Backyard Aquaponics
A place to discuss aquaponics

Hi all, I've known about aquaponics for almost a year, but new to building a system. Do any of you guys know a basic guideline on how many litres per hour a pump has to pump?

Also, do any of you know how to make a bell syphon using a glass jar (so I can see if the suction's working etc).

You want to match the LPH, to how many liters your fish tank is. That is with head, not the number on the box. You can usually find data sheets on the specific pump you are considering. It will list the LPH for different head heights. As far as making a siphon bell out of a jar, it is just a matter of finding a wide enough mouthed jar, and silicon in a piece of PVC the same size to the mouth, and cutting crenialians in the bottom for water to flow through.

Thanks Ronmaggi, and I think my fish tank could get up to 200 L to house 3 goldfish and 2 of some sort of coldwater loach.

PS what do u think is the best (for it's value) media to grow the plants in? Is normal gravel that would normally be used at the bottom of fish tanks be a suitable media for the plants to grow in?

You will know if the suction is working. No need to see it to verify.

The aquarium gravel is too fine. You want something coarser.

So does the pump have to pump half, one, two or ten times the amount of litres (or gallons) of water in the fish tank every hour. So e.g. if the tank had 200 L, would the pump need to pump 100, 200, 400 or 2000 litres of water every hour?

You want at least one turnover of water per hour. If you are running continuously, your pump just needs to move that many liters in an hour, taking head into account. If you are running 15 min on 45 off, you need to move 4 times that volume.

Is running continuously but with bell siphons a good way to do it or is a timer better?

Initially I was going to go with a timer. But, with a timer, flow stops and timers add to cost to get one that can be programmed in short increments. I decided to go wit ha bell siphon so the pump can run all the time and it just drains when needed. I got mine to flood and drain 4 times per hour.

How much space do tilapia need per fish?

Tilapia like to be crammed together. That being said it is still important to stock according to biofilter, read growbed, volume.

So if I had a fish tank of 200 L, and 2 growbeds of 60 L each, and the fish tank 1 metre long, how many tilapia could live in there?

Forgive me for not being very metric savvy.

Oh sorry about that:

A tank of 52.8344 US gallons (200 L), one grow bed of 15.8503 (60 litres) and the fish tank being just over a yard long (1 metre), how many tilapia could be grown in there?

BTW I've changed it to only 1 grow bed (even though I've bought two) because of space issues.

so for your one growebed, you could grow out one fish to a little less than a pound
for every 100 gallons of growbed, you can (safely) grow out 20 to 25lbs of fish