Backyard Aquaponics
A place to discuss aquaponics

I became interested in aquaponics for many reasons. One being the ability to provide more than veggies for the family. I knew tilapia required warmer water temps than nature allows for in Alabama so I thought catfish would be the reasonable choice. I built a greenhouse hoping to extend the season to year around. Recently I read that the beneficial bacteria needed to grow plants required 65+ degree temp. I know there are a great deal of solar collectors used to heat water but winters here are pretty gloomy and not enough sun. In order to keep temp good will require some sort of alternative energy source. Solar is out of the question bc not financially feasible, biomass seems good but greenhouse that I built doesn't have enough space. Extremely tight insulation could work but I have already sunk a fortune in my system. Any ideas that are cost effective and proven to work would be great.......

I don't know where you got your information from....

The beneficial bacteria that provide the nitrates for plants to grow.... through the nitrification process.... can perform over a wide range of water temperatures....

65F... is 18C.... and we consistantly grow our trout... and winter veges... at temperatures well below that at times....

Indeed.. there are members whos systems sometimes often fall below 10C... 50F.... are their plants grow just fine...

Insulate your tank with whatever free stuff you can - old insulation, fridge/oven polystyrene packaging, etc.
Then if you do have a sunny day, run the water to irrigation pipes on your roof, if not a sunny day, redirect through your compost heap (prefferably a mulch pile as there is more breaking down to be done, therefore more heat).
Thats the cheapest heating i can think of, someone else might know something better.
My friend is building an old oil burner for heating his swimming pool, maybe something like that could help you (thermostatically controlled of coarse).

This is the one he is making - It used vegetable oil.




I think this one looks easier and potentially better - although more wasteful for potentially less heat - unfortunetaly uses motor oil, maybe with more heat you could also use vegetable oil (?)

From different site:
Managing Water Temperature

Water temperature also has a dramatic effect on the speed of cycling. Their optimal temperature is between 77-86° F (25-30°C). At 64°F (18°C) their growth rates is decreased by 50%. At 46-50°F (8-10 °C) it decreases by 75%, and stops all together at 39°F (4°C). It will die off at or below 32°F (0°C) and at or above 120°F (49°C).

I have also read this on other sites. And also from University Journal pdf.

Those numbers are correct.
I think Rup jumps too quickly and often forgets people dont have his knowledge.
It did look like you were saying they need 18c to live though.

Yeah I wouldn't stress about things... Plenty of systems with low water temps have produced really well..

My FT temps get down to approx 6 deg C during winter and although everything slows, I still get bumper crops of lettuce, peas, beans, silverbeet, carrots, leaks, chives etc etc.

Just to get things sidetracked I have to ask.. Yavimaya, unusual name, you don't play magic do you?

I used to as a teenager, im a nerd
stole the name from there and been using it for the last 13 years or so.

Cool... I still play, play most weeks with a group of friends, have done for about 15 years or more.. Of course I'm not a nerd at all...

HAHAAH not a nerd.
man thats so cool, how old are you?

Too old.... 44. And the other guys I play with are both 43..

Your seriously my new hero!
AP expert and still plays magic!

If you want a waste oil heater, here you go. http://spicrosoft.com/Heater/Heater1.htm

Yeah, I read the initial post as someone having said that the bacteria required above 64 (18).. for plant growth...

Certainly when cycling.. the optimal range is 18-25 (64-77)... but that's primarily for the nitrosomonas initial conversion of ammonia to nitrite...

Nitrosomonas are relatively slow growing... taking days to double in population...

But Nitrobacter... or more correctly... Nitrospira... can double their population in hours.... and have a much wider temperature range.. effectively 0-35....

That's why you see a rapid conversion of nitrites to nitrates... and cycling completion.... essentially regardless of the temperatures.... but not before the temperature related ammonia to nitrite conversion...

The nitrite to nitrate conversion... is inhibited by ammonia... and wont begin until ammonia is effectively zero....

The lower the temperature... the slower the growth of the Nitrosomonas... the longer the cycling...

But your plants can/will still grow through out... just give them a dash of Seasol.. during the cycling period...