Aquaponic Gardening

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It's finally almost time... I have some plumbing to do then I can get at least one table up and running with a temporary fish tank in place till I can build my pond. Plumbing is the easy part. I really want to buy some hydroton but at 7 each 50L bags for 1 table it's going to get real expensive real quick. I'm going to visit our local hydroponic store but we're probably looking at around $30 a bag. I have a "top soil" business right up the road that I can get pea gravel real cheap. I figured I'd ask the experts first. Your feedback could definitely save me big time!!! 

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How deep are your grow beds?  They look shallow to me.  I have always thought they should be 12".  I'd skip the hydroton and use 1/2" gravel (check for limestone with the vinegar test).  Just as good as a media and so much less.  I actually use pea gravel which is working well and much nicer on the hands.  The space of the larger gravel is probably better.  I'm also thinking of taking some gravel out and mixing in red lava rock.  Don't know when I can do this as the beds are never empty.  I've also started using coral when water is pumping into the beds and where it drains back (one system drains into the sump and the bigger system drains into the fish tank).  This is helping with pH and I recommend doing it.


Linda, Thank you very much for your response!!! My decision's made... pea gravel it is. Hydroton would cost me 14 bags at $25 a bag ($350) plus tax & shipping if I can't find it around here. And shipping appeared to cost more than the hydroton. That's why I asked... Pea gravel is $27 a yard and I only need about a half a yard for both beds. Talk about a money saver!!! 

The beds are only 6 inches deep and meant for plants with a shallow root system. Many plants will be put in there for initial growth then transfered to the exterior dirt vegetable garden for continued maturity and "fruit bearing". I also have a worm ranch that provides excellent organic nutrient enriched food for optimal growth. Also, what is not seen in the picture is the left side of my greenhouse. I have 6 DWC buckets set up for tomatoes, peppers and similar plants and I plan to expand it to a recirculating 12 bucket system. I'm looking forward to sharing pictures as I progress :) 

In my pea gravel beds I have 3-4" of large (1 - 1.5 ") red lava rock on the bottom.  So make your bottom 1.5" large lava rock and then pea gravel over.  I washed all my rock first but there is some discussion about the fines giving trace elements.  Have to think about the impact on the pump.  I have some lava rock fines in sump with pump and all is ok.

The other consideration is to mix coral in the beds where the water flows in.  I think this is a really good idea or I have it in a mesh bag where my water flows into the sump.  Just want the water to be flowing through it to get the pH adjustment.  I used about 4# in my 300 gallon FT system (with sumps probably 450 gallon) and 1# in my small half barrel (50 Gallon FT) system.

Is the worm farm your business.  Be sure to add worms to your grow beds.

Thank you for the advise!!! Lava rock first, pea gravel next, along with coral in the beds where the water flows in. Got it!

I plan to do a 3 volume flush of the rock before connecting it to the tanks. That's simply done by plugging the hose and flooding the table till my medium is completely submerged, then draining it completely. This should wash the majority of the fines but still keep much of the trace elements. Also, I have it under good advice to add a bioflilter fountain to the deep end of the future pond I will be installing this spring/summer. The biofilter balls initiate the conversion of ammonia to nitrites and then into nitrates.


This is all just a hobby to me. Although I'd love to retire and do stuff like this all day I'm not even close to it. The worm farm is something I bought from Julie. She's the owner of 3 in 1 Worm Ranch: Her and her husband have been growing worms as a hobby for years, then due to supply & demand decided to make it a business. My goal is to make my system completely self sustaining... Worms feed the fish, fish feed the plants & plants clean the water. Hopefully by the end of summer 2015 I will have my potting shed built on the front of my greenhouse and solar pannels installed to run the basic pumps. All in good time :)

>.. Here's something to think about; surface area of the media. I used a mix of pea gravel (had some on hand), small bits of lava rock (old aquariums), and lots of 3/8ths gravel (without fines - so it was sifted after crushing). Lots of 3/8ths gravel, like 3 yards. I was advised that the surface area of pea gravel versus crushed gravel was much less (for the pea gravel) due to the smoothness of the surface.The beneficial bacteria, you will want, live on the surface of the media. More surface area = more space for bacteria.

>.. And at local gravel yards the cost of pea gravel was higher. I took an old pickle jar, about 1/3 full of vinegar, to the gravel yard in Port Orchard and tested the gravel. I dropped a small amount, like half the volume of vinegar, into the pickle jar. Big bubbles are just trapped air, steady stream of small bubbles = limestone. No limestone.

>.. If you bring containers with you, they will sell less than a yard but price per unit volume is higher. The best price is, of course, multiple yards of gravel, but that's not for your purpose.

>.. I have used the gravel for more than a year, getting good growth of both fish and plants. Expect cloudy water, even if you rinse the gravel yourself, for about a week after starting the pumps. Most fish can live in the cloudy water, but the chemistry won't be right for the fish until you've had bacteria converting ammonia to nitrites and on into nitrates.

>.. What kind of fish are you planning for?

From the above information I'm gathering that I don't want limestone. I will check it and confirm prior to purchase. I have a quarry right up the road and a 1 yard trailer so getting whatever I want is not an issue (except for hydroton). Whatever I want is pretty much $27 a yard across the board. I have a very large yard and plenty to do with it, so having excess is no big deal.

As mentioned before, I plan to build a pond inside the greenhouse. I'm thinking I want to expand it to allow fish to swim under the tables. It will give them some privacy when they want it and allow for a bigger pond and more fish. It will specifically be for decorative fish such as coy. And I plan to install a 300-500 gallon tank outside the greenhouse (behind) that will act as a reserve for the pond and a tank for trout or fingerlings. Knowing that hot tubs are meant to retain heat I was thinking about recycling an old one off Craigslist. I shouldn't have to add any extra heat in the winter or cool down the water in the summer if I do that, but if I do, it'll be minimal heat in the winter. It's the summer I have to be concerned about. And that is as simple as draining some water out of the pond and into the exterior garden and refilling the reserve up with cooler water until desired temperatures. Plumbing will be added to the pond to obtain this goal.

I currently have everything set up in a small scale system with synthetic lighting in my garage. I have my early spring seedlings ready to transfer to my new tables (although I haven't ran the plumbing to the temporary tank yet). All seedlings are in the vegetative growth stage due to the amount of hours I have the lighting on them and I plan to keep it that way until I'm ready to move them. The system is currently circulating through a hydroponics tank now. I'm buying some goldfish this weekend to stock the garage tank. Once the fish adjust to their new home I'll thoroughly flush the medium for several days before I convert the system over.

Your opinion?


Old hottubs will likely have chlorine residue, may want to reconsider.  I agree about the surface area and the mix Lloyd talked about.  All goldfish are messy and will grow.  By the time I gave mine 1/4" to start with goldfish away, they were 5" and fat.  I had too many fish for plants.  test the rock with a small amount in a glass jar, add vinegar.  If it foams it has lime.  Don't just take their word.

Your pictures are beautiful.  

If I could afford to reconsider I definitely would. The whole hot tub system will be completely re-plumbed with new, unchlorinated piping and seriously flushed before cycling and bringing to a ph of 5 or less. Only upon 100% personal satisfaction I'll finally then add fish. It will take some patients, but looking at my alternatives, I think it will be cost efficient and reasonable.


Your feedback has been VERY helpful! If there's anything I can share please don't hesitate to ask. If I don't know, I'm not afraid to do my research and get back to you. Until Monday, it was a preasure. Have a great weekend!!!


P.S. Here's a picture of last year's crawling pansies that I still have in bloom:

>.. Goldfish are excellent! They can tolerate the cool, and some of the heat, and they can grow really big quickly in Aquaponics. FYI large goldfish are as decorative as Koi, I have both, and sell as well if you want to later.

>.. My son uses them to power his garage aquaponics system. He is a "maker" and his skills came about through years of fixing things to resell. He also uses lights, as I do. His media is the same smaller gravel and he's been growing lettuce, strawberries, tomatoes, flowers, and more in his little system (old aquarium and an 18'' by 30" by 6'' growbed, similar to yours. His gold fish have grown quite larger since he started.

>.. DO NOT use cheap goldfish, use slightly larger goldfish, say, thumb length. Survival is MUCH better. He feeds them goldfish food which is cheap and readily available. The cost of larger goldfish is a bit more than the cheap ones, but when you figure it as a percentage of the whole system, it is not a large part of the whole. Avoid Walmart goldfish, as they are not well cared for; try friends who are tired of their Goldfish, or pet stores. Try to feed your goldfish only as much as they can readily eat, as any extra is filtered out by the media beds, but feed them several times a day. You could probably feed them before work, after work, and at your bedtime. Substitute school for work if you're going to school or college.

>.. Goldfish and koi are of the carp family, and as such tolerate much more range of acid, base, nitrogen concentrations, and temperature variations than others.

>.. PS, trout do not like corners, and there have been reports of trout banging into walls of the square tanks. Depending on the composition of the walls (concrete versus foam), this can cause damaged trout. Look for a round soft hot tub, like a Softub, for your bigger tank if you are thinking round. They are made of vinyl covered foam, are strong and durable, and often come with a flip-over cover so you can let light in without heating the pool too much. YMMV

>.. When recycling a hot tub, do not use the original pump as it has copper in it and bronze. Excess copper is poisonous to fish and can easily be mysterious as there is not a good test available for copper on the market. Chlorine and bromine and fluorine are all acids, so use baking soda in the initial rinse water (after scrubbing out the tub with soap) then flush several more times with the plain water out of your hose. It is NOT necessary to fill the tub with water at each rinse, but DO rinse until no sign of baking soda (white powder residue) is left.

>.. Go with a pond pump, for the hot tub, as they are often free of copper.

>.. Have you got a water testing kit? You will want to test for Ammonia, Nitrites, and Nitrates at a minimum. Amazon has a good kit for about $25. So do pet stores.

Excellent feedback Lloyd Booth!!! I plan to pick up goldfish this week!!! Most likely Tuesday they will be climatizing. And I will be picking up a testing kit. I have a particulate gage now but I still need to get a water test kit for ammonia, nitrites & nitrates. I ordered a nitrate kit off Amazon but it reads in ppb. Shouldn't I get one that reads in ppm? I know the ph is optimal at 4.5, not to exceed 7. What should the ammonia, nitrates & nitrites read?


It will be a little while before I can get the hot tub but thank you for the detailed information. It sounds as if you have used a hot tub before. It will definitely be thoroughly cleaned & flushed before introducing it to any fish. 

Good morning Jeremy,

>.. You'll find that it is impossible to maintain any specific number in any system that includes live species. There are way too many variables that the creatures and the system itself that can be affected. In my experience, the best to shoot for is a range for each number. For example, a pH of 4.5 is pretty acid and I suspect that plants and fish would suffer; keeping to a pH of 6.0 - 7.2 would probably be better for both plants and fish. Goldfish can tolerate a wide variety of pH, and thus are a good choice.

>.. As you work to achieve a "perfect number," other variables will fall out of range. It also matters how you attack the problem number. Say, perhaps you have high Nitrogen as nitrates; well you can attack this immediately with chemicals, or you can plant much more leafy vegetables which absorb the nitrates. Both are acceptable solutions, as long as the fish are OK. In both cases however, it is necessary to reduce the fish food a bit. Perhaps you will need to reduce the number of fish in your system; it is possible to have too many fish, or too many "BIG fish" for your system.

>.. If the problem is too much Ammonia, look for dead fish(es) trapped in the mechanism. Normally dead fish float due to trapped gases, if you're watching your system every day, you'll see them before they start producing so much ammonia. If you don't see any dead fish, look carefully at the whole plumbing package, as they can get trapped behind, under, inside the plumbing, and thus hard to see.

>.. My point is that you'll find many ways to "treat" your system, but some take longer, while others take less. And every step you take will have consequences, usually unintended, on your system.

>.. Best of luck as you go forward. We're here to help, and all of us love to answer questions, so keep them coming.


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