Backyard Aquaponics
A place to discuss aquaponics

Hi folks;

Bright eyed, totally keen Newby from Perth WA saying hello to everyone.

Been reading through the forum (and Joel’s book) & got a question of what direction I should take.

The question:
I have acquired an old water tank cut in half (about 1.8 x 1m … 3000lts) that I thought would be an ideal fish tank.
I was planning (for a trial) to use just one growth bed (which I have yet to build) of 6’ x 2.5’ ft. Then build more when I get the experience & have it growing nice - until I read about ratios.
Is the size of this tank over kill? Should I use a smaller tank, (I have 2 - 44 gallon drums that could split open) That would give me either 200 or 400 litres. Should I go with a small tank and transfer to the bigger tank when needed or stick with the big tank.

Thanks guys
MajorTypo

Can't wait of growing & eating fresh “clean” veges.

Welcome to the forum MajorTypo....

Interesting that you mix imperial and metric measurements.... gives us a clue to your age perhaps

The actual volume of your tank is closer to 2540 ltr... call it 2500ltr or less as you wont want to fill it to the brim anyway...

By my calculations your growbed works out at about just over half your fish tank volume approx 1400ltr.....

The minimum ratio of fish tank volume : growbed volume would be considered to be 1:1 ... so you're a little short of the optimum growbed volume....

Adding the other barrels would help, although you may have to seal them if they're steel drums....

Or you could reduce the actual volume of the fish tank by merely filling it less... say 2/3 rds full...... and stocking lightly until you obtain more growbed capacity.

I think starting with the biggest tank you can is a good idea as the capacity effectively provides a "buffer" against inexperience during the learning curve.

A small system is OK.... but needs to be stocked correspondingly and the margin for error and time window available to react to pH/nitite spikes is severly reduced directly to the smaller volume.

Don't be daunted though MajorTypo.... go with your grandest ideas and designs.... post them up and we'll all try/find ways to help you make it happen....

Hello and Welcome

What would be the depth of the growbed?

I would also go with a small fis density in a big fish tank, it would help you finding a way not using a sump tank which is used in most cases.
The amount of water pumped to feed the growbed during a flood phase of the growbed would not impact much the water height in the tank.

If your growbed is 1 ft deep, (based on 6 ft x 2.5 ft x 1 ft) the total GB volume is 400 L, then the total fish weight in system musn't exceed 11 kg, to stay in the limits of the ratios. It would still make a nice amount to play with for a start.

Hope this helps, have fun and welcome again to AP madness.

I actualy disagree with one statement rupert makes about MINIMUM ratios. I beleive that ratios are completely flexible down to the fact you could have a margarine container full of gravel filtering a 5000 litre tank if all you had in there was a guppy. I know I know I am being a bit facetious, but you hopefully get my point.

IMHO Start with the largest volume of water you can. Add a small number of fish and monitor your ammonia and nitrite levels closely for the first month or so. Get it started ASAP because if you wait until winter, waiting for the system to cycle will be much longer than if you hop into it now.

As your fish get bigger, you may need to add more gorwbeds, in which case you will be completely addicted and possibly remorgaging your house and kids in order to fulfill AP dreams of world domination by fish and veg

Have fun!

Another thing MT, Joels verandah system is running about 15kg's of fish (correct me if I have misquoted EB) in 4500 litres with one growbed of 1.2m diameter 30 cm's deep. All is good. Remembering this is a VERY WELL ESTABLISHED SYSTEM

Welcome, MajorTypo, to the fast-growing fish-growing Perth mob. You're a little far away, but feel free to come and take a look at my swimming pool if you like.

Welcome, MajorTypo, to the fast-growing fish-growing Perth mob. You're a little far away, but feel free to come and take a look at my swimming pool if you like.

Thanks for the info everybody – ok go with big, I like that - as it seems nicer for the fish.

One thing I trying to get my head around.

If I use a big tank with little amounts of fish (to be equal to my small GB). When the fishes do their thingies (IE make ammonia) wouldn’t this get diluted with the greater amount of water available. The GB will hold only so much water (the rest runs off no matter how big the pump is) so would the plant have less “food” and not grow as good as they could?

Also Pumps:
Looking around so far I’ve found that most 3000~4000 Lt pumps use about 100w compared to a 1400Lt pump that uses about 24w. Thinking - if I buy 2 x 1400Lt pumps (and use in tandem) if one dies I’ll still have enough to keep everything alive & use half the power to boot, and at a similar cost. Anyone know if the SunSun HQB-2000 are any good?

Major.

PS right about the age: I remember buying petrol for my bushbike as a kid for 35c a gallon & driving at a top speed of only 65 miles an hour instead of 70.

From my experience, either build a small test setup first and make cheap small mistakes, or visit as many AP'ers as possible and read heaps before you start. Big system uses big parts and big labour which means big $ for mistakes.
If i dont make any mistakes, my new 4000lt system will cost as much as my first 800 lt system because i redid almost everything at one stage or another throught inexperience and ignorance.

Im in hamlton hill, if you want to check mine out

show me yours I'll show you mine duckpond

I agree with Monya the larger water mass the less likeley it will jump around See my system [food & fish in the members section] it runs up to 3 pumps at different times to do different things Also start with a few goldfish they are hardy my original ones are now 8 in long then when you get up and running add more fish then as they grow more grow beds you will have plenty of time

Major Typo,
I started my BYAP system with a 200 L drum with the top cut out, servicing 4, half 200s as GB1 and 5 comets as my fish.
I expanded to having a 1000L FY, and added another 3 half 200s as GB2.
My 5KL tank was finally put in place and filled, making my 1KL into the sump and I added 10 Tilapia (150 - 200 mm long) into the big FT.
I have since added another 3 half 200s ad GB3.
I have a lot of growth and plenty of tomatoes, silverbeet, beans, rhubarb, beetroot, sweet potato, and onions growing (other veggies also, but can;t recall ATM.)
Feel free to call in when you come to look at Adrian's swimming pool. I am in Bedfordale also.

Tony

Hi folks;

Well having different people saying different things is all part of the fun I guess.
Hey you Bedfordale guys I’d love to pop over for a look see. Can you send me a msg somehow where you live. By the way (everyone else) these guys live in one of the most beautiful areas of Perth, up in the hills, heaps of citrus orchards close by, nice valleys (lucky guys).

MajorTypo

We're not really saying things that differently MT....

My suggested minimum 1:1 ratio probably should have been expressed as an "minimum" ratio in a stable system stocked at 3kg/100ltr...

Monya is right in that you can have way less, or more than that.... on the proviso that you stock your fish numbers accordingly.... and understand the variables involved

Yep, you could start off with a small number of fish and a small(er) volume of growbed... and increase both correspondaingly as the system and your knowlege increase.

As someone "new" to AP, I thought it best to err on the side of caution and suggest a minimum ratio... until you were more conversant with the interaction between fish load, water volume, water management etc.

We all basically agree that the larger the tank volume, the larger the margin in relation to ease of water management.... start with a small number of fish and test and observe.... add onto the system as your knowledge increases...




And Duckpond makes some relevant points....

It's not uncommon for people in their eagerness to jump into building a system and end up overstocking with fish... without perhaps having fully read and/or understood much of information available on the forum....

It's a learning curve.... and it doesn't stop even when a system is running smoothly.... coz that when we usually start changing things and/or experimenting

But that's the beauty of this forum, we all learn from one another and everyone is here to help

Thanks everyone for the info.

Well I’ve moved from phase research to doing – dug in my fish tank a third & will be making my GB tomorrow. Pump is on order, so things are on the move
Thinking ahead … water:
As I don’t have rain, fresh or bore water, it has been suggested that I simply run tap water through a drinking-water filter. Are there any problems with this?

MajorT