Backyard Aquaponics
A place to discuss aquaponics

I'd say that's a good guess. I had a kokopu jump the tank and the cat took it to it's bowl, (very domesticated ex feral it is) only a gentle bite to carry it, wee pinprick bites, back in the tank and away it swam, week later, dead fish with twin sores.

thats because cat mouths are just about the dirtiest thing you can get bitten by. It does not matter how small the bite wound an infection will definately set in.

Yeah, I'm sure it was another fish as no others in the tank had/have sores. I still have to sort it's small spot ouit, but the treally furry side is completely healed. It may be overcapitalising but it was good fun and rewarding all the same.

I just fed the fish and boy are they growing. Big ones now at around the 200mm mark, some still half that lenght and a quarter their weight. The big ones look magnificent, getting quite deep behind their head and fat too.

I know it is hard to keep the water warm, but if you can keep it above 20 deg, I would reccommend giving barra a go.

Hey Mon, how are you keeping the water warm??
Will you be able to keep it warm enough all winter??

Hi troutman

1) i pump water with a 50 watt pump from the fish tank through 100 metres of black painted BEVA tube on the roof of my carport. It's very effective. Today my temp rose from 21 to 24.4.Outside temp mid 20's and sunny. In the morning it should be around the 22.5 mark, will be 25 by tomorrow night and so forth. Only problem is when I have cloudy days in a row, takes a good day or 2 to get it back up again, but otherwise it is brilliant. Long term, the same system with a heat exchanger would be good, as the biofilm build up in the pipe will eventually cause problems I think.

2) I don't think so, but I am confident to be eating some before winter and nursing the others thru but generally eating them as fast as we can LOL. But if we have a sunny winter I will be confident to keep it just okay, and my greenhouse will get lots of sun when the leaves drop off the trees, and I have lots of thermal mass in around 3 cubic metres of gravel in my system and a total of 4500 litres of water, so I am looking forward to a successful winter fingers crossed. All new from here.

Hi Stu,

When it comes time to clean out that BEVA tube that you're using for a heat exchanger, you can use the detergent that they use to clean beer lines in pubs.....it will shift your bio-film in short order. It certainly moves the grime that builds up in beer lines.

Of course, I'd be ensuring that the detergent gets no where near your fish tank.....and flush your lines with plenty of fresh water (just like they do with beer lines).

Do a Google on "solar ponds". Basically, they are shallow ponds containing a very saline solution. The effect of the ponds is that they heat up to quite a high temperature.

If you were to place your coil of beer line in the pond, you might be able to cost effectively achieve the sort of winter temperature that you'll need to keep your Barra growing at optimum rates.

You might need to fiddle with your flow rates to ensure that things didn't get too hot.

Might be worth a look anyway.

Gary

Okay, I have used that stuff a lot, and yes, it sure cleans it up. What I have been doing is letting the pipes get quite hot once a fortnight or so, and flush with a hose attached to the garden tap with the outlet going into a bucket. Getting it all quite hot loosens the film and it doesn't require any detergents. Long term I am not sure if it is viable though.

I would like if you can do a diagram of the shallow pond idea with flow direction etc for me, I am a bit confused.

hey, isn't the avtive ingredient of the beer line cleaner sodium hydroxide? (caustic soda?)

If i'm thinking of the right stuff, then you'd be better off buying some from the super market and mixing it up (carefully, no one wants a blind AP'er that would be just cruel!)

it neutralises back out to water and salt if a weak solution of hydrochloric acid is mixed with it after. vinegar will also neutralise it. no nastie residues for fish.

Steve

make sure you don't use one with sodium metabisulphate in it. Very bad stuff.

Gary, I suppose you could trial the idea (shallow solar ponds) but I have only heard/seen large ponds used in this fashion and so never put my mind along those lines.....bit hot atm (for Janet to get her money) to work on heating the tank....must look further into it

Found this on the RMIT site - the operative words are "several metres deep"

Gary - I have been considering building a solar pond to use for my AP heating. Want to make sure my area is fenced off and inaccesible to the kids first cause I don't want to cook them. Reckon someone should give it a go, have definitelly seen stuff on the net where schools have built quite small ones in science experiments and stuff.

sounnds fabulus, get a digger you;re laughing

les, got a link?

how does the salinity increase with depth???

i want to know how it works! interesting