Backyard Aquaponics
A place to discuss aquaponics

the fish are off their feed. Normally when i walk to the tank in the morning the fish are near the surface and waiting for me. I ran out of pellets 2 weeks ago so i have been feeding the silvers a varied selection of food. Marinara mix, kangaroo meat and oxheart along with all manner of insects and a daily dose of about a salad bowl of leb cress. Yesterday in their afternoon feed i gave them 375 gms of finely chopped oxheart which they smashed pretty quickly, today they are not interested at all
parameters
100 to 150 silvers average 250 mm or approx 200 grams
ammo 1
nitrite 0.25
ph 7.4
nitrate 60
water temp 22 deg c
ambient temp 19 deg c
weather overcast and still
I added about a kilo of salt to my 2250 ltr tank at 9 am today.
No sign of flashing or peculier behaviour
if i have 100 silvers at 200 grm thats a 20kg live weight. 5% is approx 1kg of feed. There is no way i have been feeding them that much.
I have had an order in for pellets from ridley since mid feb, now i have gone to growbest and am expecting a 20kg bag of native 5 mm grow out in the next day.

Any suggestions why my team would be off their food.

need advice on how to make the transition from a 2250 lt tank to 9500 lt without fish kills. I have bit the bullet and ordered a 9500 lt poly tank. I have dug a hole to bury it in the ground 400mm. The fish tank will be located 20 metres from the growbeds in an existing greenhouse. I have 12 baths as growbeds and another two to connect in the next couple of days. At the moment im pumping from a 2250 buried ft to the grow beds and draining back to the ft. The plan is to use the existing ft as a sump and pump to the fish tank 20 metres away. I will have a 20000 lt per hr pump pumping from the ft to the g beds (20mts). How do i blend the waters so i can house the fish in the new tank? I thought of just running the pumps a couple of days until both tanks have the same ph etc then draining the existing ft and catching and culling the cohort then moving them to the new ft. does that sound right? Im going to use 50mm rural poly for the flow and return pipes from ft to sump etc. Suggestions and feedback would be greatly appreciated.

Fill the new tank and run some air through it to gas off chlorine etc. A small pump running the water between them for a few days would work. Can you run a pipe from the over flow on one back to the other. Then you just use a small pump to go from tank A to B and have it over flow back from B to A.

I used a bucket to move fish if I don't want to stress them too much. Just have the bucket in the water and when a fish goes in lift the bucket out.

Remember also to salt you new tank to the same level as tank A.

accross the haven't posted for yonks but i have made progress. I have the new tank in place and have run the 50mm lines from ft to beds and sump to ft. I bought a pondmate 27000 lt per hour pump and a float switch, it arrives tommorow. I am all ready to make the transition . The new ft 10000 lts has had water sitting in it for a month. I have caught about 10 silver perch on a le and transfered them to the new 10000 lt tank. They have been in there for 3 days and before that i have had three fish for about a month . Just to eat the mossie larve. I have three air stones but no pump in the 10000 lt tank. The readings are as follows new tank ammo 0 nitrite 0 ph 8.4 and nitrate 0. old tank 2500lt ammo 0 nitrite .25 nitrate 10 ph 7.5. Im concerned about the difference in ph between the two tanks. However i think once the water starts circulating i expect the ph to drop. The water int he 10000 lt tank is green and i suspect recovering from an algal bloom. I think once the water goes to the grow beds the algae will diminish. Just to make sure i am going to put black plastic over the 10000lt tank to exclude the sunlight. Can anyone tell me if i will need air in the sump once i have moved th fish to the new tank? My other concern is the 40 m of black poly exposed to sun in the back yard. It may heat the water so i will have to monitor. I caught a silver the other day 320mm and 600 grams, pretty good effort i think though i suspect a bolter.

moved my fish to their new 10000 lt tank. Last october 1st i put 150 fingerlings into my system. Today whilst draining the old tank and transfering the silvers i counted 147 fish. I was really pleased that is a great survival rate for 1 years growth. I killed one of the fish about two weeks ago and found one floating about 6 months ago, that only leaves one un accounted for. They ranged in size from 350mm to 120mm most would have been between 250 to 275 in length. I drained the sump and caught them in a landing net and then transfered to a bucket and then carried them to the new tank. They all were gathering at the inlet on the surface or swimming amoungst the bubbles from the air stones. The pump i placed in the fish tank arrived today, a pondmate 27000 lt per hr. I have noticed there is an electrical charge going throught the water when the pump is operating. You cant hold your hand there it would be similar to the feeel of holding a spark plug lead. I have an electrician comming tommorow to check it out. The problem is if i return the pump under warranty i wont have a pump and im dependent on it now that i have moved all the fish.
The other problem i have is the sequencing of the two pumps. In the sump i have a 18000 lt per hr pump, the timer turns it on for 15mins on the hr. It then pumps to the ft. The fish tank pump is activated by a float switch the pump is 27000 lt per hr and feeds to the g beds. The shortest range for my float switch is more than the volume of my sump tank. put another way the 1000lt tank drops in level about 150mm. When the sump pump kicks in it takes longer than 15mins to get the water to activate the float switch. One hour later the sump pump starts again and then the ft pump is activated filling the gbs and draining to the sump. So only the second hr of pumping activates the float switch for the ft. Does that make sense. Will it matter? the fish still get oxygenated water in the first pumping. Test results no2 =0 ph 7.4 ammo 0 nitrate 10. Does anyone have any ideas about the pumps and how to sequence them?
cheers Pete

i repaired a section of my concrete sump tank using cement and sand. I also pressure sprayed the inside of the tank to remove agal build up. I drained the dirty water to waste and topped up with tank water. When i checked on the ft approx 4 hrs later i noticed the fish were at the surface and gapeing, moving very slowly and hanging out around the air stones. The next day i came out to find three floating dead on the surface. The next day one on the surface. I got the landing net and scoped the bottom to get 4 more. All the fish were large ones from 375mm to 450 mm in lenght. All had been nibbled on by the red claw. I checked the ph it was 8.4. Im thinking the ph increase may have come from the cement repair effort. Why would only larger fish be affected? One week later no deaths and the ph has dropped to 7.2. In the future what is the best way to lower ph? Overall im pleased with my system as it has been running since 2008 and virtually maintainance free. We have so many fresh veg and flowers. With all this rain we now have 70000 ltrs of water storage. Im going to vacuum the bottom of the tank and top up with tank water. I will post some updated pics this weekend.
pete .

Bluefin....glad to see your doing well, stick some pic's up when you can for comparison