10 min $10 DIY aerated compost tea ACT brewer

[Microbeman]

Bonsai; Nice, I'm working on a system employing a bulkead for 12 gallons. I'm shooting for something cheap that we can sell cheap and I found a source of inexpensive recycled tanks. I'm thinking of trying one design with the bulkhead out the side, eliminating the need for a stand. It won't be vortex but should work fine. I'm just concerned about potential compost sitting on the flat bottom. Are you getting this with your design?

 

[bonsai]

tuinman: thanks for the tip! Fingers crossed I can fix it.

Microbeman: The top of the bulkhead is about 10mm high, and as a result I do get 10mm of undrained remnants after use. The type I've got couldn't be used on the side as it's a 30mm hole with a 120mm rubber grommet on each side. The 10mm dead sapce is a compromise I was willing to make due to the prohibitive expensive of sourcing a cone-bottom tank in Australia.

 

[LesterBangs]

Wow, this i got to try!
It would upgrade my teas alot!

 

[Bullfrog44]

Threw some stickers on my brewer that I got from the hydro show. Now my brewer is pimped out. Probably wont last long because of frequent washing, but o well.

 

[tuinman]

Welp, I've spent a good chunk of the afternoon getting a vortex going in a 10g square cone tank - I would say it's not worth the effort. I am able to get a small one sustained but it only goes down a few inches.

 

[Bullfrog44]

I believe that a small vortex is better than none at all. Especially if you are breaking the surface of the water with the air lift still. It just adds surface area and sucks in air. Not sure if I am right about this or not, just my two cents.

 

[Microbeman]

I remain unconvinced about the importance of creating a vortex. The people who are really into the whole vortex thing, I believe, contend that there are some almost magical qualities imparted to the water via the vortex but I have yet to see concrete evidence of this. Vortexes are cool to look at though and who knows what future science may reveal? As Bullfrog has mentioned, the breaking of the surface tension is more important. It is this and the unique multiplying effect an airlift has on dissolved O2 content which counts most.

 

[tuinman]

I've reverted mine back to standard, and the breaking of surface tension is improved over a vortex attempt. I was hoping to get a vortex going solely for mixing of solubles such as SP-90, which tends to collect at the bottom of the tank if not added slowly.

 

[Microbeman]

I'm not a big fan of adding humic acid to compost tea unless in very minimal amounts. In my experience humic acid can delay microbial growth and division in a liquid like compost tea and it may be better to just apply it to your soil separately. Others may have a different experience from mine so don't treat my statement as gospel. It is just that if what you are putting into a compost tea does not directly feed microbes, then I do not see the point. I think there is benefit to the root system from humic acid but adding it separately or in a nutrient mix may be the better way. What one is trying to do with aerated compost tea (ACT) is to grow out a high density of diverse microorganisms so everything you can do to preserve the appropriate O2 levels and provide the fewest foods possible to the greatest range of microbes is key. One reason black strap molasses and fish hydrolysate is so good to use is that they feed both bacteria and fungi.

 

[bonsai]

The biodynamic crowd are the ones enamored by the supposed spiritual energies of the vortex. I just like that it splashes less than regular airlift while still breaking surface tension.

 

[tuinman]

I'm not a big fan of adding humic acid to compost tea unless in very minimal amounts.

My apologizes for not being clearer - I also use this brewer as a water dechlorinator and a general mixer for nutrients. I don't add humic acid to ACTs, or really anything else except the recipes on your site.

 

[Microbeman]

My apologizes for not being clearer - I also use this brewer as a water dechlorinator and a general mixer for nutrients. I don't add humic acid to ACTs, or really anything else except the recipes on your site.

No worries, I was not sure you meant that but it needed saying again anyway. I had a call from a client back east who had been using copious amounts of humic acid in ACT on lawns because the guy selling him the humic acid recommended it.

 

[Bullfrog44]

I remain unconvinced about the importance of creating a vortex. The people who are really into the whole vortex thing, I believe, contend that there are some almost magical qualities imparted to the water via the vortex but I have yet to see concrete evidence of this. Vortexes are cool to look at though and who knows what future science may reveal? As Bullfrog has mentioned, the breaking of the surface tension is more important. It is this and the unique multiplying effect an airlift has on dissolved O2 content which counts most.

I think a couple notes about my vortex brewer that I see as an advantage:

-More air over a bigger surface area of water. If you measure the surface area of water touching air in a regular 5 gal bucket it is minimal. Add a vortex and you at least double this.

-I notice a sucking sound happening, kind of like the sound the bath tub makes. I believe this might be the same effect that breaking the surface tension of the water would give.

-It is cool looking and helps sell brewers.

Microbeman - Have you noticed a negative effect from any vortex brewers?

 

[Microbeman]

No negatives; Infact a positive is the very thorough mixing.

Of note is that your first point

More air over a bigger surface area of water. If you measure the surface area of water touching air in a regular 5 gal bucket it is minimal. Add a vortex and you at least double this.

I believe applies to any fairly fast moving airlift system.

Also of note is that you have created (according to your photos) a much more 'radical' vortex than is normally created in the commercial units (I believe). The videos I've seen show a 'dancing' vortex protruding down from the surface, while your photo shows quite a central cavity created...so yes your's would have a greater area of atmosphere to water interface.

 

[Bullfrog44]

Thanks for the response Microbeman. My vortex goes all the way to the PVC. When I add my fish product I watch as the foam disappears down the vortex hole and it goes way down. I am brewing some tea right now but I have been thinking about one of your last posts.

Nice work BF, The only thing I wonder is if there is any difference if the air input is at right angles, rather than under the Tee (riser pipe). Do you follow me? That is how I set them up. In your photo the Tee would be reversed so the air input came in from the right. I'm unsure whether this is more efficient use of air 'pressure' but that is what I found. I also found varying flows by varying the distance of the air input from the center of the riser pipe.

Are you saying turn my T so that it has the air intake parallel to the PVC feeding the T? Or are you saying replace my T with a 90 and add a T 4" up? I am not sure what you are saying but it got me thinking. Does the way I have my T make the EWC settle below the actual water level? I can see EWC make its way into my air tube, not much but still. I think both interpretations of what you said would help with this. I am thinking the best answer might be the T 4" up. Not sure if you follow, but any thoughts?

 

[Microbeman]

Thanks for the response Microbeman. My vortex goes all the way to the PVC. When I add my fish product I watch as the foam disappears down the vortex hole and it goes way down. I am brewing some tea right now but I have been thinking about one of your last posts.



Are you saying turn my T so that it has the air intake parallel to the PVC feeding the T? Or are you saying replace my T with a 90 and add a T 4" up? I am not sure what you are saying but it got me thinking. Does the way I have my T make the EWC settle below the actual water level? I can see EWC make its way into my air tube, not much but still. I think both interpretations of what you said would help with this. I am thinking the best answer might be the T 4" up. Not sure if you follow, but any thoughts?

Hi Bullfrog;

We could probably confuse ourselves 'real good' by descriptions of pipe attachments and placement of fixtures. Instead I've attached a little PDF sketch to clarify. Note that I moved the riser pipe in so as to reduce the distance the water travels from the cone to the riser pipe. Also I moved your valve for emptying so to be adjacent to the cone. This will eliminate the potential for dead water and compost to sit in this pipe while brewing. The return nozzle can be located wherever for desired flow pattern (e.g. vortex)

As I mentioned previously you can create flow velocity variances by increasing/decreasing the distance of the air input from the center of the riser pipe. I have designed a diffusion chamber for this interface which I believe further raises the dissolved oxygen (DO2) capacity of the pump used. In this way your DO2 is not so much a factor of agitation perceived but of the 'pressure, velocity and bubble size' created in the airlift [I think].

 

[DARC MIND]

why not just connect a T (side ways)under the cone and use that ball valve to empty straight dwnward and not to the side with extra (dead zone) pipe?

also the male PVC adapter can connect right to the T, on the bottom of the airlift tube
i dont see a need for that extra peace BF is using to connect the air tubing to the lift pipe

 

[Microbeman]

why not just connect a T (side ways)under the cone and use that ball valve to empty straight dwnward and not to the side with extra (dead zone) pipe?

also the male PVC adapter can connect right to the T, on the bottom of the airlift tube
i dont see a need for that extra peace BF is using to connect the air tubing to the lift pipe

Good point on the first. I cannot really see what he is using for the air interface. I use an extra fitting and length of pipe to incorporate a diffuser and set distance.

 

[Bullfrog44]

Dam, you guys make a lot of sense. I will be for sure making these adjustments. That picture really cleared things up also. The only thing I might skip is moving the riser pipe closer, just because it is as close as it can get without being on the other side of the 2x4. The 2x4 hugs the bottle and keeps it level. I check my level every brew to ensure my gallons marker is reading correct. (did I mention I was anal?) I will make the adjustments and take a picture. I won't make a brew until this weekend so I have some time to mess with it. Thanks for the help again Microbeman and Darkmind.

 

[Microbeman]

Oh ya. Considering Dark's suggestion re the valve, it may be cramped directly under your vessel so you may wish to empty to the side as you presently have it. If the lift is functioning (which it is) you don't need to relocate the riser position.