Backyard Aquaponics
A place to discuss aquaponics

Am probably going to get objections to this but yes. Feed them enough so they finish it in one go, or close to.

Noticed that from your post on the other forum .... a couple of cupfuls....

Measured a cupful at about 150gms... that's a daily feed of 300gms.... for about 900gms of fish weight.....




Short answer ... Yes....

The figures I gave are somewhat dependant on water temperature...

As water temp rises, so does the fishs metabolism correspondingly.... more active, more energy consumption.... more energy (feed protein) required....

Silver Perch will gorge... but the majority of the extra feed is wasted.... their metabolism has to work harder and faster to process the extra, un-needed feed.... stressing their internal organs... and just burning energy to burn the excess energy input...

The majority of the excess feed is just past through, placing a greater load on your water quality parameters and DO levels and bio-filtration requirements...

With minimal nutritional uptake or benefit... most depositied as fat....rather than flesh...

There is also evidence that continual over-feeding and metabolic stress actually leads to nutritional deficiency, and lower nutritional uptake.... less efficient conversion of feed to energy and flesh....

And in the end lower feed conversion ratios... perhaps not a concern to us backyarders, but a major concern to aquaculturalists....

The figures are based upon Stuart Rowlands work... and the published "optimum" feeding strategy for Silver Perch....

This needs to be placed within the framework that these feed rates were designed for "pond based" aquaculture... where a degree of natural feed exists within the pond...

So, it is possible that feed rates may need to be increased somewhat in a RAS/AP system that doesn't have such naturally occurring supplementary feed...

But even if we were to double the suggested quantity... that's still only 90-100gms per day... you're feeding 300gms per day ....

While they may "appear" to be "cleaning up" most of the feed.... my bet, especially overnight... is that most of it is softening into suspension and being pumped into your growbeds..

That last part sounds about right Rupe...
softening and into suspension and being pumped into your growbeds..

Sorry guys, I have now measured the actual amount we are feeding as I was guessing two cups.
The actual measure is under one cup. This works out at just over 1 tablespoon at each feed. We feed four times a day or there abouts.
We are feeding Ridleys Crumbles. They do not dissolve easily as when the food was not being cleaned up overnight it was still there in the morning. We vacuumed the left over food out and cut the feeding back until all food was gone by the morning feed. This is how we reached the current amount we feed per day.

We also have 20 Eel Tailed catfish in the tank making up the total of 182. They are a month ahead of the SP's. They seem to only come out at night from their hiding spots so they would help to clean up the left over food.

So your advice is spot on ROZ.

Alex

Kewl... that's more like it... no sense in vacumning up uneaten feed...

I vacuumed the uneaten food into the sump with the yabbies who soon clean it up.
The idea was to get to the level we now have, a clean floor in the morning, a fresh start to the day.
Thanks for your backup RUPE very much appreciated.
Alex

At last some pics and you would not believe it the camera battery ran out before I got the lot.
The tomatoes are Grosse Lise which do not seem to yeild as well as others in the AP unit.
The veg photo should have been taken before xmas as a major picking took place to supply the hoards over xmas.
Alex

Looks nice and green... and peaceful ... in there Alex ...

awesome size tomatoes

The supervisors are located above the red light in the middle of the VEG pic below.
I had to put an umbrella above them as the nest is only 100mm below the acrylic roof.
Alex

Should have been red light above.
Alex

Hi Folks,

HAPPY NEW YEAR TO ALL

Re my SP's and flashing.

I have salted the water 6 kgs to around 3000lts.
I put 4kgs in on Tuesday and as they were still flashing on Wednesday evening I put another 2kgs in.

I do think that the flashing has eased off but it is hard to say. They scoot around the tank at a very fast pace. Some peel off and cross the tank diving onto the bottom as they go, rolling on their sides through the food left on the bottom and flashing it is hard to say if they are scratching, playing or feeding.
I really do think that like all livestock they play when feeling good.


The Trout are off their feed even though the water has dropped to 22o.
Tuesday the water was 25o room Min 15o max 31o
Wednesday water 24o room min 17o max 30o
Thursday today 22o room min 14o max 29o
In these ranges the water temp is very constant over 24hrs.

Any comments are very welcome.
Alex

This is my new system. These net pots are not new to anyone in hydroponics but at the time I made mine I was not aware of them. Hence my new system.
I had strawberries in the plugs for a couple of weeks but had to put them into the dirt garden in order to salt the FTs. They were going well much better than in the towers.

Some pics

1a) top:- endive in plugs, water is pumped direct from the sump and drains back to the sump using a small flood and drain system all contained inside the pipe.
The water rises almost to the top of the plug.

1b) bottom:- endive in pots of scoria. The water flow is from two baths which flood and drain via this pipe back to the sump. The pots slow the water as it rises around halfway up the pots.

2) endive root system in plug at three weeks. Endive in pots a week older.

Alex

Any more pics Alex? Can't remember the argument (discussion ) we were having that might have helped.
Curious to see the F&D system in the pipes re the plumbing.

Hi Sleepe,
See page 13 re discussion.

Bit difficult to get to the one in use for a pic very simple idea.
Will see if I have enough bits around to make the F&D in the pipe and take a pic.

You can also use this idea in a tower will try to make one and take a pic.

With the strawberries in this system it may block up over the season, it is only 90mm pipe. However I have trimmed the roots of the Endive to see how if would take it. Absolutely no effect on the plant. I would think that strawbs would not mind their roots being trimmed either.
Alex