Backyard Aquaponics
A place to discuss aquaponics

I have had a small fish pond with about 500 gal for a few years that now has about 30 to 40 gold fish of varying sizes. I thought I would try a small Aquaponics system to start with using my pond. I have constructed a system with a half barrel using a dyi bell siphon and filled with pea gravel. It is cycling about every 3.5minutes. My pond has an adequate filter for the size and number of fish in it. The water is always very clear and I have no algae problems and never a problem with the fish. I have water lilies and other oxygenating plants in the pond. I also have an air pump and air stones adding oxygen to the pond. There is probably about an inch or two of waste/sludge at the bottom of the pond. I don't remove all of the accumulated sludge from the bottom every year because I like to keep some for my three frogs to winter in as the pond gets about 8 inches of ice in the winter. The aerator keeps a small area of open water in the winter. I have been cycling the grow bed for about 2 weeks now and have added a few plants and would appreciate it if someone can answer some of my questions.

1) Do I have enough fish to support this system?
2) Do I need to pump the water to the bed from the bottom on the pond or can I take it from half way down so I do not interfere with the bottom sludge?
3) Should I shut off the pond filter system and let the aquaponics system filter the pond?
4) Can I expect this system to work?

I have tried to add a picture of my system but it does not seem to be there when I upload it. Don't know what I did wrong.


Thanks

First off, welcome to the forum.

Tough questions to really give you a straight answer but I'll give it a shot.


Depends on how many nutrients are lost to the water lilies and other plants in the pond.


Half way down is OK. I'd shut down the grow bed for the winter and drain it either way.


That sort of depends on the type of filtration and the situation. I'd probably leave the pond filter running and see how the growth is in the grow bed. I don't think the small grow bed would be enough for the pond with that many fish by itself (I haven't calculated it out though).


Basically depends on how many nutrients are left to be utilized by your grow bed plants but I would expect it to work. If it doesn't then it's probably fixable.

Pictures need to be sized correctly - here is a tutorial on adding pictures to a post...

http://www.backyardaquaponics.com/forum/viewtopic.php?f=4&t=21754

Cheers

1) Do I have enough fish to support this system?

adding to Scottys answer,Yes but it will also depend on the quality of food you use,goldfish flakes won’t cut it

2) Do I need to pump the water to the bed from the bottom on the pond or can I take it from half way down so I do not interfere with the bottom sludge?

Again as Scotty posted its ok,i would say its important, you don’t want to disturb that sludge,especially if its been down there for a year.

3) Should I shut off the pond filter system and let the aquaponics system filter the pond?

No the filter will be supplying nitrate and nutrients for your plants,your grow beds will trap the suspended solids the pump supplies so as the bed can continue with the mineralisation process also supplying nutrients to your plants.

4) Can I expect this system to work?

As Scotty posted.

Hi Jonny,

yes its viable to AP a pond, but the size of grow bed will depend on nutrients available.
It will also depend on what you want to grow.

30-40 fish is already quite a lot for 500 Gallons (~2000L).


I actually use AP as a filter for pond system/s to avoid needing a filter - ~1000-1500L.
[ have a few large sealed up planter post with flowers in them ]
Keeps the water clear no problems - the AP becomes the filter and the drop back to pond provides oxygen and nice background noise.
pump sits up on a brick so not on bottom, no problem.


Planning on doing same for my mother as her $200+ pond filter will apparently cost the same to fix....


Don't have winters like that so cannot comment on that aspect.


My experience is that goldfish in a normal setting do not generate the nutrients that plate fish do.
In my goldfish AP with vegie GB's I have to dose with regular Seasol & Powerfeed to get veg up.

With the pond situation I simply grow flowers (marigolds in this case) and hardly ever dose - use water can with foliar fertiliser every now and again if they look like they need it but not very often (mainly for the extra's AP does not provide).

Thank you Scotty, Dasboot and Dlf_perth for your replies and thanks Scotty for welcoming me to the forum. I didn't mention that I have a separate pump running the very small AP system. I have had the pond for a number of years and other than year one, I have never bothered to test the water because I have never had problems with the fish or frogs. I have just now tested the water and as it stands, I have no ammonia, <.3 nitrites and a ph of 8.5. (water temp 20C.) The few plants I have in the gb are lettuce, a couple of cucumber plants, a strawberry plant, and two tomato plants. I have only had the plants in for about 5 days. The lettuce is growing fine. The others are all looking healthy but have had no growth with the weather in the mid 20's C/80F. My main concern was whether I was getting enough nutrients to the gb. The weather has changed significantly today and we are expecting it to be in the mid teens C. (50-60 F.) with lows of near freezing for the next 5 days. I guess I can't expect much growth over this period but when it warms up next week if I don't see any growth, I think I will shut down the filtration system at night and just use the gb as a filter the pond as Dlf_perth suggests, and will test the water quality daily to make sure it stays within the correct parameters for the fish.
Dlf_perth, I am new to this and just thought I would try it out so I don't know about regular Seasol & Powerfeed or if they are available in Canada. Scotty, is this available in NA and if not, could you suggest an alternative? Hopefully, I will have success without using them. Thanks again for your replies. I will update you in a couple of weeks.

I don't think DLF_Perth is actually suggesting that you shut off the pond filter at night without first sizing the filtration provided by the grow beds with the fish load in your pond. It's good that you want to try this out but I'd hate to see you lose your fish. In many ponds oxygen levels drop and ammonia levels spike overnight. I don't know what size your fish currently but the thread below contains some helpful maximum stocking information which is based on final grow out size of the fish -

http://www.backyardaquaponics.com/forum/viewtopic.php?f=12&t=6646

With a pH of 8.5 it will take very little ammonia for it to be in the toxic form. This is the chart I'm looking at - http://ibcofaquaponics.com/information/tables-and-charts/. Considering the pH, I think it's pretty risky to take the other filter offline at night.


Maxicrop is what most of us use in place of Seasol here in the US, either the regular or the one with iron. Because your pH is really high normal iron won't be available for plant growth and you'll need chelated iron or you'll have to spray on maxicrop plus iron since pH isn't as much of an issue when applied this way.

For Maxicrop, foliar feeding 1 Oz per gallon or about 30mls per 3.8 L then spray directly on plants.

For Chelated iron - added directly to the system water. 1 level teaspoon per 1000L every 6 to 8 weeks if pH is above 7.0 and iron deficiency is indicated. Fe-DTPA is light sensitive probably best to apply just before dark (about 96 hours for >90% of Fe-DTPA to be destroyed with exposure to light of the wrong wavelength - usually precipitates out and becomes unavailable to the plants).

Hope this helps

Hi Jonny,

as Scotty says - the GB could replace the filter but only provided the GB matches the filtration requirement. The good thing is that goldfish are not as critical as plate fish - and are pretty tolerant.
But I think you might need more GB filtration - see below.
If you do test be prepared to run the pump & original filter 24/7 if anything starts going amiss.

My mums pond was without a pump or filter for a week in 18-25 degreesC and not too much problem.
So you can do a trial with care perhaps over a weekend first when you can keep a check on things, and then start earlier (eg. thursday, then Wednesday etc) - most problems take about 24-48 hours to develop.


Your main issue will be
(a) your stocking rate - which is quite high (though size of fish is not stated).
(b) having a plant and GB media balance, and enough splash for oxygen.

I actually run my system on a timer with no problem having it turned off for long periods over night,
(cycles hourly 6am-10pm under semi-flood and drain, off 10pm, comes on for an hour 1-2am and back on at 6am) and two of my goldfish tanks have only got pumps running during the day at moment. BUT my stocking rates are not as high and water quality is good (neutral pH).

-----------------------

Your photos explain a lot - one of my setups (an above ground pond basically) is here.
viewtopic.php?f=18&t=23874
this started out being temporary while I re-constructed a section of garden but the fish decided to have babies and so it has stayed and has worked well. It has 4x25L GB to 800L of 'pond' with 8 medium goldfish and few juveniles. I also have ramshorn water snails - which suit a pond situation.

It had an algae issue with no filtration (just pump) initially after 2 weeks in hot weather and full sun, but has been fine ever since after the tubs and flowers were hooked up as filter. So even in full sun - the 4x25L GB has provided enough filtration and nutrient levels are very low/nil. I have vallisneria pond plants in pots.
BUT note:- only 12 goldfish in 800L, so equivalent to 20 fish in your setup (started with 6).

I have now repeated this twice - I use the ponds to provide a self watering flower bed of AP planters in a paved side area outside our bedroom, nice sound of water and have some goldfish swimming around.


My mums setup is similar to yours, about 1500L (300Gals) and I plan to use a couple of large tubs similar size to what you show (plastic 'square' patio tubs). But again flowers rather than vegies.
I would say you would need a couple at least, probably 3-4 for your system to be safe.
** you need the plants as well as the media - that is the main basis for effective nutrient management.


Having said all that tread carefully - it is all feasible but ultimately Scottys advice is correct, and I too would hate to see any problems arise or any goldfish unnecessarily lost.

Seasol and Maxicrop - basically these are supplementary sources as Scotty describes.
(they get described in other threads around here).

Thanks Scotty for your help and the info on the usage of Maxicrop and Chelated iron. As I said, I am new to this this year and hopefully will have some successes. I didn't put much planning into this and I really had no idea coming into this that I would have to deal with all the sizing formulations and chemistry as I wasn't really planning to spend a lot of time on this venture. But we will see what happens this season. The weather has not been too conducive to growing things these past two weeks. 22nd of May and we were down to 0 C. last night(seldom do we get heavy frost this late). Had to cover all of my plants in the regular gardens as well as the GB and the fish aren't eating much because of the cold water temp but it is now warming up and I'll update my progress later.


Darren: Just to let you know, 8 of the goldfish are 6 to 8 inches and the rest vary between 2 and 4 inches. All my plants are still alive but not growing much which could be due to the weather. I think if I don't start getting better growth, I will shut the main filter for a few hours a day and see what happens. I think I read somewhere that it could take four weeks of cycling to establish the the GB so I will give it some time before I change things. You are correct when you say you would hate to see any fish lost unnecessarily. These fish and frogs are my pets, having had some of the larger ones for going on 5 years. It really hurt last year when a the herons came fishing and took a number of my largest and oldest ones.

I looked at the pics of your setup. Very nice.

Thanks

Hi Jonnyrobinson,
my son runs a system here that is an iBC (around 600-700ltes.) with about the same amount of goldfish you have 30-40 various sizes and runs 2 Bathtubs off it as GB's without any problems..

I did see a text saying that Goldfish flakes don't cut it to get the needed nutrients...I have to agree on that but be careful changing over to pellets high in protein.. Goldfish don't have stomach's, and we did loose quite a number of Goldfish changing them over from flakes to pellets and continually do so when we introduce new Goldfish to pellets...for some reason (in this circumstance) they don't seem to handle pellets (1.2mm) all that well...maybe someone on here can further explain if this is or isn't correct... The goldfish seem to get constipated and just blow up and die, cut open a few and found them full of undissolved pellets..

Here's some information I got from Sleepe - he uses a high protein (I think 38%) 3mm commercial pellet soaked for a while to soften. He also feeds duckweed and occasionally gives them frozen baby peas microwaved and then squeezed out of their shells or carrot pulp from a juicer.

"Thing to remember about goldies is they have no real stomach (ie acid producing food breakdown area) and so need extra greens in their diet to make sure they don't get constipation."

What the Goldies don't eat falls to the bottom where he has gilgies (like Yabbies) to eat the leftovers.

it should be fine. The main thing is not to take filter off line too soon - and leave an option for it to be hooked up when/if you do remove it. The usually solution to any problem in an aquatic system is to have lots of oxygenation (splash) and filter (either through GB or filter or both).

as you presumably have a balanced pond already this will not necessarily be the case. By running the filter and GB for a while the bacteria will soon colonise the GB - they are already in your pond (and most likely filter). Your main goal is to try and gradually adapt the system to the GB and not have any sudden change in the existing balance.

opinions vary on the pellets and goldfish - you should definitely try and use a lower protein variety IMO. Others around here do go solely with pellets. In my case I use Skretting 3mm sinking but I interchange with flakes and do not feed pellets every day (good for fish but not so good for AP). I have algae and duckweed. An issue mentioned elsewhere is goldfish surface feeding and taking in air - but others say they use floating ok etc.

Other option is to keep the pond AP fairly low key and look at other options for your vegies. Maybe even wicking beds.
Keep in mind that your pond plants will also use nutrients, so in some respects if you want veg maybe see your pond as a constant watering source rather than a nutrient supply.

Well, I must have done something right. The strawberries didn't do so well but the tomatoes and peppers have done amazingly well. I will probably expand my bed next season.

Images of a two pound tomato from this bed and also the bed as it is today. Thanks to all who helped with their information to get me started.

Hi Jonny,

looks good. Based on fish pond size you could easily have a few buckets like that.
Maybe try some greens next time around.

For what its worth I never had much luck with strawberries either - get a few but nothing worth bragging about.