Backyard Aquaponics
A place to discuss aquaponics

I am building a aquaponic system for the first time and have a number of questions. I have a 1000L tank and two bath tubs filled with 10mm blue metal gravel. I have a pump that fills the baths in 2 minutes it takes about 15minute to empty the baths. I can only find a digital timer that can have 14 cycles so I have set it to 2minutes pumping every 2 hours. Will this be sufficient? If not can someone tell me where I can get a timer that can be set to pump 2minutes on 15minuts off repeated. I am thinking of growing Jade perch. How many would be a good number to stock?

My system is built beside a hill so I am gravity feeding back to the fish tank. I can add extra bath tubs and 1000L palicons to my system.

What problems arise by heavy rain on a system that is not covered?

Stewart,

if you have a pump that can be throttled back, you could do that to slow the flow. Alternatively, if you have a standpipe in the bath tubs, you could run the pump for 15 minutes with the excess flowing straight thru the standpipe so your bed doesn't overflow.
IMHO 2 minutes ebvery 2 hours is probably not enough, particluarly if your return water is your aeration too. Just a thought. Maybe with added aeration, the 2 minutes cycles would be not so bad. If you add more growbeds at the start, that would double the water turnover straight away, and have more space for vegies:)

I have the digital time you have, and it is very reliable and accurate. Mine is on for 12 minutes at a time, for 13 cycles with one 13 minute cycle once a day to fill em right up. It takes around one hour to drain fully, so my system sits idle for around 15 minutes between cycles.

How many Jades? Your maximum finished fish weight if you had twice the growbed medium to fish tank volume would be 60kg's so say 120 fish. If you had 1: 1 ratio, that would be 60 fish max. If you had only say 500 litres of growbeds for your 1000 litre tank, I would start with around 40 fish which would allow for a few deaths and hopefully leave you with about 30 plus fish. Just my thoughts.

As for heavy rain. A massive down pour may flood your system, so you could easily ready yourself with overflow lines etc, also, it would dilute the nutes a bit, but that isn't a major problem really.

Good luck!

Hi Stewart, good to see another newcomer to the AP fold

Steve, have you googled "chillingham" yet?

no why was i doing that again?

Thought you might like to know where it is - not in Vic tho (its where Stewart is from)

i got a digital timer on ebay that has 20 on/off cycles a day. Seems quite good.

I am guessing it's this one

If thats the one you want PM me and for $15 (inc post) I'll send you one

More detail for anyone that wants it....

Description: 7-day Digital Timer
8 ON/OFF per day, 56 ON/OFF per week
Min. setting time:1 Min., Max. setting time: 7 days
Summer/Winter time optional
Random funtion
AM/PM or 24 hours display
Rechargeable Ni-MH battery, reserving data for 2 years once power off

Checking with overseas but believe the specs quoted on eBay auction are wrong.

Have PM'ed Nick to confirm model he purchased

Another thing you can do is put in a couple of ball valves to throttle back and/or divert your water back into the tank. That will help in aereation, and slow the fill of your growbeds. People with much more experience than I can give you a better answer, but if you have it on for 15-30 min to fill, then the rest of the hour to drain, it should keep the plants and bacteria happy, but still allow oxygenation to the roots.

this is the item i won
http://cgi.ebay.com.au/ws/eBayISAPI.dll ... &rd=1&rd=1

sorry i threw out the packaging so cannot give you the item no.
but it definately has 20 on/offs per day.

Sorry I can not help more.

Hi Nick, I'm out of stock (have ordered some more) so I can't check.

My docos from Sansai are as quoted, however in response to a question from your seller they replied ...

"on the instructions it says 20 on/off settings per day, 140 on/off settings per week "

Could you check for me Nick.

I'll have stock hopefully by the weekend so I will post a definitive answer.

yeah that is what the instructions say. i got mine for $20 total including postage so if you could beat that price it could be a good seller

Pretty funny that the potage is $19 and the item is $1. Seems crazy