Saturday, October 30, 2010


I just realized I had not posted any pictures of my fish, so here they are! I also realize I was so tired last weekend when I posted my update, that I mistakenly said I had 5 large fish. Well, there are six. Plus, there are two fingerlings. Those I couldn't take pictures of or even find, but they must be in there or they'd be floating on top.

I've also decided to name these and all future fish. There is just nothing better than a personal connection. I've established an elaborate and sophisticated naming system for said purpose.

Basically, these fish are named as follows: Grill-Dinner-1; Grill-Dinner-2; Grill-Dinner-3; Grill-Dinner-4; Grill-Dinner-5; and the cutest one of all, Grill-Dinner-6. If you would like detailed instructions and the basic formula for my naming algorithm, please write and send $29.99. :)

Where the Wild Pre-Grill-Dinner Things Are:


My tank, when full, and when my system is fully operational, should hold around 180 fish. That's a lot of BBQs. The naming system though, is guaranteed to work for well over that number, so act now while supplies last.

Week One: Oh-*hit and Yeehaw!

The phone rang Tuesday evening. It was my caretaker at the farm, where my AP system is. I didn't leave him with with very many instructions, and this is a completely alien concept to him, and just about anyone else in Costa Rica (hydroponics is fairly well know, but aquaponics? - fuggedaboutit). The main reason for the lack of info is he leaves Saturday at noon and I didn't finish getting everything set up until Sunday. I didn't even get the fish until Sunday. So Sunday I left the farm and went back to the "real" world, without being able to give him almost any instructions. I left everything in the hands of fate and my trusty (and well-tested) back-up pump.

The point being is, I knew something had to have happened for him to be calling. Something bad. Dead fish, I assumed.

Fortunately, it was nothing anywhere near that bad. He explained, after much excitement, that one of my larger grow beds (of the cattle reservoir variety) had flipped over. Apparently, one of the footings gave way, causing it to tilt. The massive weight of the grow bed caused the rest of it to flip. Of course, that broke some pipes, sending water everywhere. By the time he discovered it, the water in the tank was near empty. If a few more minutes had passed, my pump would have been sucking air, probably burning out, and the fish would have been toast as well.

Fortunately, he did find it on time, and I was able to explain to him over the phone what to do: disconnect both cattle-reservoir grow beds, cap the pipe, and leave the bath-tub grow bed on. And, refill the tank of course.

I have to hand it to Carlitos, my caretaker. He has no idea what any of this stuff is. He probably did not get past 4th grade (through no fault of his own), does not know how to read, and to top it off, he has a horrible stutter. It took me about 5 minutes to even understand what it was he was explaining to me. Anyway, most people think he's a bit "slow" but it's just the way he comes across. He's actually pretty quick in a fix.

I spoke with him again Wednesday and Thursday, just to make sure everything was OK. He and a helper also poured concrete footings in the spots under each grow table leg. I won't even get into what I had them sitting on before. Suffice to say, there is a reason I don't have a materials engineering degree.

Here's the table that flipped and bent out of shape. It's sitting upside-down on top of a non-damaged table:

Now, the system basically ran for one week. To be more precise, it ran for three days roughly without problems. Then it ran with one grow bed attached for another four days. It's a good thing in retrospect that I only started with as many fish as I did, as I doubt one grow bed, and bath-tub sized one at that, would have been able to handle the amonia put out by a large number of fish.

The Yeehaw news is a result of my tests. Amonia levels are in the sweetspot range of .25 - .50 ppm and nitrate levels are through the roof. Here are my water tests:

I was not expecting nitrate levels to be so high so fast. This is great news as it means I have both ammonia-to-nitrite producing bacteria and nitrite-to-nitrate producing bacteria in my system after such a short time. I can only guess that because the gravel sat in my driveway for so long, and maybe because I have chickens that love to "liberate" themselves all over the place, that I had good levels of bacteria in my gravel to start with.

I'm actually a little worried about the nitrate levels. It does not cause immediate harm to fish - and certainly is not anywhere near as poisonous as ammonia is to fish, but it does seem quite high. I'll have to do some research to find out if I should be really worried or not.

In any case, the solution to high nitrate levels is to add more grow beds and plants. So I spent all Saturday (today) resuscitating one of my larger grow beds. Just filling the thing with gravel is more exercise than I usually get (none). I also hooked up my back-up pump to the fish tank for a while so I could use my main pump to wash the gravel in the grow bed, using another grow bed to catch the water and recycle it through the gravel-filled bed:

There is gravel in the upper bed, I promise! After washing it enough times to have the water come out clear in the bottom, I hooked it up to the system and put my tank pump back. I wasted a ton of water. Good thing water is cheap and plentiful here. If I didn't have cheap water, I guess I would have just hooked it up as is. I would not have been able to see my fish for several days, but supposedly, that doesn't hurt them. I don't know - I like clean water and to be able to see my fish.

I'll probably plant some things in the second grow bed tomorrow. I'll hook up the remaining beds as soon as I can. Unfortunately, only being able to be around on weekends puts a severe slow-down on things. On the other hand, it makes me work my rear end off every minute I'm here!

And now, it's beer-o-clock.

Sunday, October 24, 2010

Day 2 - Got my fish!

Picked up 4 female and two male tilapias, all close to fully grown, and two fingerlings. Could not get my hands on any more fingerlings unfortunately, but it's a start. The place I got them at is no more than ten minutes from my place, so I was able to transport them in some old plastic buckets without the need to worry about oxygenation.

I also adjusted the height of the upsteens on two of my grow beds. The water level just wasn't reaching the roots, and upon inspection, I realized the level was well below the recommended 5cm depth (from gravel level down). The plants in the bath tub were fine, as the water level there was reaching about 5 cm below the top of the gravel.

My PH level got back up to 8. It must have something to do with the gravel. I squeezed one lemon into the system and will add one per day until the level gets below 7. The high PH shouldn't hurt the fish, but it definitely won't be good for the plants. This will all be academic once the system stabilizes, but for now, I'll just have to keep an eye on it.

Day 2

The tank was just as murky as the day before. While pondering what to do about this, I decided the investigate the PH situation a little more. I found both my house water and spring water had PH levels well below my tank water. Therefore, whatever caused my PH to be over 8 came from the gravel, the grow beds, or the pipes. While my spring water PH was higher than the house (house water read about 6.2; spring water 6.8-7.0), neither was anywhere close to the tank water.

That made my decision to change the entire water quite easy, so out it went. This allowed me to clean out all the small particles that were in the fish tank as well. After refilling it and running a few flood and drain cycles, the water remains much clearer than before, and the PH is in the 6.5-7.0 range. Not exactly where I want it, but much better than before.

Next, I'll be off to a local Tilapia grower for some starter fish!

Saturday, October 23, 2010

New Design - OUT with you half-barrels!!

After trying various half-barrel configurations and bell siphons, I decided half-barrels just aren't the way I want to go. The bell siphon alone takes too much space in each barrel, and having 16 bell siphons just didn't appeal to me. Also, the depth in each barrel is obviously not consistent due to the curvature of the barrel. If I were doing a small system, and just had a few barrels to set up, that would be one thing, but since I am setting up a decent-sized system, I'd rather do it right from the start.

I redesigned my layout based on larger grow beds, of about 525 liters each. After getting quotes from fiber glass shops on these one-off beds, and just as I was about to put a deposit in for an order of four, I discovered a local manufacturer of various rubber-based products, including tanks, pools, and water-reservoirs for cattle. It turns out the cattle reservoirs are perfect! The cost of these was about 40% less than the fiber glass equivalent.

Today I finished setting up the system with these new grow beds. I went ahead and planted what we had available - basil, arugula, and peas. I probably should not have done that before testing the water, which turned about to be PH 8 !! This water comes from a natural spring on the property. I figured that was better than tap water, and other than the PH, it probably is.

I went ahead and added crushed egg shells to the system to reduce the PH. I placed them in a make-shift left-over mesh-bag from my greenhouse screens, tying that to a plastic bottle, and floating it in the fish tank.

I have no idea how long it takes for the calcium carbonate to dissolve and bring the PH down, but egg shells are supposed to make for a good PH regulator in AP systems. I'll test it tomorrow and see if it has come down any. When it gets below 7, I will add my Tilapia.

For now, I'm priming the system using "Humonia".

Here some picks of Day 1:

All three bell siphons going. Yes, the water is damn murky. That's due to the gravel, and should settle out in a few days.

This grow bed is a used bath tub. If I could have fount five more of these, I would not have bothered with the water-reservoirs for cattle.

Backup pump system and air pump.

Thursday, October 7, 2010

Basic Components - Main Fish Tank Pump

When you buy a pump, the main thing you need to consider is how much water it will be required to move. Whatever your tank size is, you should plan on moving something close to the entire amount of water through the system every hour.

I based my pump size on the maximum capacity of my tank, which is 1,600 liters. It's a "Little Giant" brand pump, made in USA (I didn't know they still made stuff there). It has a 500-gallon -per-hour flow capacity at 1' head. That translates into over 1,800 liters per hour at 1' and enough to move all my water every hour at the height I plan on pumping to. Here are some pics:

Basic Components - Connecting Bell Siphon to Grow Bed

This is pretty simple, but worth explaining.

Your bell siphon drain pipe needs to go through a hole at the bottom of the grow bed. Naturally, you want the pipe to drain only when you want it to and need to make sure the seal is otherwise tight.

Cut a hole at the bottom of the grow bed where you want the drain to go. Use a hole-saw that is just slightly larger than the male adaptor you want to connect to the end of the 1" drain pipe.

Ensure the male adaptor goes through the hole, and screw it to a female adaptor on the other side. You may need to buy some rubber washers to ensure there is no space between the male adaptor and the grow bed floor. This is especially critical in a barrel system, which has a curved floor.

In order to get the male and female adaptors to fit well together, you may need to cut the male adaptor down so that the amount of thread on the other side is just enough to tighten the female adaptor down tight.

Cut and uncut male adaptor with and without washer.

Test your siphon and make sure it works!

Basic Components - Bell Siphon

The following are pics of my bell siphon. It is based entirely on the Affnan siphon, which has several advantages, namely: it shuts itself off without the need for a cut-off air-hose, which are reported to clog easily; it drains faster due to the fact it takes advantage of Bernouli's Principle in its design, and for my time, it's much easier to make than a loop siphon or anything else I found.

Here's the bell itself. This can be made with a hack saw and some elbow grease, or if you're handy with a chop saw, you can make the horizontal cuts very carefully with a chop saw, and the vertical cuts with a hacksaw or jigsaw.

My bell uses a 4-inch pipe (100mm Imperial units). The siphon is a 3" - 1" (75mm-25mm) reduction connecting to a 1-inch pipe (25mm).

What is missing is a picture of the filter housing, which I will upload next time I'm at the farm. The filter is a 6-inch pipe with many small holes drilled into it.

The only disadvantage of this system is that the siphon, once it's fully assembled with its filter, takes up considerable space. This is amplified by the fact my beds are only 100-liter half-barrels. However, I am going to change my barrels to much larger grow beds (more on that later), and keep these bell siphons. That will reduce complications (bell siphons instead of 16) and provide more grow space.

Here I was just testing the siphon. The broken pieces of blocks are just to stabilize the barrel as it fills with water.