Aquaponics experiment 2013 weeks #6 and #7: sickness begets sickness, algae blooms, first root clog, first ripe tomato, some dead fish and some happy, happy plants

Posted on July 2, 2013 in DIY

For the last two weeks I had been hit pretty hard by the flu and a sinus infection, so it was pretty much impossible to keep a close eye on the aquaponics system. Luckily, it didn’t really need me too badly, with one major exception (more on that later).

I am actually writing this in the beginning of week #8, because I haven’t had the time to write an update between being sick and attending Maker Faire: Kansas City this past weekend.

Plant progress – amazing!

I keep thinking that at a certain point the plants would reach a certain size and begin to slow down, but they obviously have not reached that point yet! Every day that I come in to check on the plants they seem to be just a little bit bigger, to the point that they are almost going out of control! Obviously these guys are very, very happy in their new home.

On the far left bed I have some buttercrunch lettuce, which seems to be especially happy. The tallest plant has reached a height of 2 feet! I have sampled the leaves and they seem pretty nice, though a little bit bitter. Maybe that will get better after a while. The lettuce has been growing so much that it seems to be choking itself! I will be harvesting the outer leaves this week to let the inner leaves breathe a bit more freely.

The broccoli plants are nice and tall and should begin developing their heads soon.

100_4837On the right bed are some cucumbers, squash, cherry tomatoes, eggplants and jalapenos. All of these are doing fantastic! All of these plants have begun to flower and producing small fruits. In fact, the cherry tomato plant had one present for me already! A nice ripe tomato that fell right off when I touched it. It tasted great; very juicy with a not-too-thick skin. Nothing beats a sun-warmed cherry tomato!

Plant progress - left bed 6.27.2013 Plant progress - right bed 06.27.2013 Plant progress - 07.01.2013 Plant progress - right bed 07.01.2013

Chemical tests – sustaining a functional nitrogen cycle

100_4839The chemical levels haven’t changed a bit in the last couple weeks, which is a very good sign. It means that the nitrogen cycle necessary for a sustainable system is established and working correctly. I like the idea that measuring nothing is a sign of a system health!

Right now, all of the ammonia produced by the fish and decomposing food is being converted into nitrites, which are then all being converted into nitrates. Finally, the plants gobble up all of the nitrates, leaving no waste! Such an incredible thought to me!

Ideally I’d like for the nitrates to be a little bit higher, which would mean that the plants have more than enough food. But they seem to be content right now to feed off of what is available.

Roots clogging up the right loop siphon

The plant growth is so great that roots had completely clogged up the right bed’s loop siphon over the weekend. I dug up the cucumber plant that sits right over the siphon’s bulkhead and dug through the gravel to get to the bulkhead itself. I found a wad of roots wrapped around the bulkhead, which I removed. Water flow immediately went back to normal.

With the gravel all dug up and was able to take a look at the amount of root growth that was going on – it seems that roots have pervaded the entire gravel bed! Each plant has a very nice, dense blob of roots right at it’s base, with tons of thin roots spidering out everywhere in the gravel. I hope I didn’t severe too many of these thin roots while digging up the cucumber, but it had to be done.

Algae blooming

When I chose to use clear vinyl tubing for the loop siphons I knew eventually I’d have to deal with algae blooming. Anytime you have water and sunlight, you have algae, which can grow to the point of clogging up the plumbing and causing all sorts of annoying problems.

So far the algae problem is not really serious, but I will be buying some extra tubing as a backup just in case.

I was pretty surprised by how quickly algae had spread in my reserve water tank! I filled it up two weeks ago in case of emergency, but had to dump it all when the algae bloomed. No big problem though.


While I was busy being sick the water level in the fish tank dropped to about 25% of the original level, due to a slow leak on my right grow bed. Over the course of two weeks the water level dropped dramatically, causing the fish to become too crowded (too many fish per gallons of water). Nature has a way of balancing out these sorts of systems, which in this case meant three fish expiring. If I had been able to refill the fish tank I probably would not have lost the fish, but there wasn’t much I could do at the time.

Unfortunate as it is, a few dead fish is to be expected. I consider these fish (and all the others) to be martyrs, because their ammonia jump-started the system and helped it become stable in only three weeks. If my plants start having troubles soon from lack of nutrients I may need to fish for some mature catfish in my area and add them to the tank. But for now, I’ll leave things as they are.

And yes, I filled the tank with lots of fresh water as soon as I was able, so they should be OK now!