Backyard Aquaponics
A place to discuss aquaponics

Yes I did it a week ago with a water change and things are great now.
I desire this too. My only technology is a pump and homemade electronic timer and will stay so.
I actually started out with a 10L system, hand-watering gravel filled half litre plastic bags!(recirculative, aquarium tubes from the bags sent drain water back to fishtank um... fish-bucket.) Mint grew well in that system (not even a pump!).
Watering morning and evening and (every 4 hrs on holidays) by siphon and hand was tedious.
So I bought a pump.

Now do you think I am going to go for (unneccessary) high tech?

Yeah, my comment wasn't directed to you gokul. I don't know how else people would expect you to calculate surface area except using spheres as an approximation.

The limiting factor is probably the amount of oxygen available versus the area.
With an unlimited supply, as in the case of biowheels, the efficiency of the bacteria is reported to increase even though the population size and surface area doesn`t change

With a drained gravel bed, the bacteria essentially have access to the huge 20% oxygen of the atmosphere through the thin water film. In F&D oxygen is not at all a problem.

Seems I've worded things badly perhaps.... my contention is that in fact (other than perhaps a system that only floods once per hour... ie say a timer system 15mins on/45mins off)....

This isn't the case.... and most people aim to turn over their entire tank volume at least once per hour.... that's probably in systems with a 1:1 ratio....

Even in timer based systems I think it would be fair to say that in those cases the drain is (relatively) slow..... i.e there could still be 50% of the growbed water volume remaining in the growbed for > 20mins....

And after 45mins a new flood starts..... the actual time even in these systems that there is only a thin film of water around the entire volume of growbed media is probably minimal....



I don't think we need to get hung up on a "snap shot" scenario.... the process is continuous....

Does it matter if ALL the water film is TOTALLY processed in a given time, or is it more important that we have enought filtration capacity to acheive the end result...

The hypothesis doesn't hold up if you were to consider a continous flow and continuous drain system would it?

If we consider a flood and drain system (regardless of the type of media) as a partially continuous flow and continuous drain system we might weight the proposition slightly...



Pretty much what I'm suggesting above...



Yes indeed, certainly if you don't have a large capacity of growbed/filtration media... in Gokul's case 1:4... and I think Steve posted his is 1:5....

Otherwise as you've both suggested the amount of bio-film.... filtration is insufficient to process the volume of the fish tank......

In which case you need to reduce your output... fish respiration/ammonia and /or uneaten feed by either stock fish to the levels of your filtration capacity... as many keep trying to highlight to people....or reducing your feed.

Or increase your turnover... processing...

As we want fast growing fat healthy fish to eat it just makes plain commonsense to match your stocking levels to your filtration capacity... both volume and volume turnover...




Which is exactly what DD is saying as well....

It's not that Steve and I are hung up on "gravel".... all the arguements put forward apply equally (allowing for relative differences in media type/volume) to whatever media is used in your growbeds.....

Some like perlite/vermiculite and coco-peat retain much greater amounts of water (hence by your arguement more bio-film) than gravel, hydroton etc...

There's a place for external/add-on bio-filters that have been used in aquaculture and aquaria... if you want to isolate/disinfect your system or parts of it .....

Or if you have insufficient growbed filtration capacity or plants to process the nitrates...

AP is such a beautiful "holistic" closed loop system that while you can (and some certainly do) open the "loop"... the point being made is that it's not really necessary....

If you learn and understand the principles when first setting up a system, it will essentially acheive a balance that requires minimal adjustment and intervention..... surely the way to go for anyone new to the concept of AP....

If you want to experiment with a second/expanded system fine.... but do so understanding the basics first or trouble shooting your experiment becomes a nightmare....

It's possible to use additonal bio-filters, solids removers, skimmers etc.... but the question everyone that does so needs to ask is why?.... what are you trying to acheive... and do you understand the basic concepts/chemistries etc sufficiently to acheive what you're setting out to do and to understand why it's ultimately successful or not...



Had no problem with the concept of using the sphere as a means of approximation DD....

Just questioned the initial premise... which was based on a slice of time in a system that flooded 15on/45 off....since then Gokul has explained his system and ratios, and I think it's even more important that we have expanded on the question....

The premise was too simplistic IMHO and constrained by singular variables in a small slice of time....

Not a situation that applies to most systems IMHO.... and one which I was trying to highlight presented shortcomings if we were to get hung up on the premise...

Gokul, himself after explaining his current system has perhaps begun to understand why some of his problems have occurred and hopefully gained some ideas of how he might correct them...

Sorry, but sometimes I think you (generically) can "over-analyse" a simple concept.... the questions is why do you/we do so....

For greater understanding.... kewl.... for innovation ... doubly kewl....

But sometimes it's just better to adopt a position of "if it works, leave it alone"....

And for someone new... KISS.... then experiment...

my point is that the last three pages have been based on a premise that there was insufficient biofiltration because of a perceived ammonia content with NO measurements.

and the quotes are getting tiresome to read. lets just get on with it.

yep, sounds like some one was getting a little impatient with their new system, using only their nose, fish behavior and the look of the plants as their testing equipment.
A challenge (or painful) to smell the spikes so to say.

Sounds like the system only just got to the cycled stage around the time of the start of this thread.

Did you mention the stocking rate of this system? As mentioned before, that whole 2:1 ratio is really only if you are stocking the tank to capacity. Most people actually have much less grow bed than that and they just go with lower stocking to avoid problems or they have to feed less or do water changes to compensate.

One of my favorite things about the biofilm layer getting going, when you do something to cloud the water, it clears much faster once the biofilm is in place. When I hooked up the first two grow beds on my big system, it took weeks for the water to clear but now I can fill up a new grow bed and the water usually clears in a day now!

Enjoy your system now that it is cycled.

Thanks.
I'm using 3 2.5 inch goldfish in 50 L of water and around 15 l of growbed.
(It is actually made of two tubs - 20l and 30l connected together. The 20l tank actually has two guppies and 6 0.5 inch tiger barbs which I think are hardly messy compared to the goldfish in the separate tub. I added goldfish because I needed more poop, for more plants.)

Although the system itself has been upgraded and modified several times, the bacteria have been around for 4 months (I have included initial cycling time though - maybe a month). (These 4 months are my entire fish keeping experience. I have spent weeks reading at wetwebmedia and then this forum now for more weeks (months?) than that.)

I fear this would go off topic and become a members system thread but I can't resist putting this extra info:
Initially after a month and a half (when I first learnt about AP) I made my fish system into an AP system and mint did grow well, with only two 1.5 inch tiger barbs!
But it had hydrilla in it that I got from a local pond.
These weeds grew big (I was happy then). Then plant growth stalled (green seedlings remained fresh and green - seedlings - for over a month.)
Not knowing the cause I bought the goldfish (=messy poop mmmm...) and waited for bacteria to catch up.
Still no growth.
Finally moved the system from my window sill to the west facing outdoors.
Still stalled plants (still green!)
I also got an algae bloom which is now gone as I covered the tanks, with a 50% water change.
Only a week ago after removing the weeds, the plants are picking up!

I want to point to this interesting link about how water plants can help in the aquarium (not an AP system, that is, only terrestrial plants can help here!).
http://www.aquabotanic.com/plants_and_biological_filtration.htm
It says aquatic plants prefer to absorb ammonia /nitrites than nitrates.
This is bad for AP because this competes with bacteria, sometimes you may not even need them!
So no nitrates, these aquatic plants rob the ammonia before anything can happen.
You also get a false belief that there's plenty of bacteria doing the cleaning.

This is great for aquaria but a disaster for AP.

(I know most of you know this, almost everybody here knows duckweed absorbs ammonia).

This was one of the biggest reasons for the plant stalling in my system. Also the spikes and fish deaths, because when I increased the fishload thinking the terrestrial plants needed nutes, there was a spike, because there were little bacteria and the aquatic plants couldn't suddenly grow themselves to match the extra load.
Really foolish I felt, I needed one month to pull out the aquatic weeds!

gokul,
Keep up the good work and remember patients.

Remember that even though you started up some gravel 4 months ago, the bacteria population and cycle level is going to be closely related to the waste level. As you mentioned, some of those fish don't seem to have been producing much waste so your initial population of bacteria was probably pretty low. Then you added some poopier fish, the cycling process had to work up to the new load (hence perhaps some of your spikes/smell issues.)

If you can get a test kit, it will allow you to move forward more quickly/confidently but if that is out of the question, I guess you should just carry on as best you can. You may risk loosing some fish if you push too hard to fatten them up and produce nutrients for the plants.

If you are more interested in plants than fish, there are other alternatives, provided the yuck factor doesn't get you.
http://www.backyardaquaponics.com/forum/viewtopic.php?f=18&t=2534&st=0&sk=t&sd=a

Hi again gokul, check out my cool new signature. Until the system has reached a 2:1 gravel volume to fish water volume ratio keep working to expand bed space. ->

Dave yes I saw the sig yesterday haha!
At first (you didn't have this but it was rumoured by other members that) it was "When in doubt, add more fish." (To increase nutes)
Then immediately after hearing this rumour about you, and seeing fish deaths in the forum thread, you put up a sig "When in doubt, add more plants."
Now this.



Maybe it will be, when in doubt, add more water next!

Steve, your remainder about quotes' overgrowth has worked!
Can you see any now?
yeah this is way better to read... i(we?) got carried away by BBCoding abilities

Yep, it's an evolution.

I considered "When in doubt, add more fish food." but thought that would really cause havoc!