Backyard Aquaponics
A place to discuss aquaponics

Trout are a whole different ball game i find 50 trout in 1000 litres i am pumping 4 min every 1/2 hr and with plenty of air they are ok
Where the other 50 in 1000 litres pumping 15 min every 2 hrs also with plenty of air there water suffers a bit from suspended solids and needs 2 cycles a day of 1 hr pumping

I have been away for the weekend and the fish have not been fed. The water looks heaps better. I can see the bottom of the tank.....first time in a long time. I am thinking of increasing the pump time so it gets filtered more. Twice a day I will increase the pump time to 30 minutes, drain for 30 minutues. I will have to have a play around.

I am only feeding a cup full of food a day. Am I feeding too much? I am not sure how much they weigh, we ate a few a couple of weeks ago and they were around 190 and 160grams each.

I managed to pick up a box full of yabbies on the weekend. There are some really big ones, I have not seen them that big before. I am thinking of putting some into the fish tank to clean up the bottom. I will put some pvc hides in the bottom and see what happens. Has anyone had any luck with keeping trout with yabbies? I know that trout like to eat yabbies....hopefully they will be big enough to find spots to hide.

We caught five fish today with an average weight of 213grams. The water is a lot clearer. You can see the bottom clearly when the light is right. My test results are still not perfect
ph 6.4
am - .25
nitrite - trace
nitrate - 40

I want to significantly increase my feeding level. I worked out that with my average weight of fish I should be feeding them 1 3/4 cups of food a day. I am only currently feeding them 1 cup. How do I increase my feed levels without the water going 'bad'?

Why are my levels increased? I can't seem to get them to zero. The system has been running for over 5 months now, I would have thought it would have cycled and be able to handle the current fish load.

Any comments would be appreciated;

How many fish you got in there now?

I haven't read back through your whole thread here so I could be missing something but I think you said you had 3, 500 liter grow beds supporting this system. You might be nearing the limits of that system.
with a fish tank of over 2000 liters and only 1500 liters of grow bed it is hard to make sure all the water gets through the grow beds enough. I would guess adding one more grow bed would greatly improve things but you still won't reach max stocking for that size fish tank with only a 1:1 ratio. See the 1500 liters of grow bed should be able to support about 45 kg of fish but that is also assuming you are circulating the volume of your fish tank through them each hour. If you only run the pump enough to flood those grow bed once an hour, then you might only be circulating about 600 liters each hour which could explain why the over 2000 liter fish tank is having water quality issues.

Seeing ammonia and nitrites show up again is a pretty good sign that you are running near the limits of your filtration and/or circulation. You might be able to help things along by adding filter boxes or something like that the way Rupe does.

Yep, was more first thought as well... pudhing the limit of filtration... another growbed might make all the difference... and you've got nitrates to spare...

Not only would you gain from the extra bio-filtration and solids capture... but you'd also increase your volume turnover... you'd probably find you could feed to the level you want...

But might still be pushing things as the fish near harvest, and you've had to feed even more...

Do you have extra air already running into the tanks? I would guess that you probably do though with trout.

I find as my fish grow 100 trout 4 to 500 grams and now feeding 5 to 6 handfulls a day i have had to increase my pump times [once a day run pumps 2 hrs straight]

Thanks for everyones comments. At the moment I have 65 fish which is around 13 kg of fish. I have taken out most of my vegetables and a lot of seeds have just started to germinate. currently I have three silverbeat plants, around 20 broad bean plants, 8 cabbages (1/2 size), and half a grow bed of brocolli. My nitrates level has increased dramatically as I took out lots of mature plants and replaced them with seeds. I have constant air running to the tank.

If I add another grow bed do you think I will have enough water to keep the tank filled? I have been thinking of adding another grow bed for a while but am worried about the water level. when all three grow beds are full the fish tank is just over half full. I was thinking of adding a grow bed and another sump, but then I have to run another pump to return the water to the fish tank.....more running costs. Or I could just add drainage pipes back to the existing sump. What does everyone think?

I will increase pumping time for a solid hour and see what happens. Food and Fish, when is the best time to run it constantly....day or night?

Should I increase my pumping now and start increasing the feed.....when people say increase it gradually...what does that mean? How much should you increase the feeding by per day? I am thinking of adding a 1/4 of a cup for a few days then another 1/4 of a cup until I have added the extra 3/4.

Is this good?

Lets start with are you trying to keep it hot or cool for hot pump in the day time for cool pump at night
It realy wont make much difference to the temp
Thats over summer over winter reverse the pumping times
For feeding increase 1/4 cup for a week then 1/2 for the next week ect

If you have an existing sump, then yea just run the plumbing to it.

Thanks everyone. I will give the extra pumping a go and see what happens.

I have increased the pumping to two - one hour blocks a day. The rest of the time I am pumping 15min, draining 45min. Water tests today
ammonia - .25
nitrite - .25
nitrate - 40
Hopefully we will see the results coming down in the next few days. I have kept feeding at one cup a day.

The extra pumping has worked extremely well. The water is now crystal clear. Water tests yesterday showed just a trace of ammonia and nitrite. Yesterday I saw a big trout swimming slowly near the top of the water. It looked a bit sick. This morning we saw the same fish looking sick. We harvested it. It has been our biggest fish by far - 293 grams. Its gills looked very red. I am thinking that it has been effected by the nitrite reading. I have put 3 kg of salt into the sump tank.

Last week was really sunny and hot. It has made such a difference to the water level in the fish tank. The system has been running since April with no top ups other than when it has rained. The tank levels had dropped to about 1/2 when the grow beds are full of water. I have started a slow trickle from scheme water to restore the levels. I must investigate an automatic filler.

Today we removed the floating rafts. We found they just were not very effective. When the trout feed they tended to splash water onto the top of the raft. This made the bottom leaves of the lettuce all brown and yuck. It also stopped us seeing the trout. Now that it is removed we can see the trout clearly again. We are going to have to cover the fish tank with something else to stop the light getting in.

The fish are getting bigger - around 200grams. We are going to start harvesting them as we go in preparation for summer.

When are people from Perth planning on getting barramundi?

Well we have had another death. Around 27cm, 260grams. I have done water tests and the ammonia and nitrite level are .25. I am feeding them 3/4 cup of food in the morning and 1/2 cup in the afternoon. The gills of the fish looked okay. I am not sure why I am starting to get deaths. We stirred up the water when we removed the raft....I wonder if that has contributed to the deaths?

If you see a fish looking sick do people kill them and eat them?

The water temperature got up to 20 degrees today. This saturday 32degrees expected. I am a bit worried how hot the tank will get. I am going to get some ice organised tomorrow. Will see what happens over the weekend.

I salt, and heavely, i don't weigh the salt in a sick fish's need



the fish might of got some gunk in there gills and choked