Aquaponic Gardening

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I am thinking about making a thermal wrap for my fish tank for freezing. My tank is 1/4 in HDPE and is 300 gallons. It is on my patio now and I am in Florida where we get several freezes per year.Not hard freezes but it can get down to 28-28 degrees at lowest. I have Bullhead Cats. They are pretty hardy. I haven't been through a summer with them though. Anyone have any ideas about winter/summerizing the fish tank? I understand that if it gets too hot it can cause bad bacteria to grow as well.

I have the option of moving UGGG) the fish tank indoors onto a sunroom and replumbing the growbeds to go outside. Any thought on that?


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Keep in mind that insulating the fish tank doesn't do much if you are flooding/draining your grow beds.


I'm growing channel Catfish.  I think bullheads will survive a cold snap well enough.

Important things to keep in mind are to adjust or even quit feeding when it gets too cold (I just killed a whole tank full of fish by leaving town with the automatic feeder still operational and it got cold but the feeder didn't know that.  Anyway the effective over feeding left me with a tank full of dead fish.)


How I might recommend adjusting the system during the extreme temperature swings.  Just set the system to run constant flow/flood and that will help stabilize temperature during the extremes.  Actually running the system constant flow/flood is actually a good way to get cycled up too.  In a regular timed flood/drain system this might be as simple as letting the pump run full time.  In my indexing valve system I simply removed a part from inside my indexing valve and flipped all my stand pipes upside down and let the pump run full time of course when I do that, I have to add quite a bit of water to my system to keep the fish tank level from dropping too low since it is a 300 gallon fish tank with 600 gallons worth of grow bed.  So when I put my system back to flood and drain (probably next month) I'll have to pull out some water when I go back to my normal operation.


Again, we bullheads, I expect you will be fine with an outdoor system.  Just might need to add a bit of shade for your fish tank and maybe even the grow beds if you find the water getting over 90 F too much in the summer.  My big system doesn't usually get water temps much over 86 F but I haven't had the 300 gallon system long enough to know for sure how hot that one might get through the summer.  Just run supplemental aeration when the water gets over 80 F and things will probably be ok as long as the power doesn't go out and the water temp doesn't go over 100 F.

Bullheads are one of the toughest fish out there if they are the same type as we have here in Nebraska.  Growing up on the farm we would catch Bullheads and put them in the cattle tank by the barn.  10' Galvanized tank and no aeration except when the cattle would drink!  Those things would live in there all summer.  Most of the time they came out of a pond that was probably only 2-3 feet deep and most likely froze almost solid every winter.  Running their water through your AP and aerating will make them think they are in heaven. 

Good Luck with the system.

If you can move it inside then great. If not you can get a pond heater to keep the water from getting to low. Controlled by a 

Thermo Cube.

As long as they are not tiny fingerlings when cold weather hits, catfish and bullheads can survive below freezing water.  I actually prefer to let my aquaponics have some seasonal fluctuations now days, makes it far easier to grow cool weather crops if the water temp can drop a bit.


Just want to make sure your water doesn't freeze in the pipes or anything.  Not too much danger of that here in FL with flowing water.

Thanks for the input. What do you think about the heat. Will that affect the Bull Cats? I was told at the hydroponic store where I buy supplies, that when it is too warm, bacteria can get out of control and cause alot of damage to crops.

Provide plenty of aeration, flow and filtration for your system.  Aquaponics is different than Hydroponics so not all the same rules apply.  Remember that most hydroponics systems will only have a small nutrient tank which will tend to heat up a lot more than a 300-600 gallon fish tank.  A 50 gallon barrel feeding an outdoor hydroponics set of NFT pipes will heat up badly during summer, a 300 gallon fish tank will be far more stable.  The bigger the fish tank the more stable it gets.


What sort of filtration do you have?

Gene Carr said:

Thanks for the input. What do you think about the heat. Will that affect the Bull Cats? I was told at the hydroponic store where I buy supplies, that when it is too warm, bacteria can get out of control and cause alot of damage to crops.

I'm in the middle of my third aquaponic summer, and have not have serious bacterial outbreak issues.  Because the fish metabolism and nitrification / mineralization processes will be peaking, your DO levels will come under pressure, particularly as warmer water has less of it to begin with.  You will find some cooler weather crops such as lettuce will go on strike, but others will grow right through summer.  The passion fruit vine, flat-leaved parsley and spring onions seem to be year long crops for me, strawberries are still allright, basil is hanging in there but many of the leaf crops suck. 

Gene Carr said:

Thanks for the input. What do you think about the heat. Will that affect the Bull Cats? I was told at the hydroponic store where I buy supplies, that when it is too warm, bacteria can get out of control and cause alot of damage to crops.

I am just starting my 200g AP system and I am worried about West Texas heat and the fish.   I have my system set up on the east side of my house so I can get the early light. Trees over-head may supply some shade but I am not expecting too much. Would implementing a geo-thermal water-line to my grow beds keep the water cool enough or will the temp go back up before returning to the fish tank?   Would the plants benefit with cooler water on their roots?  Should I build a soil wall around the tank to insulate or should I bury the tank in the ground?  (I would like to avoid that labor if possible) Photo in my profile is of my friends system, I am making an identical system. Thanks for any insight.



If doing flood and drain media beds, insulating the tank will have only minimal effect since flood and drain media is such a good heat exchanger between water and air.  See as the beds drain the air gets pulled down into the beds to work on adjusting the temperature of the media and then when the water flows into those beds, it tends to come closer to the air temperature.  This will be most apparent during the hottest summer afternoons/early evenings and then again during the coldest winter early mornings.

Again one way to deal is by going constant flood during the worst extremes if the water is getting too cold or too hot for the fish during that time of year.


In West Texas, you can probably get some evaporative cooling effect by making sure air can breeze across the water but this will evaporate the water more and you will need to top up more often.  Having a good plant cover over the grow beds to keep the sun off the media can also help and some shade cloth can sometimes help keep the plants from wilting in the afternoon if your sun is particularly harsh.

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