the aeration. Seeing this happen has prompted me to add aeration to my troughs. I just got done running main lines with a blubber every 4 feet in my troughs. I hope to increase my plant growth with the extra DO.

I plan to add an air stone every 2 square feet in my micro system as experiment to compare to the commercial system.

My current theory and direction are going toward a low water transfer of about 2 gpm through the troughs and high aeration. I will down size on the water pumps and add to the air pumping capacity. My electricity costs $.44 kw hr so I want to get the systems as efficient as possible.

 

 

[Mel Soule]

Mel Soule said:

Sahib Punjabi said:

Hello Michelle,

 

I just have three of the following outdoor Air Pumps purchased from Aquaticecosystems (50w 3/8 barb). For the DWC system, I share one pump with the Gravel systems - here I have 2 12 inch Sweetwater Air Stones in the 1,000 Gal Koi Pond. On another Air Pump, I have 1 12 inch in the second 55 gal barrel and have added about  6 3 inch air stones every 6 feet in addition to the 10 1 inch air stones that were there before.

 

My next task is to further increase the aeration be sharing the third Air Pump between the Catfish IBC 285 gal IBC tote - one additional 6 inch Air Stone and take a split line for another 5 to 6 3 inch Air Stones in the 48ft DWC bed. That g=should be plenty of air...I think.

 

I do not have a DO meter yet so can not share DO level info. I just look at plant growth rates, quality of water and condition of fish to know that they really do love the extra aeration :-)

 

God bless

Michelle Silva said:

Sahib, can you give some details on what you added in terms of quantities of size of air stones, distance apart, etc. I'm thinking that I would like some more aeration..I added three gravel beds and have some additional splashing into the sides of one of the raft tanks, but I think I could use a lot more. Do you happen to know what your DO levels are?

Hi Sahib,  you note your pumps are 50 watt.  Are they rated at 3600 cu.in/min?

Also what kind of tubing are you using to each airstone soft wall tubing or rigid wall tubing?

Thanks

Mel

[Harold Sukhbir]

Aeration,temperature of the nutrient solution and ample light are important factors for any crop grown in raft.We try to keep these in their optimum range for best growth. Found this on the net and even though it's a study done with Hydroponic culture it contains some important facts we can translate to AP.

 

 

[Sahib Punjabi]

Thanks Sukhbir Sir...very good info to consider and incorporate in AP systems :-)

[Mel Soule]

Great summary article Harold.  Thank you.

 

Sahib, I don't know if you saw my questions above.  I messed up my composition of the post trying to refer to your, so my comment is buried.  Here they are again:

 

 Sahib, you note your pumps are 50 watt.  Are they rated at 3600 cu.in/min?

Also what kind of tubing are you using to each airstone soft wall tubing or rigid wall tubing?

I ask about the wall type on the tubing only because in another life, at university when I managed the Biology Dept. fish tank lab, we found the rigid wall better at reducing pressure drop from the manifold to the dispersing stone. 

Thanks

Mel

 

[Harold Sukhbir]

Lot of salient points in the study. Notice the results of growth rates on inline spacing vs staggered spacing. I believe the inline spacing offers channels for aerated water flow while staggered allows restricted flow and keeps aerated water increasingly at the bottom of the root system as the plants grow. So to get better growth and avoid anaerobic conditions in using staggered spacings, we will have to, as a matter of course, to in-cooperate supplemental aeration. 

Sahib Punjabi said:

Thanks Sukhbir Sir...very good info to consider and incorporate in AP systems :-)

[Mel Soule]

The important information about D/O in inline vs staggered is not visible to me.  The author notes a general D/O recommendation but does not correlate that to the inline vs staggered growth results..  Their grow tank appears to have an aeration trunk line running down the center of the tank with outlets at every 3.5 meters over the 70 meter length.  I would like to have seen D/O on the growth medium inlet end of growth tank and the D/O at the return to the growth medium reservoir.  I would also like to have seen the colder water temperature growth results of the inline versus staggered runs.  I'm assuming they draw the conclusion of reduced growth/head with the only independent variable being inline vs staggered plant spacing.

 

Harold, I do not yet have a system built and running but have been trying to learn as much as possible but I wondered when I read their grow tank dimensions at 30cm depth.  that seemed deep for plants.  Is that 30 cm depth a traditional design number?

[Sahib Punjabi]

Hello Mel,

I cannot find much details on the web and I believe that this is a "special" air pump made for Aquatic Eco-Systems. I have scanned the psi/cfm info so you can see the efficiency and perhaps fill me in too :-)

 

Mel Soule said:

Great summary article Harold.  Thank you.

 

Sahib, I don't know if you saw my questions above.  I messed up my composition of the post trying to refer to your, so my comment is buried.  Here they are again:

 

 

 Sahib, you note your pumps are 50 watt.  Are they rated at 3600 cu.in/min?

Also what kind of tubing are you using to each airstone soft wall tubing or rigid wall tubing?

I ask about the wall type on the tubing only because in another life, at university when I managed the Biology Dept. fish tank lab, we found the rigid wall better at reducing pressure drop from the manifold to the dispersing stone. 

Thanks

Mel

 

 

[Harold Sukhbir]

Hi Mel,
Yes i agree their was no clarification in the study on reasons for growth rates between inline and staggered. Hoping we can uncover a subsequent study to explain and in the meantime open this up for discussion here or in the group. The only variables i can see are flow rate and or DO levels.

On the question of trough depth, most hydroponic studies I've seen are done with this 12 inch marker depth, and Friendly Aquaponic recommends this in AP as well. I see that the minimum of both media beds and troughs in AP is the suggested 12 inch standard depth.

Hope you decide to initiate your raft system soon and i know there are many highly experienced Rafters in your group always ready to discuss issues if they should arise. I've been running a raft for the past 4 weeks, the growth is amazing, and it's loads of fun.

[Sahib Punjabi]

?...

Sahib Punjabi said:

Hello Mel,

I cannot find much details on the web and I believe that this is a "special" air pump made for Aquatic Eco-Systems. I have scanned the psi/cfm info so you can see the efficiency and perhaps fill me in too :-)

 

Mel Soule said:

Great summary article Harold.  Thank you.

 

Sahib, I don't know if you saw my questions above.  I messed up my composition of the post trying to refer to your, so my comment is buried.  Here they are again:

 

 

 Sahib, you note your pumps are 50 watt.  Are they rated at 3600 cu.in/min?

Also what kind of tubing are you using to each airstone soft wall tubing or rigid wall tubing?

I ask about the wall type on the tubing only because in another life, at university when I managed the Biology Dept. fish tank lab, we found the rigid wall better at reducing pressure drop from the manifold to the dispersing stone. 

Thanks

Mel

 

 

[Chris Smith]

I visited a friends farm today where I saw an obvious example of the effects of aeration in the trough.

This trough has 3 soaker hoses running down the length. The middle hose has clogged up and is no longer putting out bubbles. The difference in growth is very apparent.

If you look closely there are bubbles on the right and left sides but not in the middle.

[Alpine Aquaponics]

Coming from the hydro world that amount of aeration looks like practically NOTHING!  Im curious how fast his flow is, it must be reeeally slow for the DO in the water to not mix.  Im having a hard time wrapping my head around the fact that plants can be that different so close together, I've never seen anything like that

 

In my experience DO is the most important factor for speed of growth.  The return on getting more harvests would almost definitely make up for the extra cost of adding more air

 

Ideally it would be better the make the troughs shallower if the water flow is that slow, that way less air can have a greater effect.  Root space is important, but that is way more than what's needed.  The main thing to worry about is the relationship between speed of flow and depth of water - the roots cant be flyin around and entangling one another or harvesting is a problem.  You want just enough depth so the roots can hang straight down, but having plant sites that close makes it an unavoidable problem anyway I'd guess

[David Hart]

 

Wow, thanks for posting the pictures Chris. That's incredible.

Alpine AP, you made some great points....I too, would think the water flow would mix the DO some (?)  Bubbles, themselves 'normally' move/mix the water to some degree. With that many roots, they must prevent the 'mixing' of the water.