Backyard Aquaponics
A place to discuss aquaponics

Sump tank is mostly buried and is located under the growbed.

The fish tank is on the right of picture(cladded in corrugated iron), Grow bed, sump and fish tank are all insulated and lined.

I knew i was overstocked with just one growbed, but i thought i'd have the other growbeds up and running by now. Other things have taken priority lately.

I'm picking up 4 IBCs the weekend after next. Best thing is that they are free.

Quick plant update.

Growing well.


Started a small duckweed tub last week. Has at least doubled in size. The Goldfish in the 'wheelie bin' setup love it.

Test results from the 26th November 2013

Temp 23 Degrees Celsius
Dissolved Oxygen 7.54mg/L
pH 6.1
Conductivity 1635us
Ammonia 2.0ppm
Nitrites 0.5ppm
Nitrates 120+ppm

This pH is too low, yes?

How to lower it? Place shell grit in onion bag in FT or under outlet to growbeds?

If everything goes to plan, I should have some more grow beds online this weekend? This will help a huge amount.

Duckweed growth after 3 Days!

23rd November pic.


Crazy plant growth!! Only been 7 days since last pic.


Picked up 4 more 'free' IBCs today. Going to use 2 for holding rainwater for water changes and top ups and watering the lawn. Cut 1 up for 2 more growbeds, and use the last one for another fish tank, maybe?

System is going well Sam! Going to make a decent size system in no time!

Indeed, very good growth in the past weeks. Keep it coming!
I really want to see how you expand it, congratulations it seems you are making a very nice build for a very low budget.

Indeed, very good growth in the past weeks. Keep it coming!
I really want to see how you expand it, congratulations it seems you are making a very nice build for a very low budget.

One of my yabbies had babies. YAY! And another has eggs.

I'm thinking of adding another FT to the system, plus more growbeds. Run one FT all year round with Silver Perch and the other during winter with trout, so over summer one tank would have no fish in it. What problems could i encounter in doing this? Pumping fish waste from one FT to the other a problem?

I would rather not run another pump if i can avoid it, by adding another separate system. I bought an oversized pump to begin with, with the plan to expand. 7000lt/h sump pump, with float switch.

Could i link the FTs together via a SLO? Say pump from sump to FT1, FT1 overflows via SLO to FT2, FT2 overflows via SLO to GBs, back to sump.

Or pump from sump to FT1 and 2, each has their own SLO to GBs, back to sump.

I have a 600lt sump, would this be sufficient for x4 300lt GBs, or shall i add another sump? Then how do i link the sumps when one is already partially buried? Hmmm. Could link them halfway down the sides, so i don't have to dig it up.

Or should i not bother adding another FT, but rather just add more growbeds? And stock to growbed volume.

I like the idea of 2 FTs, added benefit of more total water volume. Might help with temperature and nutrient load swings. But if it's just too hard i'll scrap the idea of another FT.

Thanks in advance.

I don't think adding another FT should be very complicated. IMO the best way to go for your scenario is to use just one pump, yours seems good enough, and it would be easier to pump from sump to FT1 and FT2 and then to growbeds The problem would be the perch/trout you are trying to keep; maintaining stock density for appropriate plant growth when one of the fish tanks has no fish(maybe you could keep perch in both Fish tanks in hot seasons and trout in both in cold season? I'd search for similar approaches or wait for the answer of a more experienced member)

A 600l sump should work for a maximum of around 1200l of growbed more or less, depending of type of media you use. You could fill a 20 l bucket with your gravel and then measure how much water fits for a more accurate ratio.

Also, as you said, you can expand the system by adding growbeds first. Remember you can have as much as 2 l of growbed for each litre of FT in heavily stocked systems. I suspect your fish tank could handle heavier stocking if you had more GB, so yes, that might be the more sensible first step, but.... you DO have 3 other IBC's... ready to be used....

Don't join the tanks... if you don't want two separate systems... and only one pump...

Then as you suggested... just split the pump flow from the sump to both tanks...

And have each tank (separate) SLO flow to the grow beds... draining to a common sump...

One fish tank will only remain empty for the first season...

ie Perch in tank 1 for summer... you could split between the two tanks.. but I wouldn't bother... as the nutrient water will be supplying both tanks.. and both grow bed runs anyway...

Trout in tank 2 for winter... perch in tank 1 for winter...

Introduce small Perch fingerlings to tank 2 during the next summer... after the trout harvest...

Combine the fingerlings from tank 2.. to tank 1 at the end of summer/autumn... and replace with trout in tank 2...

(you should be starting to harvest/eat your original Perch from tank 1 by that time... but bare in mind the overall biomass...)

Thanks, this is what I was leaning to. Seems the 'best' way to do it.

Hey Sam be interested to know how u fixed the panel work onto your grow bed. That a tidy finish. Was thinking of doing along the same lines but with corrugated iron. And possibly some wood edging. It any new pics of your add on's you have done. How are all the fish coping???


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Sheepy, I attached horizontal bits of decking board to the IBC frame first, then screwed the decking boards to these.

As you can see in this photo.


We harvested 5 trout the other day. Nothing big, around 250-300g. Baked them whole with olive oil, spring onion, garlic, lemon, cherry tomatos, salt and pepper. "These trout are awesome" said my son.



Fish are doing fine, levels have settled a little.

Will get some pics of add ons soon, when i finally do them. I have been pretty slack lately.

Was going to do them this weekend, but went fishing all yesterday, and today was a writeoff as i was recovering.

I did catch a nice Callop, at around 50cm, and a 40cm Silver Perch, and i lost count of the redfin caught! But it was plenty.