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Why is my compost tea getting so hot?  RSS feed

 
Jacoby Jones
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Hello, I invested in a better compost tea system for this years garden and I'm having some troubles with it. First off the system is a 20 gallon trash can and I am using a 1450 gph savio flow through pond pump. So I can put my compost tea ingredients directly into suspension without risking anaerobic condition's with a paint strainer bag. I have the pump rigged with 1 inch pvc pipes going back into the brew. Its aerated with a venturi. Now the issue is I take the temperature of the tea and the temps are increasing way too high!

I was heating it with an aquarium heater but ended up removing it to see if that would help and it hasn't. I took the temperature of the tea today and it was at 90 degrees farenheit up from 80 degrees farenheit from yesterday. This is without any other external heat source. The air temp in Ohio is around 60 degrees right now so I know its not weather. I also keep it in a cool shaded garage while brewing. From my understanding compost tea should be around 75 degrees and Im very concerned that 90 degrees is harming more of the micro-herd.

So after all that my question is do you knowledgeable people think this is caused by excess heat coming from the pump itself? Or if this heat is caused by bacterial action? Is 90 degree temps even worthy of beig concerned with?

Thanks to all on this forum.
 
Zach Muller
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Location: NE Oklahoma zone 7a
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I have brewed tea outdoors when the weather was over 100 degrees F. The brewer would even receive some afternoon sun on occasion. When i checked the microbe population with a microscope they were still doing just fine. But the heat changed my ingredients and brew time because of the different oxygen levels.

The main issue i can see with a warmer brew temp is hotter water does not have as high a capacity to hold dissolved oxygen. Depending on the timing of your temperature fluxuations, say your initial growth explosion of microbes happened in 6 hours at starting temp. If the water heats up at that point the o2 level will drop and the fluid will no longer be able to keep your microherd alive. Use your nose on this, by taking nice long sniffs over the brew. Once most things are dead and the o2 is too low for aerobic microbes the stench will set in, a good brew pretty much never smells funky or sour. Once it dies it will only take a matter of hours to smell bad.

I would guess the heat is coming from the pump and not the microbe action, with an ambient temp of 60 i would expect a brew to be closer to that temp give or take a little, not 30 degrees off.

A pump that creates heat in the water is not ideal, but you can adjust your levels and still brew some good stuff. If you add less compost and less fuel than you might end up with a perfectly fine brew still, just play with the amounts and keep smelling.
 
Peter Ellis
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Location: Central New Jersey
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You have a 20 gallon tea barrel? and a pump that can cycle that barrel more than once per minute?

Pretty sure that pump is much, much larger than what you need for the job and yeah, with it being that overpowered, it may well be heating your water.
 
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