Backyard Aquaponics
A place to discuss aquaponics

Hi All
Any advice or comments on this following description and photos of my preliminary setup would be very much welcome and appreciated

I have a 18,000 (guesstimate) liter swimming pool I cant use due to council regulations. Every time it rains the pool turns into a mosquito swamp. The layout of the pool pump is such that there is always 10cm of water in the bottom.
About a month ago I turned off the drain pipe and let it fill with rain water, currently it is about a third full.
I have now installed a solar powered pump that pumps water through a set of hydroponic beds in which I have planted several seed varieties and some taro bulbs. I also have 6 small water chestnut plants in the pool and some other aquatic plants on order. I have some papyrus seeds but I suspect it's a bit late in the year for them to strike. It's mid autumn here, not that winters are severe here, No frost
The pool is full of life, algae, water boatman, back swimmers and mosquito larvae and pond skaters on the surface. A few weeks back I put in 6 fresh water muscles and the water clarity has slowly increased. Yes I do need more but the first 6 were a test. The pool is fill of rotting organics from leaves and palm fronds that have fallen into the pool over the last 6 months. .

Last week I released 5 Silver perch 3cm fingerlings and 30 glass shrimps. None of the fish have floated to the surface so I am hoping they are still alive in there. I can only see about 10cm below the surface (1cm before the muscles) I know at least some of the shrimp have survived because I inadvertently caught one in a bucket when I was testing the coarse filter and feeds to the beds. I have also dumped a few dozen half bricks into the pool, the type with holes. I figure the shrimp will need to hide as the perch get bigger
The current pump only runs when there is sun on the panels and the pool is quite shaded. I placed panels around so one is always in the sun. The panels are small 10w-20w but so is the pump, with a 10w panel in full sun the flow rate is probably some like 20 litre a minute. The pump came with a 20w panel and I happen to have 3 10w panels on hand. The pump is 24v which is more than the open circuit voltage of the panels , cheap and nasty setup that;s how it came I just added panels to deal with shading
I have ordered the parts to put in a second pump that will also be on solar with bigger panels. I am going to wire it up to a solar charged battery and have it run when the direct feed solar pump is not running. I am using solar because I don't want 240v near the pool. It's not that I dont trust mains powered pumps, but I would need to use a extension cord.
I feed the water to a filter pot with layers of gravel and sand, I am going to setup the second pump to feed through a second filter pot this one will have 3kg of activated carbon in between the gravel and sand. The feed into the pot tees off the hydro beds,

I have a ph meter, tds meter and some test kits on order as well as potassium carbonate in case I need to increase the ph. If I need to lower it I figure vinegar would do the trick (after calculating the required amount and testing on a small scale).

I just ordered 20 more silver perch fingerlings am I being too hasty?
Part of what me made me order the second batch of perch is the seasonal availability of fingerlings and there seems to have been a run of late in the stores on any form of home food production.



I added the little floating fountains when I added the muscles.
The pool is currently about a meter depth at the far end
The green pots also drain into the pool, The green pots are a mixture of clay balls and perlite, with the perlite as a layer between two layers of clay balls. The center pot is a mixture of gravel and sand topped with clay balls. I am yet to plant this one out but it will be lettuce as I want something with a shallow root and not some thing that is going to grow roots down to the level of the discharge holes
The second pump is going in the near end where there are steps so the water cascades into the pool across the steps to increase oxygenation.

Close up on the beds, note this is prior to adding clay balls to the center pot. That black is not dirt, but a perlite plus something mix. two are without this stuff. The black stuff water logs the beds so I may change it out if I cant find something that I can eat that likes to be water logged. The flow into each of the green pots is a trickle

the float is keeping the pump close to the surface and off the bottom.
I have drilled holes close to the top on the center pot so it drain holes get blocked the clay balls wont float over the top.

Thanks for reading this far.
Cheers
James

Hey cool start. You'll have great fun seeing the ecosystem evolve. For low power input, search airlift pump, best way to aerate, no pumps to break with blocking. If you don't need to lift the water very far also best way to pump water. My testing I have done with 90mm pvc, 80l/min aerator (36watt) is a lift of around 60cm, air is injected at 1.7m deep. So you could get a lift of maybe 20cm, with smaller pump and pvc? The flow rate is quite astounding. Haven't recorded yet..

Hi and welcome to the forum

Unused Pools are perfect for a decent size fish production system

A couple of thoughts for you to ponder

You will need to cover the pool about 90% (Restrict sunlight) or the Algae will consume all your nutrients , Silvers will eat some of the algae .

Over time you will get a build up of fish waste on the bottom that you will need to find a way to deal with.

You have heaps of surface area in the pool for bacteria to colonise so you will have no problem with those fish numbers for now .

yo can make a huge system with that pool. the clue is to internalize, realize, that in aquaponics you dont need huge amounts of ppms like in hydro, its a complete nature system where balance of nutrients and quality of water for the fish to be healthy and happy is more important than quantity.
You can fill up the pool to its maximum capacity regardless the amount of fish. You should start with small amount of fish, then, when everything is working as you desire, you can start adding more fish because if not, you may end with more solids that your system can manage and that will be a complete failure.
work on paper, what amount of food you want, that number will tell you the space you need for raft and the amount of fish you need. Once you have calculated the amount of fish you need, then you can calculate for media bed size. I recommend you that build two media bed of the size you need. for example, if you need a 4'x 4' media bed (14"high with 12" of media is the standard for everything to work properly)
then you should build two media beds of 4x4, that way, when you need to provide maintenance to one, you can shut down that one, and the other one will be continue filtrating the system.
for back yard, a media bed of the right size is the ideal filtration system because all you have to do is feed the fish. in a media bed of the right size, nature will work its magic of mineralization, nitrification and filtration, without the need for man intervention.

read all pdf in this page, slow, the idea is to learn and understand the whys
https://www.aquaponic.com.au/calculators.htm

then play with the calculator so you can know the size of the media bed.
then build the media bed, with a raft. play with it. once you dial it and optimize it. build a 2nd media bed with its raft, identical to the first optimized system.
that way when you need to do maintenance to one, the other one will continue working.
also, you can grow greens in one side, fruits in the 2nd one. so you can add fruit nutrientes directly to the 2nd system

What's the surface area of your pool? You can figure a rough idea of your stocking levels based on the surface area of the water and the final grow out size of your fish. Pumping allows you to increase the fish load, the more you pump the more fish you can have (as long as the pumps are reliable and you have adequate biofiltration) because there is better aeration. I think you have adequate surface area and biofiltration for your current fish load - you should be fine with 25 Silver Perch.

You need to be a bit careful about all the organic matter falling into the pond since it will use oxygen as it decays. The algae will produce oxygen during the day and consume it at night.

Do a search for "swimming pool" here on BYAP and you should find some other examples of pools - might give you some good ideas. Here's a short thread on one with a few good pics - http://www.backyardaquaponics.com/forum/viewtopic.php?f=1&t=26796

Thank you for the advice and encouragement.


I will cover the sunnier sections of the pool with floating solar panels and gardens. The need to cover and the need to find a place for panels almost perfectly matched here.

I intend to let the pool fill to the skimmer box. This will happen gradually from rain.

When the water level rises the heavy filter beds (black pot in the photo) of which there are now 3 will become water chestnut beds. I will raise the dutch buckets and build new larger filter beds placed on the edge of the pool.

I have built a low power air lift fountain that splashes in front of a sand bed, this runs in the evening.

Based on the spreadsheet I have enough pumping capacity though need more filter beds. The spreadsheet doesn't scale well as some output values are ##### due to the magnitude of the numbers being in excess of the space in the cell. The spreadsheet is primarily for tanks and not 18000 litre pools

I have put in duck weed. No I hear you all shout. I have a few dozen seedlings in the beds, it is going to be some time before these plants are established. Due to a large amount organic matter in the pool there is if anything an excess of nutrients. I will harvest the duck week into the compost heap. I realise it is there for good and a weekly harvest of fresh mulch will be a summer thing. I have a large dirt garden as well.

Leaf litter falling into the pool is not something I can stop, I'd rather find a use than a task. Provided I can keep the oxygen levels up in the evening it will just become another input to the grow beds (and duck weed). Most leaves in the pool are rosewood a rather low gum gumtree. If I start to get foam I will remove though no foam at this stage with over a years worth of leaf litter in the pool. I had been pumping out accumulated rain water every month or so. During the Sydney bush fires I kept 60cm of water in the pool, this is the seed water for what is currently in the pool. Another 30cm has been added in rain fall since I shut the valve.

I dont plan feeding the 25 fish until some time in early summer. There is a myriad of aquatic insects as well as algae, shrimps and duck weed for them to eat. I figure when the pond skater population crashes it will be time to feed the fish.


I have have two pumps (new) they are running only a few hours a day. One filter pot with layers of gravel, activated carbon and pool sand is run for 2 hrs after sunset, this currently has no plants because I am using it to lift the oxygen levels after sunset instead of running it during the day. The other pump is run intermittently through out the day for a total of about 2 hrs. This is the current limit of my power budget I have more solar equipment on order. I will us an arduino or two to better manage the system and the power budget as well the evening oxygenation runs


My plan is to scale to met the demands of the fish as they grow.