Why Round is Better All Around

Just because I haven't been blogging doesn't mean I haven't been busy.  It means I have been too busy to blog!

Here in South Florida, what every one else calls winter is what we call our growing season.  It is the only time when temperatures, humidity levels, and rainfall all fall back into levels that support hearty and healthy plant growth.

In our own aquaponic systems we have mints, onions, peppers, tomatoes, brussels sprouts, eggplant, arugula and endive chugging along.  In soil we have tomatoes and peppers.  Each and everyone has appeared to have had a very merry Christmas and are starting off the new year great.

Things weren't the same over at the Together We Stand gardens.  The aerator to the fish tanks gave up the ghost. Fish croaked (and these fish are tilapia not croakers - a totally different fish but I digress).  Ammonia levels spiked. Fish croaked.  Ammonia levels went higher.  Well you get the picture.  We were stuck in a closed loop of high ammonia levels and dead fish.  Significant water changes were only making a marginal difference.  We lost over 60 fish in one day!  At this rate, this aquaponic garden was not going to survive.  It was time for detective work.

We started with what we knew to be true.  Aeration had been restored.  Dissolved oxygen should not be the culprit. Even after a couple of 60% water changes ammonia levels continued to be off the charts. The fish were not being fed so they weren't making the ammonia and after removing the dead fish the levels did not come down.  There had to be something we were missing....and there was.

The fish tanks in use are designed with grooves on the inside for placing dividers.  The bottom of the tank is a series of three inverted pyramids.  This is supposed to allow the grower to divide the tank into three areas to separate fish of different sizes.  If you don't understand the description, here is a picture (which should be good for at least 1,000 words).

In reality what this actually does is provide a very deep area in which something like a dead fish can settle. Yes folks, that is what turned out to be the source of our ammonia problem.  After draining the tanks down  to about 25% we were able to see the 13 dead fish that had settled in those inverted pyramids.  When the aerator failed, not all the fish that died had floated. Some had settled and that was the source of the ammonia.  Once those areas were cleaned and the tanks refilled, the ammonia levels  went down and stayed down. I don't want to live those 2 days again.  But, with the mystery solved on the third day we were back on track. 

Dr. James Rakocy, the father of aquaponics has always advocated for round fish tanks.  You can't hide in the corners if there aren't any corners.  Now even though these tanks have radius corners at the edges, they still have corners of a sort on the bottom.  So to the adage that tanks should be round, lets add that they should have flat bottoms.

After all, how can your garden survive if the fish themselves can't survive?