Aquaponics - Overflow

I clawed my way out of my sickbed at the crack of noon today to discover my fish tank overflowing.

Growbed on top of fish tank

My new aquaponics arrangement looks like this.

I think it looks quite neat in its new position and new configuration, but sometimes looks can be deceiving.

Deformation of the fish tank causing a spill

A behind the scenes peek reveals a bit of a problem with distortion.

The existing frame was slightly thinner when turned on its side, and no longer affords support to the side of the fish tank.

The result was to allow the half barrel to deform in such a way as to spill water out. Luckily it didn't spill enough to endanger fish or pumps.

Pumps, like fish, hate it when there's no water overhead. I'm not really sure what fish see in it, but pumps tend to use water as lubricant, and for cooling.

wire holding fish tank in shape

As usual wire came to the rescue. I wrapped it around the entire thing.

wire tangle

I then twisted it into this traditional Australian wire knot known as a "Tangle".

The Australian history of using wire to solve our problems is similar to that of the Swiss in the making of the holes in Swiss Cheese.

I really like the way this camera captures blue.

Aquaponics - Pump change

I put a new (to me) pump in the blue barrel system and put it on a $3.99 timer so that now it runs for 15 minutes out of every 90 minutes. A lot of people in aquaponics seem to do this. This is because it pumps so much more water than the other one did. I'm not sure how it will go when there is fish in because I'm not sure if that will be enough oxygenation. I'm not sure about some stuff sometimes. I also have an old aquarium air pump, so that might come into play to solve the lack of oxygenation issue.

It looks like the system is cycled and running steadily so its time to get some fish!

Aquaponics - New pump and powerhead

My old pump looks like this. Yes those opposing wire loops I added are in fact the new front bearing. This is the pump thats been running for the last 45 days in the small blue barrel test system.

I took delivery of the new pump and powerhead. This is for the second, larger aquaponics system. The pump is the big box and the powerhead is the small ball shaped thing on the top left.

The pump will shift 5000 litres per hour at zero head. That is to say if all you were using it for as a stirrer it would shift 5000 lph but if you want it to move water uphill, the amount of water it can move tapers off depending on how high you are trying to move it.

For some crazy reason not all pumps tell you how much they can pump at any given height. This one only tells you that it can pump to a maximum head of 5 metres. That means you will get 1 drop per hour at 5 metres . From what I'v read and seen, at 2.5 metres you can expect a bit less than half of its maximum output. So I'm hoping this one will pump around 2500 litres per hour at 2 meters head. It might turn out to be a bit more than 2 metres so I made sure there was plenty of excess. I hope. All I need is 1000 litres per hour so It shouldnt matter.

The pump is 150 watts but will only run for a few minutes every hour. The powerhead on the other hand will run all the time in the fish tank, but is only 12 watts even though it also moves 5000 litres per hour. The powerhead cant lift water at all and is there only for its ability to stir water to aid oxygenation. The powerhead's other function is to create a slight whirl pool which will make solid fish waste gravitate to the center. Once there it will be picked up by the overflow outlet. and piped to the pre-filter.

Aquaponics - Flood and drain

Plants seem to like it when their roots are not too wet and not too dry. Goldilocks would have us set the moisture level juuuust right, but in aquaponics, there is a better way. Flood and drain.

In our blue barrel system (pictured here at day one) we have half a barrel at ground level as a fish tank, and half raised above the fish tank as a grow bed (within the online forums you will see FT as fish tank and GB as grow or garden bed)
                                                                                                                

This allows us to pump water up to the grow bed and have it drain back down with gravity. But rather than have it running all the time the plants prefer to get some water, then some air, to their roots. One very simple way of doing this is to use an auto-siphon.

An auto-siphon allows us to fill the grow bed with nutrient rich water to a predetermined level, and then have the water dump back out into the fish tank bellow, exposing our plant's roots to the air. Plants love that kind of thing. And the fish love the circulating water. Keeping the water moving oxygenates it and running it through the grow beds filters it.                               

A bell auto-siphon would look something like this if someone were to make an animation of one working ...

- water is pumped in at the top from the fish tank (FT not shown)
- when the water level rises to the top of the standpipe (the standpipe is the innermost pipe) it starts to overflow.
- As the standpipe fills and the water flows down the tube and back into the fish tank, it forms a siphon.
- the small amount of air left at the top of the bell (the bell is the bit that surrounds the standpipe) is sucked down with the water and the grow bed quickly drains back into the fish tank.
- when the grow bed level gets to the bottom of the bell the siphon is broken and the draining action stops
- the water is always running in but the siphon is designed to allow water to flow out faster than it comes in
- the result of this is a flood and drain cycle that plants love.

Other beasties in the grow bed love this flood and drain as well but more on that later.