Backyard Aquaponics
A place to discuss aquaponics

Welcome to your first disaster, JAF. Always a bummer, but having a lot of goldies breeding is fun (and is something I've never managed).

Anyway, where to begin?
>I think pond turnover and filter size should be appropriate for the number of fish rather than simply the volume of pond, but more flow/filtration/aeration is always good.
>I agree that black gravel WILL burn your plants. Shade cloth or even simply laying newspaper on top of the gravel should help.
>check out natural swimming pools. The filtration area they call for is 2x the surface area of the pool itself and loaded with plants. At the same time, other folks in this forum have raised really nice fish and enjoyed swimming in their pools.
>nutrients are going to be a problem. If they are high enough for your plants in the growbed they may produce intense algal blooms, while keeping levels low will probably lead to poor plant growth in the growbed/filter.
>Are you planning to swim, have dogs in there? If not (or even if so), some surface shading with water lillies will suck nutrients, shade out algae, and reduce evaporation.
>As noted, extra pumping for fountains or a waterfall will help with O2, black muck, and other water quality issues. You could have it on a timer when things are not so critical so it comes on in the arvo/early evening when one might enjoy the sound and a beer (and it will help oxygenate and cool the overheated water).

Good luck!

Thank you for the constructive comments.

My water test results were pH 7.5 and ammonia and nitrite were both zero. I guess that is consistent with too few fish. Unsure if the pH is too high - it was at the highest end of the scale on the colour card.

Despite the low Nitrite and Ammonia, I am having a bit of a problem with blanket weed/ algal growth. I have a smaller pond with a similar set up and the blanket weed is nearly over 1/2 of the pond surface. The pond in this discussion is just starting to show significant algal growth, even before the topsoil incident. Seems a contradiction that algae grows while other plants struggle.

Seems obvious now, but I should have realized the black scoria would overheat in the sun - I will have to replace perhaps the top 1/2 of the trough with a lighter stone - I know there's been some discussion re: growth media in other threads and will check this out. Also will adjust the flood time to reduce height water reaches.

Obviously I'll have to invest in more filtration and aeration to achieve the levels recommended if I'm going to get anywhere near the levels of plant produce and fish survival that others achieve.

Whilst I don't intend to swim or have dogs in the pond, it would be nice to get the water quality sufficiently balanced that it is clear of algae, but the ornamental and edible plants thrive (and the fish live!).

Can anyone point me in the direction of a thread on filtration with perhaps a guide to ratio of amount of filtration: fish mass. I've realized I need to do more homework - but that can be difficult when life's events take hold!

My primary aim is to have a working ornamental pond - not necessarily a swimming pond (but that would be a nice bonus). Secondly, If I could grow some vegetables in a grow bed that would free me from having to use conventional nonproductive cannister filters, that would be even better. And thirdly, if I could grow some edible fish in the pond that would coexist with the goldies, that would achieve, for me, a state of aquaponic nirvana!

I wonder if I'm aiming too high?

Hi JAF, I am no expert but I am sure you will get plenty of help from this site. I you do put plants into the edge of yur pond keep them in their pot, and sink the pot so top is just under water level. Stand it on a brick oif you have to. I had the same problem with algea and it wasnt until I provided some shade albeit unique it did the job. Water went brown but now after 3-4 weeks is clearing up and the water plants have never looked better.
Try this is your Google.........fish ponds aeration filtration.


I know, piccies

Your algae growth is simply because of a lack of filtration. The algae is using the nutrients before the plants get it. Your plants are getting wet feet, and being burnt, and you dont have enough oxygen to counteract the algae + fish's usage. You dont need to replace the top layer of gravel, just shade it until the plants are able to take over. Lower the flood level of the gravel bed, it must not be wet at the sirface at all.

Goldfish do fine with very very little oxygen, they will gasp at the surface very effectively. Silvers dont.

The filtration ratio is related to fish mass, however the first consideration (especially with a sunlit pond), is water amount. You really need at least 1/2 the volume of your water as growbeds, ie 7500 litres of gravel. Thats before adding fish. Ideally you would have 20,000 - 30,000 litres gravel, this would guarantee clean water and very healthy fish.

You can get away with less, but your water quality will suffer, and the system will be prone to crash/overload.

Thanks CS and OBO. Nice pics. What were the plants in the pots - I recognize the tomatoes and rhubarb.

Your posts and pics make me realize how under filtered my system is.

20-30,000 litres of gravel is enormous - at 300mm depth (I gather that is the recommended depth for a grow bed?), that would mean I need 100 sq m surface area of grow bed. Of course that assumes the pond is fully stocked (how much fish is that based on?).

Looks like I should have planned a smaller pond. Or at least I should keep the stocking level down. The alternative I guess is I'll need a large pool type filter to do some of the filtration, if I add more fish, and leave the rest to the grow beds (which I'll hope to eventually add to).

Hmmm.....plenty to think about.

Here are some of the often repeated rules of thumb about filtration and other things.
http://backyardaquaponics.com/forum/viewtopic.php?f=12&t=6646

I highly recommend reading the basic info and useful info sections of the forum as completely as you can. Those can save you much time asking about the basics and chemistry and algae etc.

I also usually recommend picking a few big member systems threads to read through. Perhaps some of the swimming pool or pond threads would be good to help you sort out how much filtration you really need. Problem seems to be that getting enough filtration on a large amount of water without going broke on pumping and gravel can be a real challenge to find the right balance.

I think an ornamental/aquaponics system can be done, however, I don't think too many of us here have found the right balance with such a system yet (large amount of water with ornamental pond plants plus edible fish and veggie grow beds for filtration.) Trick is figuring out how to get the filtration and veggies going when the pond plants tend to go after the ammonia first. And then there is the issue of algae in the fish tank/pond that is not easy to shade.

Good Luck

Hi JAF, They are:....... Seagrape (big leaf) Dwarf Mango, Rainbow Silverbeet, Dwarf Tahitian Lime, Dwarf Mandarin, Jaboticaba. They are all growing in Searles potting mix. Watered from the fountain and drains back, when I remember to turn it off. It has 3 goldfish and 2 yabbies, only see them now and then.

Just an update.

Been OS for a month. On my return, my initial fear was - no sign of life in the pond - but there are about 30-40 goldfish (they've grown), their 10 or so babies (now quite large) and surprisingly, maybe 20-30 s.p. left (and they've doubled in size).

Before I left, I put the bore water on trickle for 10 hours a day to overfill the pond hopefully washing away the "bad stuff" and installed a large cannister filter (supposed to handle 12,500l pond) connected to a 12,500l/h pump teed off to a fountainhead for aeration.

I borrowed a septic tank aerator (monster of a contraption) from a friend who makes them, but found this too difficult to install in the day or two I had after Xmas before heading off OS.

So presently, I am tinkering with my grow bed (you might recall - a converted 3m long x 0.5m wide x 0.3m deep cattle trough) to get better flow and shade to hopefully get some production here.

Seems I've been very lucky this time. Some important lessons learned. Thanks to all who took an interest and offered advice.

Will be checking out other parts of the forum and probably posting another question or two!