Backyard Aquaponics
A place to discuss aquaponics

Steve/Joel

Will probably take your advice and just buy the perch. I'll let my system with the small tray run for a couple of weeks first though, mainly to just see whether the gravel I bought is able to sustain life. Didn't have pea gravel at my lanscape shop, so bought 10mm drainage gravel. Will cycle with seasol to see how the gravel goes and if no good will search wider for something more suitable.

Others in Brisbane, what do you use/intend to use?

The water in my test system tank got to 12 degrees last night and its not even May yet. Will definitelly have to trial haveing the tank in the shed, tough can't do this with my current little grow bed, as it is perched on top of the tank. Will need to wait until I get my F'Glass one from Murray. This will be run a flood and drain and I can run the pipes through the shed wall.

It's getting damn cold here in Perth too VB...

One thing that can make a difference to temperature, but only if you have a bubbler, you can turn the system off at night leaving the water in the tank with a bubbler going. The water running through the grow beds at night loses heat but I doin't think this would make an enormous difference to your system with only the one bed.. Perhaps something to remember for the future if and when you get it into the shed with the growbeds outside.

Has anyone thought about using bath tubs as grow beds >?

I know that Frosty had planned on using bathtubs at one stage, but I think she may be on another design path now..... I reakon bathtubs would be great, I've just never actually seen anyone use them.....

Seems like a long time since I first raised this topic. I guess that is because it was a long time ago - yet the pond still just has duckweed in it, no fish. Hopefully that won't be the case for too much longer.

Today I picked up another pond. This one is a bit smaller. It is round, 110cm diameter and about 42cm deep. Reason I bought it is that I have figured that my existing pond will get pretty low after my 580 litre (Murray built) grow bed is full of water (probably take a couple of hundred litres of water). So I thought, how do I increase my capacity for the test setup but still use this pond. Answer, get another pond and join them with I pipe going between the drain holes. I will probably have fish in one and duckweed growing in the other. Alternativelly I may have a second batch of fish or red claw. When the grow bed floods, both ponds will drop by an equal amount, meaning that I will have more depth for my fish during this part of the cycle than I would otherwise have had.

Because my second one is smaller, it will not quite double my capacity, but it will certainly help.

The pump will be in only 1 of the ponds, but the flow of water from one to the other should be sufficient to ensure that both are filterred adequatelly. I may even have the water coming from one pond but returning to the other. Another thing I thought about doing was having a cut down blue barrell in between the ponds and connected to each. The pump would be in the barrell and would increase the capacity by a bit more again. May do this later on down the track. this would have the added attraction of keeping the pump away from the fish.

Editted to attach a diagram (pretty crap one at that).

really like the idea of 2 tanks linked together. Hoping to do the same thing seeing as my tank is a bit shallow. could put littlies in one tank and biggins in the other....

Nice one VB.. Have you worked out your total water volume in the fish tanks? You will then be able to get a good idea of whether your going to have enough volume for flooding the bed etc.. I started to work out the volume of the tank you have just mentioned, but couldn't remember the size of your original tank.... 3.16 x radius squared x height...

Hi Joel - Good to see you back on deck.

The calculation I use is diameter (in metres) x diameter (in metres) x depth (in metres) x 0.8.

Pond 1
1.15 x 1.15 x .45 x .8 = 476l

Pond 2
1.05 x 1.05 x .40 x .8 = 352l

Total = 828l

They are both a little smaller than I first thought - and this is having water almost to the top. I will put netting over top to stop fish from jumping out.

Now I just need to work out how much water will be in grow bed on flood part of cycle. Will have to do bucket test soon - but will first have to buy some gravel.

I reckon this should do me until I get a bigger tank - hopefully one of Murray's fibreglass 2,500l jobs. Chances are the fish will not be too big by then, so the depth will alllow them to survive - even if they are not as happy as in a deeper tank.

I am also seriously considerring just going continuous flow until I get a bigger tank. This solves the water depletion issue.

vb I bought a 10 litre bucket of gravel and it took nearly 4 litres of water to fill it Thought it would be more like 2 litres. Reckon continuous flow is the only way to go with shallow tanks Is the main advantage of flood and drain how evenly the bed gets the water as compared to continous flow??

Yes the problem is getting the gravel properly wet. IMHO needs more piping if using continuous flow. Also I don't know whether my little pump will pump enough to wet the gravel properly under continuous flow - and I don't really want to start using my sump pump until I move to my big tank.

Monya - what size and shape gravel did you use?

VB it was a 7 mm cracked style. Thought a cracked would displace more volume than round but will do the test again tomorrow as the gravel has settled a bit. Will post results. Also planning on trying a few different ones so will post those results too when I get around to it......

40% water does seem a bit high. May be the bucket maker has given you a bit more for your buck - and its not really a 10 lite bucket

Have purchased 10 bronze commets ($1.50 each - more than I would have liked to pay). Put 8 in the pond that pumps water through my small (40l) grow bed. This pond is coverred in duck weed and water is also a bit brown - so will probably never see them again unless they decide to float after Dying. The other 2 I put in the other pond. This pond has no pump or anything and I onlyhave about 15 cm of water in the bottom. It is starting to get a duckweed cover over the top. Will watch these 2 - as I can see them a bit. That pond is chocka full of mozzie wrigglers (the other one probably is too). So far they are not interested in them - but I think they are in shock.

I couldn't find plumbing needed to join the 2 ponds at B. Will have to go to a specialist irrigation joint I think .

Will use the golfish to cycle the system - though I expect I have some bacteria in there already - it has been running for a couple of months now with no fish, but I have been putting some seasol in now and again and thee would also be decaying duckweed and stuff in there.

Will not put silver perch in until it is properly cycled, I have joined the 2 ponds and possibly put my first Murray built grow-bed on. This is going to depend on how quickly I develop my welding skills.

VB, I will give you a couple of skin fittings tomorrow to join your two temp ponds together with a bit of pipe for the job to get you sorted for your temp system.
Murray