new system in port kennedy

[wa shane]

castaway in answer to your question i have silver perch 80mm to 100mm.i have also included some photos of my system.I have used pea gravel instead of expanded clay, yes i know tight mongrel.but still learning.I have been looking at your growth rates,blows me away

[Castaway]

I don't think it makes the slightest bit of difference what gravel you use. You have a neat looking system. In relation to your earlier posts about spindly growth, I'm wondering if your system is getting enough sunlight as 80 Silver Perch must be pumping out a fair amount of Nitrates but your readings were pretty low and the plant growth looks fairly lack-lustre. Are the fish being well fed and eating a lot? I'd check to see that water is getting to your plant roots and there's no odd blockages as your other grow bed with a silver beets looks great.

[wa shane]

As to been blocked the answer is no,feeding is not great, i feed them a tablespoon to each tank at somewhere between 2 and 6 pm.They don't seem to eat all the food and there growth is not great.the food i got from a fish farmer who in turn got it from tassie.he uses it with no problems that i know of.

[Castaway]

Are the fish sprightly when you put your hand into the tank and zip around in a lively manner? Or sluggish and just like to mope around not moving much? Maybe not enough dissolved oxygen or water temperature too cold? Check the water temperature and crank up the oxygen going into the tank. You are using an aerator to air stones as well as the main water pump splashing water back into the Fish Tank 24/7 or on timer?

DPI Silver Perch recommendations are: Temperature tolerance ranges from 2°C to 35°C. Optimum growth rates occur between 20°C to 30°C and growth is negligible below 12°C.

I know the Jade Perch I got are still eating strongly. Water temp is 23 degrees. They are very sprightly and zip around with plenty of energy occasionally bashing into the sides of the tank with a thump which all points to healthy fish. I also feed them picked greens from the growbeds above them which they love to eat. Try varying your fish diet as well.

[Murray]

My water temps are down to 14.7 this morning. Fish all off their food. It is amazing how much the water temp affects their behavior.
I really don't want to electrically heat the tanks this winter. Power costs here in SEQ have gone up close to 30% since the Gov did us all a favor and privatised the system.

[Castaway]

My water temps are down to 14.7 this morning.

14.7?!! Gosh Murray! Thats Cold for SE QLD. I'm right on the coast so the temps are more stable and warmer. Still - I would have guessed you'd only be down to around 18 - 20 degrees. You probably get a frost at your place in Winter? I've been rolling a rubber mat over the fish tank hatch at night as we've had a few cool nights - but forgot last night but I dont think it makes any difference. Sun on the clay beads during the day warms up the system a bit. Only need a strong cold offshore wind to drop the temperature quickly.
I wonder what the temps are in Perth?

[wa shane]

I've just checked my water temp,and it's 21c,at 11.33pm.The average temp max is 27.7. The min is 13.7 in this month of April 09.Something i forgot to mentioned is the fish food i brought was 5mm, i crushed it down to fine flakes,is this to small.Have also been thinking since my nitrate level is down would it hurt if i dropped say, one teaspoon a day of urea into the system, to bring the nitrogin levels up.And If so would this also sustain plant growth through winter

[GaryD]

Hi,

I wouldn't use urea in a system that already has fish in it. Try Seasol instead.

Gary

[wa shane]

Castaway when you say vary the diet what do you suggest

[Castaway]

Silver perch are omnivores consuming zooplankton, small crustaceans, aquatic insects, molluscs, algae and plant material.

There's probably nothing wrong with the pellets you've been feeding them but try offering them a variety of different feed and watch and see if they show any interest. A lettuce leaf for example. Strong water temperature swings of a few degrees can also play a part in putting them off their food. Add a screw cap lid full of Seasol concentrate directly into the water tank every morning to keep the plants growing, adding vital trace elements that they need.

[wa shane]

So should i be adding trace elements into my system on a regular basis, and if so what and how much.

[Castaway]

Hi Shane - Read some of the info on this link (http://www.aquaponicshq.com/forums/showthread.php?t=901) about plant nutrients to add to your system. There's actually quite a lot of info on this forum if you use the search button. Its been quite extensively discussed already - everything from minerals, chelated iron, calcium carbonate to eco rose and more. The info you need is all here but you gotta hunt for it a bit.

[Outbackozzie]

Shane - did you get the silvers from gidgegannup fish farm, or golden ponds?

[wa shane]

Got the silver perch from gidegannup fish farm,i hope this wasn't a bad move.

[Outbackozzie]

He sold them too small. Full stop, no return. I brought 500 back to Kal, and the only ones that have grown are the ones in my aquarium, heated to 26 deg c. All the rest have gone to various homes throughout the goldfields, and have not grown at all - hence no plant growth.

Around 50% of these fish survived.


WA Shane - After reading through some more info i should tell you more about the start of my system.When i added the fish to the system on the 25.2.09 after it had been fishless cycling for 13 days,the ammonia was about 5.0,nitrite 4.0,ph7.6.Being a novice i acted slowly on murray's dvd advice. I did a 1/5 water change . This helped but i also got some bacteria water from backyard AP which in 3 days brought it down to, ammonia .50 and 1.0,nitrite .50, nitrate 10.Quite amazing what that bacteria can do.Things are better in regards to water readings, ammonia 0 and 0.25,nitrite 0,nitrate 0 to 5.0,ph 7.4.So with this info have i done damage to the fish and caused them not to feed properly and caused the plant growth to be slow.I have added chelated iron to the system 3 days ago plus the recommend seasol, cap full a day. I'm tossing up whether to add some eco rose, but i'm usure of the amount.


The fish will definately be damaged, at that time of the year you water would have been in the mid to high 20's, well into toxic range for the ammonia. I'm surprised you didnt loose all of them really.

[wa shane]

Ok thanks for that oz where do you reckon i should go now to get some better fish

[Outbackozzie]

Trout. Lots of Trout :D

If you want some I can put you onto a fella in Bunbury, who delivers to Perth.

[wa shane]

pretty keen on silver perch if i can get them

[Outbackozzie]

They will not grow over winter. Any that survive (a lot wont at the size that they are currently available at) will not grow even 1 cm more in length.

Overwintered SP fingerlings are often available in October, in limited numbers. These are around 10cm long. Yours will not get to 5cm in the same time.

The farms get them to a good size because they are in large ponds, that are a lot warmer than your AP system will be. These 10cm fish are usually $2.50, compared to what we all paid for the tiny silvers ($1.10?) they represent great value at that size.

[wa shane]

Ok will try the trout how many do you reckon

[Outbackozzie]

20 - 30 in each IBC.

[wa shane]

could i get the details of the bloke in bunbury please oz

[wa shane]

Thanks for the info oz much appreciated.Just another question you seem to have a pretty good grasp of AP would you mind if i ask long have been doing this for.

[Outbackozzie]

Started the first system in Oct 07. At that time I read every single post in this forum and BYAP's forum, it's got too busy now and I cant keep up though :(

[wa shane]

OBO i have been reading a bit of info about salt level in FT.Should i have added salt to my AP first up and if so, am i to believe it should be at 2ppm