Aquaponic Gardening

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I'm in the design/building/gathering parts phase of my construction. I am trying to get it right the first time. I'm not a fan of trial and error.

I dont have any grow beds yet and the greenhouse may be another year away.

Right now i'm working on the fish tanks, and i want them to be the best fish tanks ever. I have designed and built air powered water circulators that will create a constant current and aerate the water in my 5 IBC totes. These cost about $25 bucks each to built, But i believe they will make the fish much happier and healthier in the long run, and at this point its all about the fish. Later on when its time to build the grow beds, it will be all about the plants.

OK as of right now i have 5 air lines going to my tanks, I'm using 1/4 plastic line with a stainless steel threaded insert to inject the air into the circulators, because the water will be touching the fitting i am using stainless steel. These cost $12 bucks each. Don't get me wrong im not complaining about the money. Like i said before, Its all about the fish at this point. If i have to buy 50 more fittings, I will. But i'm trying to spend the money where it is needed.

My question is how do i know if i have enough air? Is their a test that i can do to measure the air content of my water? Is their a tester that i can buy to do this. I'm sure my fish load will change and thus my oxygen requirments will vary as well. How can i measure oxygen need?


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There are tests you can run to check dissolved oxygen content.  My experience is that the chemical tests are kinda a pain to run though since it involves many steps with some dangerous materials.

There are also dissolved oxygen meters.  They tend to be expensive but if you really want to monitor your dissolved oxygen levels, they are probably your best bet.  I've so far done fairly well by paying close attention to the fish and their habits but I don't have any numbers to go with my observations.  Granted, the dissolved oxygen meter is only going to be as good as it's use and maintenance.  If you get a portable meter it will only tell you the levels when you actually run the test.  If you get one of those systems that monitors the levels constantly, you may need to be replacing the probes on a regular basis but I think some of those fancy aquarium systems might actually have alarms that could notify you if something is going wrong.

Thanks for the info guys. In addition to the 5 IBC, i will be running 5 = 10 gallon bio-filters, 5 = 29 gallon breeder tanks, and a 29 gallon hospital tank. all of which will have an air stone. I'm building my water manifold now and will start on the air manifold soon. As of right now i have 16 points that air will be injected, I'm sure that is plenty of points. I know i will have more by the time my system is complete. I can adjust the air volume at each of these points to balance O2 requirements and compressor run times.

I have a lab at work that can check my DO, Free Chlorine, ORP, Ammonia, Nitrite, Nitrate, and Biological activity, I plan on using them as a double check about once a month to confirm my test results. I wish i could use them daily but that isn't possible.

Im looking at buying a tank wall like you would see at Walmart to complete my fish room. This wall contains 5 = 30 gallon tanks divided into 3 = 10 gallon tanks each. All mounted on a steel frame.

It is my intention to start out raising blugill and catfish to eat, Then as my system comes together, expand into breeding and raising oscars and feeder fish for the aquarium industry.

This is a great hobby.

I use PVC venturi pipes in the water returns from the grow boxes.  If you want the plans for the venturi send me an email.  phil 

As for fish, I just got off of a hour phone call about raising fish with one of the very well known people in Aqua farming.  His idea, develop micro farms for fish of interest to the Asian market.  No long shipping, they are sold within 25 miles of the farm.

My cpa/attorney, god bless him, has has a grant writer now on staff and between the two have all the info on government grants for fish farmers.  Perhaps Tilapia, chinese carp and eels are in my future and not catfish.

Best, phil

Phil, That is a wonderful idea. Make some cash while enjoying aquaponics. Good luck.

Ok, So sent alot of time on the internet last night and learned quite a bit about dissolved oxygen and the test procedure. You can go a couple different directions with it. #1 Buy a relatively expensive probe and follow the instructions for its use. #2 Buy a relatively in-expensive test kit that has some dangerous chemicals in it. Both would give you very accurate results. #3 have a lab test your water.

All of these options have advantages and disadvantages.

Like i said, I spent alot of time searching and found the above options, Then i spent alot of time thinking about the problem. How can I figure out if i have enough air in my system? Well i looked at what effects dissolved oxygen, and came up with temperature, altitude, pressure, biological loading.

My idea is to measure DO using a vaccum gauge to lower the pressure of the water sample to a point of boiling at room temperature and recording the (in Hg vac).  This method would have to be done at a point when you know you have a good DO level to get a baseline. Then this procedure can be repeated later as a problem solving tool to compare current (in Hg vac) to the baseline. It will tell you if your DO levels have dropped from the baseline.

The thought behind it is, The less DO in the sample, the more vaccum it will take to start boiling

Problem solved??  Now in off to the parts store to buy a vaccum hand pump.

Tony, there is one flaw to your vacuum measurement idea, and that is just because your water is depleted of oxygen, doesn't necessarily mean it is deplete of all dissolved gas.  Quite the opposite, water that is really low in DO might have high levels of dissolved CO2 and I expect that could really mess with your testing by vacuum method.

Well i never thought of that. Thanks TCLynx. See thats why i put in on here, to get other peoples thoughts. There goes my million dollar idea right out the window. LOL Guess i will have to think about it some more. Thanks

If you provide some form of ample extra aeration and you are going with reasonable hobby/backyard type stocking densities, then I would say you can probably manage by careful observation.

If you are planning somewhat high stocking rates and going with say Trout, then perhaps the DO monitoring could be worth while.  Some of those aquarium automation rigs I think can monitor DO as well as pH and control pumps or lights etc and might be worth looking into or an actual DO meter.  Otherwise a test kit that you pull out on occasion might help your piece of mind.  To tell the truth though it sounds like you will have plenty of aeration since you are using air to circulate water.  How important is it to you to know the number when careful observations of your fish will probably tell you about a problem (and you are likely to immediately see that oh the circuit tripped or the airline came undone or whatever and fix it before you ever go get the tester or test kit and run the test.)  So unless you are planning insane high stocking (in which case you probably want something that can set off an alarm and phone you that there is a problem since it would be rare to wander by and preform a test by chance when a low DO incident is in progress) I don't know that testing will help you that much.

DO seems to be the most limiting factor in AP. I just want to be able to stock the tanks to a maxium SAFE level and not go way overboard. Here is a pic of my fish room alot of aquariums aren't installed in this pic.

Well there is a lot involved in figuring out aeration and the definition of "maximum safe stocking level" is going to play a bit roll in it as is the type of filtration and plant growing.

Dissolved oxygen becomes more limiting at high temperatures and heavy Biological Oxygen Demand.  If you are removing solids, then your biological oxygen demand will be lower and the need for extreme aeration becomes less.  Flood and drain aquaponics or trickle filters have the benefit that you don't need to provide aeration for your filtration (since they essentially are aerated by their trickling or draining nature, only supplemental aeration for the fish tanks.  If you are using other means of filtration, you will need to provide some form of aeration for your filters as well as the .  And DWC or raft type growing options also require extra aeration.

So I don't know that I would say dissolved oxygen is THE limiting factor, it will really depend on the design and the situation.  It all works together as a whole.  If you don't have any filtation, I don't care how much oxygen you have dissolved into the water, the fish and plants won't thrive (probably won't even survive.)  If you don't have any fish or source of nutrients, then the filter and plants won't thrive with just dissolved oxygen and water.  If you don't have any plants, you then wind up needing to change out water because an overabundance of nutrients.  And if you don't have any water then none of it works despite the overabundance of aeration and oxygen.

TCLynx, This pic is of my fish room. They will drain through a 3 " pipe through 200' of dirt (free heat and cooling), to my 20'X40' greenhouse with 2 = 4'W X 38'L flood and drain grow beds. The grow beds will drain to a 4'W X 30'L raft bed that will drain to a 10' deep sump and return to the fish tanks.

All of this is yet to be built except the fish room and the greenhouse. The greenhouse has a bare frame and 30 tons of stone spread inside, But right now im spending my time and money on the fish room, I want to make it the best fish room ever.

This is going to be my hobby when i retire in a few years, So i want to get started now.

I am trying to get it right the first time.

I think i am going to have plenty of DO going into the system, I just wish i could measure it without spending $$$ Or dealing with harsh chemicals that my grandkids could get into.

I thank you for your help with this project

I guess the best way to deal with it is to install alot of points of areation and tweek them as i go


Who manufactured your greenhouse and where did you get it?  Thanks!


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