Backyard Aquaponics
A place to discuss aquaponics

well after countless hours of reading and research, a week of tinkering with junk laying round the backyard and an ebay blue barrel....i've done it.

now those fish that my sister left behind (in our pond) when she moved out are actually doing somthing USEFUL.

basicly i had a 120-150lt pond already established with a couple of aquatic plants
(lilly & papyrus)with 4X70mm goldies in it.

best part is the folks bought a decent pump for the pond a while back(better than a standard aquarium pump anyway) 1600L/hr so thats plenty for this initial setup altough i can c things getting out of hand quickly...(note to self must refrain from adding to much to this system)

so about 2 weeks ago i decided the best thing i could do b4 i had things up and running was throw in a few extra little guys, so i bought 6X30-40mm comets(coz they didnt have any chepies) thought $20 was a bit rough but it was them or nothing.....

now the blue barrel i bought was of the sealed variety so i decided to cut off the top at about the 1/4-1/3 level and use the small bit as a grow bed and have saved the big bit for a FUTURE project (know idea yet really) made a drain/overflow pipe & guard silly sticked it in, waited a day for it to dry well then filled it with media(i used quartz rock 3 different sizes, almost fist sized layer right on the bottom followed by a 40-50mm(depth) layer of 30-50mm rocks then filled the remainder of bed prob 70% or so with small quartz pebbles 6-12mm mixed with river pebbles of the same size.

cutting a long story short(way too late to still be up)plumbed the GB in and added some worm casts from my farm prob 1 good handfull spread out bout an inch or 2 under the top of gravel and some of the gunk from the bottom of the pond 2. planted some leftover seedlings i had germinated a week or 2 earlier and a few other bits mostly transplanted thinnings from regular ground crops all just to get an idea of how its all going so far(only been cycling the bed for 3 days at this stage) all seemed good all transplants plumped back up again fairly quickly.

patience with new ideas never been 1 of my strong points so naturally while waiting for bed to cycle PROPERLY i'm thinking of ways to add to the fledgling sys, BINGO the little light bulb above my head was lit and out comes the grinder and some scrap guttering from installing the bigger tanks i put in at xmas time. used a 3ft section of 2x4inch box down pipe cut small squares in it to hold small 3inch square pots suspended off the bottom of said box each pot its watered by a sprinkler riser nipple directly from a common 12mm poly pipe. this new section is higher than the GB, so i put in a tap on the GB to restrict flow giving me the extra pressure i needed to pump a continuous flow of water in to each of the 9 new mini pots which inturn gravity drain back to the GB followed by the pond. Pots now filled and cycling joy more waiting.....

so anyway up untill this point the sys has NEVER been tested not even the pond and its been there for at least 4 years......

so being as tight as i am(more about conserving than consuming) i make a few phone calls and find 1 of my mates has test kits and no fish anymore.....shame... so i borrowed his kits
PH Nitrate and Ammonia....and do a WATER test for the 1st time in my life.

now i'm a complete noob so i could be wrong, but i think i'm either damn lucky or i've nailed this startup (beginers luck i know).

10 fish being fed 3times a day for about 3mins each sitting for say a week...no real filtration...
add GB on Sat morning and start cycling, Mon morning add my new mini pot sys and start cycling.... tests happened at midday mon
RESULTS PH 7.6
Nitrate 0
Ammonia 0

my only concern is i dont have a nitride test kit
i would have thought i would have some nitrates at least.... being that the pond is quite an established eco sys prior to my playing with it.

the only logical thing i could come up with is my sys is working fine and the small amount of waste the 10 fish produce is being used up by existing pond plant life and the few measly seedlings i put in already.

my thoughts..
Bacteria must be present or the original fish would have died atleast a year ago!
all fish happy and feeding well many times a day

SO my solution to the little dilema as it was at midday i went shopping not for a nitride test kit as u may have thought... no i bought more fish 14 more to be exact prob about 40% extra biomass taking the total up to a stagering 24 lol.

what would be the MAX range for fish density in a 120-150L pond my GUESS is 50 would be high density 70 would be pushing the safe limits...

any and all thoughts comments and questions happily answered/explained

density assuming average size of say 40mm and thats being quite generous

Humm... where to start Mickey.... well welcome firstly...

Being an established pond, it's not surprising that your ammonia levels are zero... as you rightly say, the pond would be well and truely cycled with the original 4 fish and feed load...

And the water plants, especially the lillies, would be sucking up all nitrates available... lillies are heavy nitrate feeders... and I dare say the papyrus is thriving as well...

However, you have added a significant load to your small system since then... with the addition of another 20 (in total) new fish... 5 times more than you had before...

And you've increased your feed load by a corresponding 5 times more....

While the existing "cycled" pond was coping with the bio-filtration of your previous fish stock/feed load... and will help the new growbed and pots cycle much more quickly...

You really haven't added any where near 5 times as much bio-filtration... to match your increased stock/feed load....

And I'm fearful that your system is (at the very least) temporarily over-loaded and may prove to be under-filtered... it just hasn't shown in your test results as yet...

I would be testing again this morning, and evening... and would be prepared to stop feeding for a day or two... and/or if needed do a water change...

The aquatic plants probably coped with the "doubling" of the fish stock i the first week... but you've since doubled it again...

Go and test it again please...

We normally advise a stocking density of 3kg/100L... which in the case of your system (150L)...

Would be a maximum of 4.5kg of fish mass... given that they're goldies and comets... and not likely to grow much past 300-500gm... that's about 10 500gm fish ... max... or 20 at halve the size...

So I think you're maxed out as far as fish load goes in your small pond.... and that you may also need to provide some aeration for that number of fish...

Again, due to the nature of your fish, and low protein level of the feed... your filtration requirements are much smaller than what we would normally suggest... that is that you should have at least as much filtration capacity as you have tank/pond capacity... 150L

I'd consider using the remainder of the blue barrel as another growbed...

Secondly... you top mix of gravel is very fine... and might prove to be too fine... trapping fine sediments and clogging over time.... again the nature of your feed might mean that you'll get away with it... whack some compost worms into the growbed(s)...

Thirdly.... you'll probably find you over-head drippers will clog over time... unless pre-filtered...

will do another test in a few mins

thanks for the pointers rupert.......i can c this developing into a reall addiction...

all things u mentioned i am pretty much aware of so no real surprises which is nice

and adding more GB's is my goal..... so u suggest to have an equal amount of GB volume to water capacity?

thanks again

Mickey

just done new test exactly same as 24hrs ago
A 0
N 0
PH 7.6

equal media to fish tank is a good minimum, of course if you go with more grow beds you have to sort out some way to have more water to flood the beds without running the fish pond dry.

And Yes this is addicting. but at least you found a good support group

another trip to the aquarium

bought an airstone... borrowed air pump from friend whose fish all died

some floating pellets so i can vary their food every now and then have been using normal flakes so far

a few meters of air hose and a pack of blood worms for a weekly treat

spent ages looking round like u do...refrained from buying any more fish (not so easy) good thing they had run out of catfish coz i was thinking that maybe 5 of them would be good for stiring things up and cleaning a little what do u guys think??

Air stones good. Just keep up the testing.

I read above that you did not have a nitrite test kit?? Did you get one eventually? Hope you did and the N above is Nitrite. Nitrate is important but not critical to know if your plants are growing well. Nitrite on the other hand is toxic to fishes.

If you have not added salt into your water, I would suggest getting some salt (either sea salt or natural lake salts) in hand at least. So if you detect increased nitrite levels, you can salt the pond.