Backyard Aquaponics
A place to discuss aquaponics

Hello people,

Im new to aquaponics, i have recently set up a system out of 2 x 150 litre tubs, flood system with auto syphon. approx 2 months ago.
I planted lettuces in to begin with. all seemed to be going fine other than the occaisonal caterpilla, then all of a sudden, my plants stopped growing, they still look ok, but not growing.
I planted 4 capsicum seeds in soil in pots, dug up one seedling and put it in the grow bed whilst leaving the others in pots, the ones in the pots are about 3 times the size of the one in the grow bed, the aquaponics should be much more advanced, its like they are being stunted. i have also added basil, thyme, not growing either. I would say the leaves on some are lighter than they should be.
i was adding a small amount of seasol each day, i dont do that very often anymore because there was algae growing in the fish tub on parts where the sun hits, is my assumption of algae a good indicator the the system isnt lacking in nutrients?
i have tested the system for ammonia, ph levels, nitrites and nitrates. they all seem to be ok.
any hints on other things to try? i heard low iron levels can impair the plants ability to take in nutrients? could this be the problem?

any help with my problem will be greatly appreciated.

im new to this forum thing too, sorry if i have posted this in the wrong spot..

Hi Grombo and welcome to the forum. A couple of things that instantly stand out to me are
If you have algae growing it will be taking nutrients that would otherwise be taken up by the plants. Block the sunlight to the fish tank, this will help. Also nutrients available will also be dependant on fish feeding and number of fish in the tank.
Another critical factor if winter is setting in on Melbourne you should be growing winter veges such as silverbeet, cabbage, leek not capsicum. To get the most out of a system it is advisable to work with the seasons.
As I am not sure whether your system is in a greenhouse or exposed to weather conditions, all these factors will have an impact. Perhaps you could post some photos for us We love photos here. Feel free to ask questions.

Thanks for the friendly welcome.
I have since blocked out the sun to the tank, hopefully this will help. I have about 13 goldfish, they arent very big. i will keep those plants in mind, i will buy a punnet of a winter plant and see how they go. If my photo comes up with this post you will see it is semi exposed. I have made do with the materials I have lying around as I am renting so cant build a permanent structure.
also I have noticed the water is getting very cold as the weather is setting into winter, should I get a heater?
I have also down graded my pump as the orange one in the photo was 100watt and pumped way too much water, i know have a 15watt pump that is much more economical.

looks like you have the basics right, seasol does not provide everything that plants require. It has no Nitrogen, which is provided by the fish eating food. No fish eating (or small fish) = no nitrogen = no growth.

You don't need a heater... goldfishes should do fine in winter except that they do not eat as much and hence do not provide as much waste (ie. less ammonia and hence less nitrates)...

What is your nitrates reading anyways??

Also just check on the amount of sunlight the plants are getting daily... the dark charcoal skylight may block too much sunlight out during winter... in winter, those of us with shadecloth will remove the shadecloth to allow direct sunlight for the plants...

Also, goldfish food might not be as nutritious for the plants. Lots of feeds meant for aquarium try to keep the nutrients as low as possible while still keeping the fish alive since the only way of controlling the nutrient levels in a non planted aquarium is through water changes. In aquaponics, we actually want a good amount of nutrients so different feeds are more appropriate.

Then again, the algae sucking up nutrients and the change in seasons is probably where your issues lie along with it being a fairly young system.

Good Luck with the winter plants and hopefully you have enough sun for them to thrive.

Ok so I have taken the laser light off as it was tinted, need to get more sun to my grow bed.
I have put laser light over the water to stop the algae growing, in the fish tank area.
I tested the water this arvo after work
ph is 6.5 - 7.0
Nitrites 0.0
Nitrates 0.0
Ammonia 0.0
I last tested the water 3 weeks ago, I am not sure what happened as it was on its way, had good levels of nitrates, nitrites and low levels of ammonia also neutral ph level. it was on its way to being a healthy system. I did top it up with tap water, does this effect the bacteria living in the water?

I have also purchased some fish feed due for delivery later in the week, I hope this helps.
Also does anyone know where to purchase small qtys of silver perch? 20 or so, I can find sites but min qty starts at 50, thats way to many for my system.

Cheers.

I believe your system is cycled, you just need more ammonia to get more nitrates for plant growth... the algae may have been competing with the plants... you can still place a small sheet of skylight over the fish tank to prevent further issues with algae blooms...

Topping up the tank with small quantities of tap water should be fine...

If I am not wrong your tank is about 160L to 200L with equivalent volume of growbed... 20 silver perches is too many for your system... Read this... http://www.backyardaquaponics.com/forum/viewtopic.php?f=12&t=6646

If you can find an alternate home for the goldfishes, trout would provide more growth and waste during the winter months..

thanks for the advise, one of the problems with a small FT is it is not economical to purchase fish, they are pretty expensive from the pet shop. i might have to try and catch a few.

From your location, it appears that you are in the melbourne area... Post in the appropriate section of the forum to see if someone is willing to sell you a few fishes... or get a few extra when they buy their fishes... and you can pick them up from them... you just need an esky with some air for a short trip...

Fish caught in the wild are very hard to get on to feed so far in three years i havent heard of any body growing some out to plate size

I purchased an batert backup air pump off eBay, it should do the job. I have a friend that caught a yella and put it in a tank, I think he fed it yabbies, worms and fish. dunno if he got it onto artificial feed. I've noticed there are a few AP's in my area, I'll post a request.

Just adding to that feeding wild fish frozen prawns at $1.00 a can isent economical

We used to have a redfin in the pond for years, it got pretty big until dad used an old washing machine hose for a pump, it died, theyre must have been chemicals leeching out of the plastic? The only place i know to catch alot of reddies is sugarloaf, but they are unedible due to the mercury levels in them.