Aquaponics--the actual running of the system

This is the aquaponics system--water is circulating between the fish tank and the plant grow bed just beautifully.  

This picture makes it all seem that it was easy and things just went smoothly.  WRONG.


There are a few ways to make an aquaponics system.  One is the fill and drain system, which is where the plant grow bed sits atop the fish tank.  Water is pumped up to the grow bed from the fish tank and gravity assists in the water returning to the fish tank from the grow bed.  It is a nice system but I did not want containers with holes in them--potential leaks nor did I want anything to detract from the window views of the greenhouse.  I chose to use the deep soil benches that the company Cedar Built makes and adapt them for my purpose.  I would use pumps to circulate the water between the fish tank and the plant grow bed.  I liked having the cedar soil benches and wanted a functional system that was aesthetically pleasing as well.  The fish tank dimensions were enough to hold about 350 gallons of water.  The plant grow bed could hold about 100 gallons.  So, a large enough system to start and perfect to provide fish and veggies for me.

Setting up the system was the easy part.  I filled the fish tank and grow bed up with city water.  I added 7 crushed 500 mg vitamin C tablets to the fish tank to bind up the chloramines that were present in my city water.  I took chemical readings of the water using test strips, 5 way test strips from Lifegard.  I added 4 ounces of ammonia to prime the bacteria (however, wrong type of ammonia as it contained surfactant--I later learned what this can do.)  My initial pH reading was 9.0, so I added 5 cups of distilled white vinegar.  The pH went down to 7.5, which was much better.  The pumps were turned on and the water circulated back and forth between the fish tank and plant grow bed and into the vertical grow towers, which drain back into the fish tank.  I had planted the vertical towers with bare root strawberry plants that I had ordered online.  However, getting the water to pump equally between the two beds was a trial.  I tried keeping the pumps on continuously but that was a HUGE mistake.  I let some time elapse and during that time, the fish tank overflowed and I lost half my water.  I also learned that wet wood has different properties than dry wood.  I had not braced the wooden soil benches as they were built to hold dirt which is denser than water.  However, water is a liquid and has different properties and exerts a different force than dirt.  Dry wood could handle that force.  Wet wood could not.  The fish tank bed began to bulge out everywhere.  I had to hurry and figure out a bracing system as the bed was literally bursting open.  The plant grow bed overflowed one time as well and had similar issues but not nearly as bad as the fish tank.  The best part of this bad part was the brick floor could handle all of that water, probably about 200 gallons--the water drained quickly away.

A day later, the pH climbed back up to 9 again.  I used 32 fluid ounces of vinegar this time to bring it back down.  I added the vinegar at 6 am.  I then drove 2 hours to collect my fish order and drove two hours back in my truck with the ac on high--freezing my butt off--but trying to keep the fish alive/with oxygen in their bags for the 2 hour drive home.  At 2 pm, fish in bags were set in fish tank to acclimate them to the fish tank water temperature.  Thirty minutes later, I added the fish to the tanks.  I had bought 2 pounds of feeder fish--fathead minnows and mosquito fish combined.  I also bought 40 bluegill and 40 shell crackers from Carolina Fish Hatchery.  Six hours later, I fed the fish using crushed Rachel Ray cat food.  I noticed my clear water had become murky.

The next day, I noticed 6 dead panfish--bluegill/shellcracker.  I had turned the pumps off overnight so I could rest easy and not worry or get up to check on water levels as still having difficulty keeping the water levels the same in the fish tank/plant grow bed.  Over the next few days, I took readings of the water and the pH stayed about 7 but then started to climb up again.  I found dead panfish or feeder fish each time I went to check the system.  I had even added water from my outdoor pond--full of algae--to help in the system start up. 

I researched more on aquaponics and decided that a timer based system would be better than a continuous flow system.  I bought an outdoor timer and set the pumps up to be turned on for 30 minutes and then shut off for 60 minutes in intervals throughout the day.  I had hoped this might aid in my water level issues.  I allowed the bubbler to be on continuously, 24/7.  Having enough oxygen in the water is a big concern for aquaponics so I wanted to cover all bases.  I had ordered 5 inch long screws and they arrived during this time and I screwed them in areas where the wooden framework was coming apart.  I also bought ruby red minnows from PetSmart to add to the tank as I needed enough fish excrement to start the bacterial processes.

I continued to lose fish daily.  Fish were put in tank on August 25th and by September 4th, I had lost 78 panfish.  (I had probably gotten 100+  panfish as the woman wanted to make sure to cover any DOAs that might have occurred in transit.)  pH continuing to rise so I added more vinegar to assist in lowering it.  My prawns arrived that day and I added them to the fish tank.  pH still too high, so I added 64 ounces of vinegar to fish tank.  Within 15 minutes of doing this, I saw my fish swimming at the top of the tank.  It was beautiful to see my fish and count over 20 panfish.  I was so happy thinking that it would all be okay as I did have some fish left.  HAH!  The fish were swimming at the top of the tank gasping for air as they were dying.  Water got murky again and feeder fish and panfish were found floating dead.  And the water smelled off.  I decided to plant my seedlings in the plant grow bed and see if that would help clean up the water.  I was hoping to save what I could.  I added worms to the plant grow bed and to the vertical towers.  I changed the timer too--pumps were to be on for 30 minutes and then off for 90 minutes.  Any water level differences would easily be dealt with without possible overflows.  However, this meant that I was still babysitting the system and  having to check it numerous times throughout the day and night, only if I turned pumps off would I get to rest.

I spent numerous hours researching aquaponics and starting the system up.  I discovered that vinegar is a very bad chemical to add and use to lower the pH of the system, especially if you are cycling with fish, which I was.  Phosphoric acid was the chemical of choice and thus I ordered some.  (Amazing here as I could order 85% phosphoric acid with ease via Amazon, but had difficulty ordering the expanded clay pellets.  I was allowed to order only 3 bags at a time and wait about 2 weeks in between orders before I could order more.)

By September 8th, all panfish were dead and most of the feeder fish too.  I was still struggling with water levels and adjusting the pump valves to be more in sync.  However, I noticed that the plant grow bed seemed low and I decided to check the water level and discovered it was really low.  I had been taking temperature readings of the greenhouse internal temperature and had noted it was over 100 degrees F for many days.  However, I never took the possibility of water evaporating into account.  The plant grow bed was really low and I was lucky I did not burn my pump motor out.  I added more vitamin C treated city water to the plant grow bed and got the water levels back to proper heights.  By September 12th, the pH was back to over 9.  This was just too high.  I was not sure what was causing this to occur.  The bacteria I needed in the system to convert the ammonia to nitrite and then nitrite to nitrate would not grow at that pH.  I tested my city water straight from the tap and the pH was 7.0.  What was causing this problem?

Initially in the set up, I put lava rocks in the fish tank, along with hornwort plants to create a natural environment at the bottom for the feeder fish and the panfish to reproduce.  Prawns are detritus feeders and they would aid in eating whatever fell to the bottom and the lava rocks/hornwort environment was good for them as well.  I was not sure what was causing the pH to have been so high, but I was concerned it was the lava rocks.  I decided I would take out the rocks, but this would require emptying the tank.  I netted all the minnows and emptied the fish tank.    I kept water in the plant grow bed.  As the water level got lower, the quality of the water was awful--it smelled terrible.  I rinsed out the tank--basically about 400 gallons of water watered my yard that day.

As the fish tank was empty, I decided to reinforce the wooden frame better.  I took out the 5 inch screws and realigned the frame better, added more 4x4's to the bottom for bracing and put the 5 inch screws back in for better strategically placed positions.  I liked this reinforcement work much better.  I really did not want to take the whole frame apart as that would have been days of work.  I refilled the fish tank with vitamin C treated city water and tested the water.  pH was 7.5.  I added the minnows and turned the pumps on.  I allowed the system to run for 5 days and had to adjust water levels every day if not more than once a day.  I was getting tired from this all and a bit discouraged.  However, pH staying at 7.5, so I felt good there.  I did add some phosphoric acid when it arrived to lower the pH a little bit.  I got it to around 7.0.  pH has to be lowered in increments otherwise you can stress the fish.  (I had done even more reading on aquaponics and learning even more.)

I blamed the lava rocks until a friend suggested I do a simple experiment and test them.  I discovered the rocks were NOT at fault.  I did not rinse the lava rocks nor the clay pellets and there was a residue that settled at the bottom of the tank from the pellets--this could have been an issue.  However, I figured that that one overflow where I lost half of my fish tank water would have eliminated most of the residues.  I guess not.

The water levels were still fluctuating and I was so tired of it all--my simple design was not so simple and I began to see why a gravity return of the water from the plant bed was a good idea.  However, I had one more thought and I decided to try it out.  I went and bought two more valves to install in my pump system, figuring the first valve in line would be the macro adjustment and then the second valve would be the micro adjustment.  I added these new valves to both the fish tank and the plant grow bed.  This set up actually worked.  The water levels were not fluctuating as much giving me more time in between to relax and not babysit so much.  Yay.  However, the nitrite levels were climbing and getting way too high.  I had ordered bare root asparagus and planted those.  I was hoping that those plants, along with what was already planted would start to help settle the system.  However, it was the bacteria I was needing desperately.  I had added more pond water to the fish tank as the pond water was already established and thus would have the bacteria I needed--basically priming the system.  I added non iodized table salt to the system to help the fish breath better as nitrite is toxic to them.  (Nitrite binds to the fish hemoglobin converting it to methemoglobin, preventing oxygen from binding.  The chloride ions compete with the nitrite.)  I had bought more ruby reds and lost only about 1/2 of them.

Water levels were still fluctuating slightly and again I went back to reading up on aquaponics--even rereading some information.  I noticed a siphon system and wondered if that might work for me.  I installed a dual siphon system and it is now 3 days hence and water levels are almost steady in the fish tank and plant grow bed.  I have had to adjust just twice in that time frame.  Normally I might have had to adjust twice in one day or less.  The nitrite levels are still too high but are coming down slightly.  There is now nitrate in the system.  So, the second bacteria has started its job but its numbers are not high enough yet to lower the nitrite sufficiently.  And that was another thing I learned in my readings--cycling a tank--meaning establishing the bacteria for the conversion of ammonia to nitrate takes time whether fish are involved in the process or not.  I had read it took time but I guess I did not really think it all through (nor believe it.).  It is far better to do a no fish cycling versus a fish cycling as cycling with fish is stressful to the fish and can cause fish kills.  Doing fishless cycling takes maybe about 10 days to 2 weeks for bacteria to get established.  I am doing cycling with fish so it might take over a month to get everything running smoothly, chemically wise.  I am now running into a time crunch as it is fall and pond restocking deliveries may cease during this time.  Also, Hurricane Florence hit the coast of North Carolina and one fish hatchery place lost a lot of stock, due to 5+ days of no power and are not sure they can provide any fish for their proposed October delivery stock date.  They cancelled the rest of their September stocking delivery dates.  And I have not called the other place as I am not ready to receive bad news from them regarding their upcoming stocking delivery date--I do not know if Hurricane Florence affected them as well.

I did reorder more prawns which should arrive via the mail in about 6 days or so and I am hopeful that the nitrite levels will have come down even more.  If not, I shall put them in a separate tank and wait it out until the nitrite levels are safe or maybe risk it.  I am not sure--and I cannot find literature that says too high a nitrite level is dangerous for them as well.  It probably is.

So, the water in the fish tank is clean smelling and I can see the bottom of my tank and watch the few minnows I have--about 50--swimming around.  I have not found any dead ones in the past two days so I am hopeful these survivors will continue to survive.  All of the dead fish went into the worm composting bin and boy has that bin come alive with lots of creepy crawlers--I am not sure what type of bugs will emerge from the different larva I have been seeing.  However numerous spiders have set up house in the greenhouse so perhaps they will assist in eliminating most of what emerges.

A picture may say a thousand words, but what words they say are different for each admirer.  I added my words to the above picture as I wanted you to know my story.   I am keeping a log of this new endeavor.  Hopefully I will learn from my mistakes and not repeat them (and recording everything will help).