Backyard Aquaponics
A place to discuss aquaponics

Hi there, I've recently built an aquaponics system by adding a 1000 ltr tank to a home-made hydroponics system made out of PVC pipes. It has a sump with a solar powered pump in it.

It's a very new system - built about a month ago - I put 2 pond fish in the tank and they lived fine for about 4 weeks - but then the water has turned pretty green and cloudy... just after I ordered some silver perch online... So they arrived last week and I've had to put the silver perch fingerlings into the water and it's so green I haven't seen them since, not sure if they're alive or dead. I'm nervous but keep putting food in just in case. (The original two fish are still alive although it's hard to tell if they look healthy because I don't see them very well either)

I don't have any sort of water testing kits...

Since googling I've seen that too much sunlight can make the green algae grow, so I've put some shade around and on top of the tank but it's not 100% blocked off. I built that a week ago and I'm not sure if it's helping yet or not.

But I'm concerned because as I'm reading more I'm thinking that the hydroponics pipes might not have enough grow media in them, because the grow media basically sites inside pots that sit into the pipes.

And the solar pump only works when it's sunny (like, it doesn't even pump when it's overcast and I live near Melbourne right so this time of year that means it's only pumping a few hours per day.)

What should I do?

I'm concerned and feel like I don't know what I'm doing any help or advice pointing me in the right direction would be very appreciated!

Here is a video of the setup BEFORE it went green. Note that I've added a cover on top of the tank now too (blocks 80-90% of light). https://vimeo.com/manage/videos/590249939/bd7caddea2

Hello and welcome. I hope you find the help you need here. You are definitely missing a few things. I believe you need to study the nitrogen cycle as you do not have any biofiltration at all. Also, when using a nutrient film method similar to what you show in your video, you need excellent solids removal so the roots don't get covered with fish poo / gunk. The plant will die or will not grow well.

As for the algae, shade should do the trick, but your fish are at risk of dying now from ammonia and nitrite since you do not have a bio filter. Search for cycling with fish. This will give you a good idea of the nitrogen cycle and cycling your system to establish the nitrogen cycle with some sort of bio filter.

You need to find a model system which you can follow, that should help you build something that can work. Many beginners start with an IBC fish tank and some media grow beds. The grow media provides the bio filtration.

Typically you want a fish tank (FT) with a solids lift overflow (SLO) providing fish water to your grow beds (GB), which then flow to the sump tank (ST). A single pump then moves clean water from the sump back to the fish tank.

If you also want to use the grow tubes you have, then a 2nd pump could take clean water from the sump and supply the grow tubes. You may need a 2nd filter for this to remove the microscopic solids, but maybe not.

Thanks

What if I fill the pipes with a grow media? Take out the pots and put the plants directly into it? So they're like mini grow beds

I would get a water test kit to see where you’re at in the nitrogen cycle. If all parameters are safe, you can wait for the algae to clear up. I would also add a bio filter between the pump and the grow beds as well.

I don't recommend this. The water and fish waste will enter at one end and travel through the tube(s). The inlet end will clog quickly. And the tubes will definitely be clogged with roots if they have media in them. Also you will never have enough wet media to fish ratio to be an effective bio filter.

Especially when you are starting out, stick to something that is a common design, "tried and true" so to speak if that is possible with aquaponics. Start small to gain knowledge and experience and minimize the cost and losses.

And get a water test kit or just pack it up and quit. If you're not willing or able to manage the water quality you are headed for dead fish and dozens of other problems, questions without answers, etc.

Tried and true systems account for:

Water testing
Fish tank / fish to wet media ratio - adequate bio-filtration
Sump tank to allow for evaporation and water level fluctuation, and to help accommodate all the water if power fails
Solids management - deliver to grow beds or separate?
Problem plans -
How are solids removed from the fish tank? Where will they go?
What happens when roots clog the GB drain(s)?
what happens if the water does not return from the grow beds?
What happens when the power goes out?
Etc.