Backyard Aquaponics
A place to discuss aquaponics

Hi there, I new. I have a large, about 1500 high rainwater tank in my backyard and I have been eyeing it off for Aquaponics for some time. I want to cut it in two using the bottem for the tank making it 900 deep. The other end i will use for grow bed. My querie is to do with pumps. Can I use a pump that is outside the tank and with a timer? Why does everyone seem to use submersable pumps. Also my tank (round) will be about 1800mm across the top and 900 deep. How many fish (Barramundi fingerlings) should I put in the tank?

Welcome to the addiction.

Well yes you can have the pump outside. In regards to why most use submersible pumps, I guess it is possibly because you do not need to plumb up the suction end as well. Furthermore you need to suck the fish crap from the bottom of the tank so you might need either to make a hole at the bottom of the tank or have a pump with a head suction to move the crap out... In addition, you don't really need too big a pump so generally a suitably sized pond pump should be sufficient.

The amount of fish you can keep in the tank is determined by the amount of filtration (growbed medium). It is generally recommended to have 20-25 fishes for every 500L of filtration. This is based on each fish growing out to approx. 500gms.

Recommend reading of the Basic Information and Useful Information section of the forum. Good luck.

Note that depending on the water temperatures, it may not be until end November/early December that barramundi can be kept outdoors without heating...

A few things

If your tank is poly - disregard. If its metal, it needs to be Aquaplated or you need a liner in it - stop it leeching nasties and killing stuff

Re the pump. I live rural and use these for the house/watering etc etc. 15 mins on/45 of should be fine but only certain external pumps are rated as continuous (incase you want to change to 24/7 flood and drain). To by a "cheap" ext pump will cost >$100 and you can get a fair sub pump for the same

g'day skipd, Ive got the same size tank as yours it's got a Aqua lined paint on the inside, when i first got the system cycled i had 10 Barra would have liked more but decided to take it easy first time round, have now got 40 Rainbows in it system is coping nice.
as for pumps have submersible pump $100 bucks bunnings 15min on 45 off
good luck

Cheers for the tips people,
With that metal tank leaching thing, would painting the inside of the tank with some sort of pond sealer be suitable? What paint to use?
The $100 bunnings submersable pump sounds good, havnt been there yet this weekend!
As for the fish, if still to cold for barra would trout be a better option? I dont really want to heat the tank.

Too late for trout now. It will be too hot before they grow out. Possibly start with a small batch of silver perch as your first run.

Sounds good, might be a way off until I get system up and running by the sounds of it. I guess I will just check out whats going at the time.
AP on, Skipd.

Patients is a good thing, you can always fishless cycle and keep the plants going till you get to the season you want to add fish. Trying to rush usually leads to stress and sometimes heartach.

This is my member system page, can I change its name, please.
And on to other news.
My water parameters have changed, YIPEE, at last.
Tested this afternoon and they are at 3pm,

Ammonia 0
Ph 7.6
Nitrite 1
Nitrate 7
Water temp 19.5 deg C.
Just wondering if I should start feeding again and how much?
30 Fishes average 100mm long in 1780 lt FT, 780 lt GB.
Ill be heading to BYAP on the weekend to get me some good feed.
Any advice would be greatly appreciated.

Anyone?

I am assuming Silver Perch?

Start of with a couple of handfulls of feed, give them 15 minutes and see if there is any left floating / or sunken on the bottom of the tank. Silvers will feed from the bottom, but if it is still there after that amount of time they probably wont. Goldfish are good for that

General rule of thumb, feed until they wont eat, 3 or 4 times a day and monitor the water.

Start off with 1 feed a day for a week, then up to 2, and so on.

15 SP, 7 Koi, 7 goldfish.
Cheers for the Rule of thumb OBO.
Will commence feeding tommorow.
Just before I stopped feeding about a week ago I threw in some brocoli and lettuce leaves. They got eaten up pretty quickly.
Should I put leaves in as well for them to munch on?

Not really any need to, Silvers are quite happy on tank wall algae.

ok, I guess it just complicates feeding regime.
Cheers OBO.

I recall on another thread that you are still trying to sort out your water turnover right? So yes, I would go slow on the feed. And since they are silvers there is really no rush to grow them out by the next change of season.