Backyard Aquaponics
A place to discuss aquaponics

Yay, I got it working!

The no-holes-overflow, or HOB (hang on back) overflow as it's apparently called in the reef community, hangs over the side of the GB. It starts in the stainless steel guard, next to the autosiphon, with a closed piece of 50mm PVC (bell siphon upside down) as intake. Up and over the side goes the 32mm PVC 'water bridge' U, that should always be full of water. After that (against the side of the growbed) is another U, going up to a T-piece. There is always water in the part from the intake to the T-piece. The drain pipe goes out the side of the T-piece; when water comes over the intake in the GB it comes out through the drain pipe straight down into the FT, and an air tube goes out of the top of the T to break the siphoning when the water falls below the intake level (leaving water in the 'water bridge').
There should be no air accumulating in the bridge, because the flow is such that bubbles get sucked out during the siphoning.

This is the overflow intake, next to the autosiphon.


The HOB overflow hangs over the side of the GB.


When the big pump is on, the water rises until it reaches the overflow intake. The overflow starts trickling, and then starts to siphon. However, the flow is not enough to keep the waterlevel from rising further, and it rises until the autosiphon kicks in. The level then quickly falls again to the overflow intake level, where it finds its equilibrium point (overflow trickling again, instead of gushing like the autosiphon). When the pump is turned off, the overflow immediately stops trickling, but the autosiphon goes on to empty the GB.
The two pipes at equilibrium (the overflow trickling):



I admit it's overly complicated for its purpose - I could've just gone with a big standpipe with small holes at the bottom... But I really wanted to keep the autosiphon, and didn't want to remove any media and cut more holes. So I'm glad this works too! I'm still testing how reliably it works with the big pump on a timer, but the last 4 or so cycles (15min on, 45min off) went perfect.

I hope the new pump helps to clean up the FT a bit, because there's lots of muck building up at the bottom. And I really hope that by tomorrow morning the overflow is still working..!

Wow, plenty of aeration from that! Good work Xzorby

Thanks! I'm so glad I put in the new pump, it's working much better!

We had some bad news some time ago. One of the carp had died, but since it died in a bit of PVC with a huge root growing through it, we didn't notice. When I saw the big root growing through the pipe I pulled it out, and out came the dead fish.


After that, I decided that the plant that was in the fish tank (bulrush) needed to be contained in something stronger than a cotton bag full of clay balls. So my gf and I took it out and cleaned it, I also cleaned some muck from the FT, and we put the plant back in, in a nice 60L tub.



The new pump and no-holes-overflow are still working great. The water is crystal clear again! The fish seem to like the new tub in the FT; even the biggest fish sometimes "jump" in and lay down on the gravel: http://www.youtube.com/watch?v=e4Hy3wH-Rtk
Recently, the temperature has been dropping a bit, and the fish are eating a lot less now.


I've been working on my own cycle timer, using a Freeduino and a solid state relay. It's working, but I haven't hooked it up to the pump yet. It's much more accurate than the mechanical 15-minute timer I have; this thing can be programmed to the millisecond! I've also got a 16x2 LCD screen, a light sensor, some temperature sensors and some other stuff that I will eventually hook up to monitor and control my system. I think I'll make a seperate topic about that when I continue.


Today I bought a plastic tank. It's quite big, and it was used for storing molasses. My dad and I cleaned it out and put it on the balcony. We'll use it for storing rainwater, which we'll use to fill the fish tank with, and also for watering the garden. It's a bit oversized; around 110x80x80cm so probably holds 400-600 liters! It fits nicely on the balcony and was only 25 euros.

Just a quick update.

It's been a cold winter here, up till now - coldest I can remember (okay, I'm only 20 years old, but still)..
We've had lots of snow and it was below freezing for about a week or two. I wasn't home at the time, but my sis said there was a thick layer of ice on top of the pond - with the pump and siphon still working! She broke some of the ice so the surface was never completely frozen, but at one point the GB was frozen over to such an extent that my dad turned off the pump for a few days.

It's slightly warmer now and just about all the ice is gone.
The no-holes overflow worked fine initially, but I can't seem to get it working any more. I think the frost and turning off the pump broke the siphon and when I started it up again it broke siphon the day after. It means that after 10 minutes of growbed filling it overflows for about 5 minutes, but it isn't much of a problem because the FT is right underneath it. I hope to fix it in the weekend, it was fun to try but I think I'll replace it with a real overflow (this one is too unreliable).

Fish are doing fine, and even eating a bit now there's no more ice. All the plants that were in the GB seem to have survived, too.

Here's some pictures!

6 weeks ago, a cute little bird looking for strawberries.


5 weeks ago, LOTS and LOTS of snow, my sis made a snow-horse!


3 weeks ago, quite some rain and snow, so the FT was very full. Here you see the autosiphon draining under the surface (and a few days later it was still working, even though the surface eventually froze over!)


2 weeks ago, I think there was some overflowing while I was gone, looking at the wall of ice that the net had become



Today, snow again!


It also rained a bit, last night, so for the first time we caught our very own roof rainwater! Yay, from now on, no more toxic tap water for our fishies!
Quite some pressure, from the balcony.. More than I'd hoped! With some more PVC bits I reckon we can use it to water the rest of the garden, too.
Ugh, the GB is a mess! Dead stuff everywhere, should clean up!



Anyway, I fixed the overflowing problem (unreliable no-holes-overflow) the easy way, by switching to a different pump timing. Previously, we had a 15 minute on, 45 minute off schedule. Now the pump only goes on for 5 minutes (and off for 55). The autosiphon kicks in after about a minute, after which the water level keeps rising slowly, but in only 5 minutes of pumping it stays below the edge of the GB. Less pumping also saves energy of course (but I think it's still enough for adequate filtration).

Hey Thomas

Your fish must be very hardy. I have this image of you cutting a hole through ice on the top of the tank and fishing for them like an eskimo.

Love your sister's ice horse, she must be very tallented.

Haha, a bit like this?

This is my grandfather cutting up some ice so the fish can get oxygen. He likes to do things around the house when he comes over. I'm very happy with my family; I'm not home a lot so without them everything would be dead right now!

Although, you're right, the fish are pretty hardy; the carp are even eating again! I'm not sure about the rudd though; I haven't seen them in a while (no no they're resting!).

Thomas, love the pics. Your system is tuff as nails.

What sort of readings are you getting by the way? I would have thought at those temperatures your bacteria would well and truely be out of action, if not dead!?

What plants have lived through the cold?

That is a pretty impressive effort if your bacteria are still viable - maybe they go into hibernation ! Other types certainly survive in different unfriendly environments around the globe.

I haven't done any readings in a looong time, since last year the readings were all the same anyway (no matter what time of the year) - never any ammonia or nitrite, and only a small amount of nitrate (around 4ppm). I don't think it will be any different now.

I'm not sure about the bacteria! Last year we had some frost, yet they still survived alright. But we haven't had a cold winter like this one yet. I do hope they go into hibernation or something..

The only plants that are still green are the spring onions and the strawberries. There were also a lot of radishes all over the system, but they died with all the frost (good thing, by the way, we don't really like them).


This morning the fish were so active, they'd actually knocked the hose off of the pump! It could be stress, but I've seen stressed fish in my system and they don't look very stressed right now, just active. I hope my dad has a stainless steel thingy to keep the hose on (he said he might) - we've had this problem with the other pump as well.

When I get back I'll do some readings!

It’s been over a year since the last update, and the system’s been doing well despite my/our neglect. So here’s a long update/evaluation and also some information on the system so you don’t need to go through the entire thread to find something.

Fish
We’ve got about 15 carp (ranging from about 20cm to 40cm) and a couple of ide, rudd and goldfish (mostly around 20cm).
All the fish are still doing fine, most have grown quite a bit in the past year. Some of them probably have some sort of parasites, but we haven’t had any unexplained fish deaths in at least a year so I suppose only the strong ones are left in the system.
Our biggest fish (named “Piet”) committed suicide last summer, by jumping out. I had removed the net for some reason, the day before, and forgot to put it back up. He was already dead when I found him. We didn’t eat him.
I should really stop taking the net down, because this winter a heron caught a couple of the smaller fish. We also have a few new cats in the neighbourhood that seem very interested in the fish..
This winter, and the previous one too, were very cold by Dutch standards. But despite weeks of below-freezing temperatures, the fish seemed to cope really well. I think they went into hibernation or something, during the winter. I don’t feed them at all when it’s freezing, and if it’s below 10 degrees Celsius outside I only feed them a bit when it’s sunny. During the summer, however, they eat lots.

Fish tank
Our fish tank is made out of 1mm Firestone EPDM rubber liner. It is dug into the ground and there is very little material between the rubber and the soil (see also viewtopic.php?p=59642#p59642). We’ve had troubles with leaking at the beginning. The size is around 300x120x60cm and it holds about 2000l.
I suspect that there is still a small leak somewhere, but it’s not big enough to be a cause for concern. Because of the small amount of material between the rubber and the soil, some of the sides have ‘collapsed’ – they’re not vertical walls any more, but have a bit of a bulge. There hasn’t been any ‘collapsing’ in the past year or so, though, and while I was a bit worried at the beginning I don’t think this is a problem either.
The lack of insulation between the tank and the soil means that it’s thermally coupled to the ground, keeping the water warmer during the winter and cooler during the summer. Despite the previous long and cold winters, the water only completely froze over once (see picture posted 25/1/2010) and even then that was only a very thin layer of ice. In the summer, though, the water temperature doesn’t get above 15 degrees Celsius, but since we have cold water fish, this is not a problem.

Plants and other things in the fish tank
I previously had a bulrush in the fish tank, for the fish to hide around. It didn’t get enough light and died after about two years. I don’t have plans for new plants in the fish tank at this moment. There are some big PVC pieces for the smaller fish to hide in and behind, though.

Water quality and bacteria
The system has always had a pH of around 6-6,5, and NH3-NO2-NO3 readings have always been between 0-0-0 and 0-0-8 or so.. Despite the cold water (often 0 degrees Celsius in the winter) and sometimes heavy feeding in early spring, we’ve never had any ammonia/nitrite spikes. I guess occasionally flooding and draining the growbed keeps it from completely freezing, so somehow the bacteria survive. The plants are apparently doing a good job at eating up all the nutrients. We’ve never had any algae problems and the water smells and tastes good. After the system’s first year, I haven’t done many readings because the system is very stabile.

Plants in the growbed
We have a ~700l growbed filled with broken expanded clay. It’s the same stuff as hydroton, but because it contains many different shapes (instead of just balls), it’s a bit more dense. The stuff is normally used for landscaping, and I hear that they use it in Belgium for insulation under houses.
The strawberries have been doing fine, despite the plants being very old. The plants are very crowded, though; hundreds of crowns packed tightly together. They make a lot of leaves, and probably few strawberries for so many plants, but despite that we’ve had a nice harvest last year.
This week I’ve pulled out all the strawberries, split them into single crowns, and replanted them spaced about 10-15 cm apart. There were so many plants that I’ve planted around 30 plants around the edges of the growbed, 40 plants in soil all over our garden, at least 40 plants in soil pots and another 40 in the middle of the growbed because I didn’t have any pots left (I’ll use them to replace any weak plants, and probably put some more in pots later on). I’m thinking about also trying a cucumber plant and a fig tree this year.
We’ve had bergamot in the system (big plant with lots of flowers, leaves can be used for tea) that I suspect took a lot of nutrients. It always did really well, but this week I decided that I only want food crops in the aquaponics system; pulled it out and planted it in soil instead. I also took out the lupines, they did very well too, but again not a food crop (though it is a nitrogen-fixing legume). The blackcurrant bush that I almost killed when it was in the soil has recovered well in the aquaponics system. Onions and radishes did well in the system, too, but leafy greens such as lettuce didn’t at all (possibly because the rest of the plants took up all the nitrogen). We’ve tried tomatoes a couple of times, with mixed results: I think our weather is too moist to grow them without cover, and possibly our system doesn’t provide enough nutrients. Another possible cause for some plants not doing so well is that the water and GB medium is just too cold during the growing season, because of the tank being dug in. Also, the GB only gets about 5-8 hours of direct sunlight per day (not sure how much exactly), and the part nearest to the house even less.

Growbed construction
The growbed is made out of 8 hardwood planks around the sides (4x 300cm, 4x 90cm) and a bottom made out of plywood (the type used for concrete pouring). The planks are 145x24mm (if I recall correctly), the plywood is 18mm thick and they’re attached by a 40x40mm hardwood beam in the bottom. The growbed is attached to the two poles at the front using stainless steel screws, and at the back it is attached to the wall and one of the poles from the fence. The upper and lower layers of planks are attached to each other using steel plates for added rigidity. The growbed is lined with cheap 0,5mm PVC liner glued to the wood around the top edges. More about construction (with pictures) here: viewtopic.php?p=66870#p66870
The two front ‘poles’ are 90x90mm hardwood, and the rubber liner from the fishtank goes around them (so they’re not actually in the water). They stand on 600x400mm tiles; the entire bottom of the growbed is covered with these heavy tiles as a foundation. The top of the fish tank is made out of the same planks used for the growbed, and is also attached to the wall, the two front poles and the pole from the fence using screws. The front and the right side rest on the ground level 600x400mm tiles.
While the growbed is built strong enough for now, I fear that the bottom of the growbed will not last very long. The plywood is starting to bulge; this needs to be fixed soon.
Also, it turns out that the pole from the fence (that both the growbed and the top of the fish tank are attached to) is sinking into the ground. The fence was built by the neighbours, and I think they didn’t put a tile underneath it.. The ground around where we live is very much sand, so we should’ve anticipated this problem. For now, the fact that the top of the fish tank is attached to it is probably preventing the thing from sinking further (it doesn’t seem to have sunk any more in the past couple of months) but this is also a problem that has to be fixed soon.
We’re planning to put a new bottom in the growbed after this growing season. The bottom will be of different (stronger) design than the current one. The GB will have to be emptied, which also gives us the opportunity to fix the sinking-pole-problem.
The glue that keeps the PVC liner (0,5mm) to the growbed (it’s only glued at the top) is coming loose in some places, but this doesn’t seem to be a problem since the GB media is keeping it in place. I’m also suspecting a small leak in the liner, but it might also be water overflowing over the back right edge of the liner because of the fence pole sinking. The liner is very cheap though, so we’ll just replace it together with the GB bottom.

Pumps, timers and pump hose
We started out with a 30W 1800l/h fountain pump, pumping continuously. This worked well, but the pump clogged up very easily and during the summer needed weekly cleaning. The pump was replaced by a 200W 6000l/h bilge pump, put on a home-made Arduino-based timer. Pump times with this bigger pump were 5 minutes on, 55 minutes off (during winter) to 5 minutes on, 25 minutes off (during the summer). If I recall collectly, the pump hose is 32mm and it goes into a 32mm PVC pipe with lots of holes drilled in the bottom.
The big 200W pump on the timer worked very well; while the old one clogged up and had to be cleaned every week, the new big one pumps up solids more easily and during its life didn’t need to be cleaned at all. The timer also worked perfectly.
However, a few months ago, the power in the entire house went out. It took quite a while to figure out that it was the pump, tripping the residual current breaker – the pump motor is broken. I only just found out that it is still under warranty though, so I’ll send it back. The rotor is still fine. I think maybe the water in the pump hose froze during the 55 minute off-time, but even then that shouldn’t cause the motor to break in this way. For now, we put the old (small) pump back (continuously on).
The 32mm PVC pipe with holes is fine, it hasn’t ever clogged up and so far there haven’t been any roots growing into it. The flexible pump hose however has been a bit of a problem, since during the summer the fish tend to knock it off the pump (causing the pump to still pump water around but the water isn’t filtered or oxygenated because of course it doesn’t reach the GB). This was fixed using a stainless steel fastener thingy (can’t find the right word). Also, the hose became very brittle when it was freezing outside, I actually broke it off when pulling the broken big pump out of the water (it was well below freezing that day, though).

Siphon and GB overflow
The growbed houses an simple autosiphon, with a 32mm standpipe (25mm inner diameter) and a 50mm bell (if I recall correctly). It has a big stainless steel mesh guard around it, keeping the growbed media back. When we got the new bigger pump, the capacity of the pump was more than the siphon could suck out, so we needed an overflow; I went for a no-holes-overflow (or hang-on-back (HOB) overflow) out of 32mm PVC.
The old siphon always worked fine with the old pump. So far, it hasn’t ever clogged up, and I don’t think it ever failed in a way that the growbed overflowed. The HOB overflow we used together with the autosiphon (after we got the bigger pump), also worked surprisingly well, when it wasn’t freezing. The frost eventually caused it to break siphon. A ‘real’ through-the-GB-wall overflow will be more reliable and is planned to be implemented later on.
The combination of siphon and overflow, together with a big pump on a timer, works very well; the inflow is such that the water rises fast enough to trip the autosiphon, then continues to rise slowly until it reaches the overflow where the water level stabilises. When the pump is shut off, the autosiphon quickly empties the entire bed and stops easily.
Now we’re running the small pump again, the autosiphon is starting to get less reliable; while it starts just fine, it has trouble stopping right. I think the air tube might be partially blocked. I’m thinking about converting it to an Affnan.
The siphon guard works perfectly. Even though there have always been strawberry plants only 10cm away from it, it has never clogged up and for some reason no roots have ever gone through it. It has no top cover, but somehow no leaves or other things fell into it either in the past few years (even though during the summer it was always buried under a thick layer of strawberry leaves).

Rainwater storage on the balcony
We had a rainwater storage tank on the balcony, with a capacity of around 500l. Water from the roof went directly into the tank, and a 25mm hose with ball valve made it possible to use it to water the garden or top up the AP system a story down.
While the rainwater tank was perfect for watering the garden with, some idiot construction guy broke it when doing some work on the balcony. To his defence, though, the plastic had hardened from UV. Still looking for a cheap tank to replace this one.

Control system
I’ve had plans for a control system. This is why I used an Arduino as a pump timer; because I can add sensors and other things to it later on. The idea was to measure (amongst other things) the water temperature, water height and light intensity, and use those values to control the pump (smart timer: only pump when needed, saving energy) and a fish feeder. This project, however, was maybe a little too ambitious, and is currently on hold.

Neccesary-hardware-things-to-do-list
Short-term: get the broken 200W pump repaired/replaced (should still be under warranty), add a ‘real’ overflow to the growbed (and possibly a fish tank overflow as well).
At the end of the growing season: empty the growbed, replace the bottom (making the entire growbed stronger) and fix the sinking fence-pole.

More plans
I’m thinking about adding a 60l tub to the system, with its own autosiphon. It’ll be placed much lower than the big growbed, to the left of it; that should give a lot more vertical space to grow tomatoes. It’d be watered with a hose coming from the overflow of the big bed.
An extra ‘strawberry trough’ added to the front of the growbed (but the top being around 25cm lower) would be very nice and relatively simple to build. I really want to focus on strawberries, since I’m probably moving out of the house when I’m going to study again this September (biosystems engineering). Strawberries are very easy for my dad and sister to maintain when I’m not home, and they have proven to do very well in this aquaponics system (despite neglect), and of course strawberries taste great.

TL;DR - Images
Fish suicide (R.I.P. Piet, April 2010):

Overview (May 2010):

Freshly picked strawberries from the system (July 2010):

The system, last Monday (before cleanup):

Yesterday, after cleaning and replanting strawberries (the ones not on the edges are only there temporarily):

Close-up on replanted strawberries, siphon and liner glue coming loose:

Good to hear from you Thomas... and glad to hear your system is still kicking along...

HI Thomas, great update!

Yeah, great update and recap ... Shame about Piet, looks like a nice size, any idea how big he was?

51cm, 2.8kg.. In hindsight, of course, we should've just eaten him.