Backyard Aquaponics
A place to discuss aquaponics

I just move into a new apartment that has a great terrace with lots of room and potential. So I'm totally new at this, and learning as I go. Here are my current stats:

-existing koi pond, about 2500L, 36cm deep
-a pump that works, but I don't know anything else about it, except that it trips the breaker frequently. I will have an electrician come fix that soon, hopefully.
-8 mature koi, ~80 fry, 3-6cm in length
-full sun exposure on the pond for a good 6 hours each day, lots of algae in the pond
-frangipani tree nearby that drops blossoms and leaves, but I get my 5 year old to scoop them out and put them in the compost
-existing filter in a 5 gallon bucket; seems to do nothing at all.

I'm planning to buy this growbed on TaoBao (Chinese Amazon like website) https://world.taobao.com/item/36243374182.htm?spm=a312a.7700714.0.0.xnildC#detail
Which comes in two sizes: 120cm x 70cm (depth isn't listed, but I'll guesstimate 30cm) and 120cm x 180cm (same depth); which would give volumes of 252L and 648L respectively. From what I've read, my stock density should easily support the larger volume, or 2-3 of the smaller ones. Does that seem right?

My next issue is sourcing grow bed media. Since I am in China but don't speak Chinese, I will do this with some combination of photos and numbers and hand signs...but since it is sold by weight, and I only know the volume I need, I was hoping someone here has a handy chart that lists various types of grow bed media by volume and weight. Anyone?? Next step will be heading down to the landscaping depot with a measuring cup and a kitchen scale

Also, how do I know what the [volume/time] of water my pump pumps? This will factor into how I run my cycles, right?

Any and all insight is greatly appreciated! Xoxoxo

my early AP ventures were primarily as filters for goldfish ponds and yep they work well.
200L of plastic container with media worked much better than a $200 filter for a 1000L pond.

the $200 filter needed regular flushing and a bigger pump than I wanted and was a PITA.
with AP you get the bio-filter for ammonia conversion thrown in for free, and a smaller pump is OK

As filters for koi/goldfish you can get away with a bit less than food fish, particuarly if you don't feed every day.

Work best if you run as a constant flood or timer F&D (with long pump times) as you want filtering.
You can easily put a tap in bottom of grow bed to drain out solids and use for compost, other plant watering etc.
then get rid of any other filter.

But at end of day being on during daylight hours on and a break overnight with just an hour every now and again will work OK. You dont need to run 24/7. On a AP system I find 30min-30min, or 1 hr/1hr works fine,
or else you can run for longer periods (don't want less than 30-30 IMO, more = more filtering).

[edit] you can run with pond plants or reeds in your pond as well. They will help use up the nitrates....

your pump is not really that important for your situation - 3000 LPH up to 6000 LPH would be fine.
relatively inexpensive and should be able to use something under 100 Watts.

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2500L will easily support a lot of grow bed. Make sure whatever you buy containers/tubs as deep as you can get.
350mm best, 400mm even better.

120cm x 180cm x 30cm = ~650L, so you will get around 500 litres of wet media.
You could easily have 2, 3 or even 4 of these if you are stocking your koi up.

you probably have to check the specific density of your media (as you suggest).
usually rock product is about 2+ kg/L so 100L would be about 200kg. (a ton would do approx. 500L)
clay and light media is 1-1.5 kg/L expanded clay is around 0.7 kg/L

[edit] the ones on website look a bit shallow, but maybe just photos. You would need to fill all the way to top.
however I would look for something deeper, greater depth = better bio-filtering as above.
maybe look for some large rectangular tubs or even vegetable pallet crates

Holy crap a metric ton seems like a lot, but I guess that makes sense. I'm having someone build the supports for me, so are there any guidelines on how to build a support strong enough to support a ton of rocks plus some water?

I will have to figure out how to message the seller on TaoBao and find out the depth, clearly the bins are meant for aquaponics (they display a CHIFT PIST system in use, if I am not mistaken) but what you said about the depth-->filtration makes sense too, I will keep that in mind.

The constant flood system seems simplest and easiest to assemble, which is great, but I'm concerned about the electricity required...would running a pump constantly mean a massive electricity bill? Since Macau is muggy as s**t and I have fair Canadian sensibilities I'm already running air conditioning and dehumidifies in my home pretty much 24/7.

Are there any diagrams that you know of that show the tap in the bottom of the grow bed in a constant flood system? I'm not quite understanding how that would filter out solids? Or do you mean like if it gets really mucky?

Also (forgive me) can you explain to me what you mean by 500L of wet media in a 650L grow bed? Does that just refer to the rocks, water and plant material, collectively? Or is there some other element I'm missing here?

Thanks for your help, mate!

Holy crap a metric ton seems like a lot, but I guess that makes sense. I'm having someone build the supports for me, so are there any guidelines on how to build a support strong enough to support a ton of rocks plus some water?

The BYAP grow beds take about 10-15 50L bags of expanded clay......
Yep that is an issue if you use granite (blue metal) or iron stone etc.
Is why many prefer to use expanded clay (one of various reasons)

most reasonable steel will be OK. 32+mm NB galv pipe or 32x3mm to 50x50mm would be heaps.
Take a look at the BYAP courtyard systems for some ideas and pics.... http://backyardaquaponicsshop.com/produ ... c-systems/

I will have to figure out how to message the seller on TaoBao and find out the depth, clearly the bins are meant for aquaponics (they display a CHIFT PIST system in use, if I am not mistaken) but what you said about the depth-->filtration makes sense too, I will keep that in mind.

it is an issue with many "commercial" products. They look a bit like a copy of the BYAP style ones so maybe you will get lucky. I have brought 0.6 x 1.5 x 0.4 deep rectangular tubs and they are much better (or get bit higher and chop down to size if you like).

The constant flood system seems simplest and easiest to assemble, which is great, but I'm concerned about the electricity required...would running a pump constantly mean a massive electricity bill? Since Macau is muggy as s**t and I have fair Canadian sensibilities I'm already running air conditioning and dehumidifies in my home pretty much 24/7.
yep. Few who know would say to go that path, definitely don't want siphons. If you put on timer you can get down to 50% use quite easily and power cuts are not really an issue. You should be able to get away with something less than 100 watts so that is like running a couple of old style light globes....

Are there any diagrams that you know of that show the tap in the bottom of the grow bed in a constant flood system? I'm not quite understanding how that would filter out solids? Or do you mean like if it gets really mucky?

will have a look if I have a photo. I put them in all of mine. Basically you get a build up and once a week /few weeks or whatever you just open up and drain the bed. Makes great pot plant and fruit tree watering. Work great on your Chinese New Year cumquat/mandarin trees

Also (forgive me) can you explain to me what you mean by 500L of wet media in a 650L grow bed? Does that just refer to the rocks, water and plant material, collectively? Or is there some other element I'm missing here?

filtering is only the wet portion of your media. The water level needs to be about 5-10cm (2-4 inches) below the surface. So not all of your media is actually a biofilter - only the total bit (roots, media and water) with water in it. So the water volume will be about 0.4 of that (and media/solids about 0.6)

BTW - you really want to maximise media as a DWC wont provide any/much filtering.

most reasonable steel will be OK. 32+mm NB galv pipe or 32x3mm to 50x50mm would be heaps.
Take a look at the BYAP courtyard systems for some ideas and pics.... http://backyardaquaponicsshop.com/produ ... c-systems/

p.s. Colum Black-Byron has a post talking about home made stands.
here....http://backyardaquaponics.com/forum/vie ... bed+stands
(those are better GB tubs IMO)
here.... http://backyardaquaponics.com/forum/vie ... =1&t=21207
and here for the blow by blow complete with goldfish porn... http://backyardaquaponics.com/forum/vie ... 18&t=19967

He uses blue metal (granite rock product)

the other option is to use cinder blocks/cement blocks with a frame on top.