Backyard Aquaponics
A place to discuss aquaponics

No. The job of biofilter is relatively minor. That is why the uni system could principally rely on the plant roots in the DWC to do the job of bio filtration. The role of GBs is not even solids filtration. If it where then the head loss through a FnD bed would be an equal con with the ramp (slide might be a better word) filter we have just been discussing.Rather it is to provide a place and a means to deliver enough oxygen to the biota that process the solids over time.

The research done in the feild of wastewater treatment has shown that the principal limiting factor in solids processing is the availability of oxygen. FnD GBs are very good at this because they keep the habitat for the solids processing organisms wet and allow them to absorb oxygen from the air rather than the water. Other forms of waste processing technology like MTs require more energy because they must have air pumped into them.


The theory based on Tom's experience is that when your GBs are 300 mm deep you have enough growing area to deal with the nutrients from the fish in an appropriately stocked FT.

My theory is that you need a certain volume of gravel to process a certain load of solids. This means that if you want a certain amount of fish you need a certain volume of gravel or other media. To use the you need a certain area of plant production. This means that it doesn't matter to what density your tank is stock ed as long as you have enough volume of GBs. If you gave that volume of GBs in a cube then you need X2 of DWC, NFT or equivalent to make use of the nutrients.

My beds are being operated at a 3:1 ratio and they were showing only some clogging at the inlet to the GBs. Bear in mind though that that there are about 340 trout around 500g supplying the waste into the one point of 2 GBs only 1m wide 1m long averaging 0.75m deep.

I don't know that 3:1 or 6:1 is better it may just be more expensive. I imagine that once more research is done it will be found that different volumes of gravel will be required for different protein feed contents and operating temperatures. In fact we know this to be the case but all the information is derived from the waste treatment industry and they don't operate their beds anywhere like the way we do.



In the waste water treatment industry they often do periodically "rest" beds for days or even weeks at a time. Systems that are allowed to dry out I imagine would have very different ecosystems. AP systems I imagine would have similar range of organisms if operated side by side no matter how they were operated but what is likely to be significantly different is the population densities of different organisms. Different systems in different locations are likely to have very different biota. For example the Hawaii guys get a range of crustaceans that I've never seen in my system.

The way you see AP systems run on here we don't have dry periods. What we have are a while stack of moist surfaces exposed to air. The water covering everything in a film in the media gets depleted of O2 the O2 can be immediately replaced in the water film from the air.

An experiment I want to run is to establish a really deep GB (like 2m) and over the years run a series of tests on it. For example monitor O2 depletion while flooded and also see if there is a measure able O2 depletion or CO2 production while drained.

In my experience it's not the rock that is expensive it s what you stock it in.
The curve increases the amount of water that makes it through the screen. If the solids are going to a MT you might not care because the water is still staying within the system.
In your case you probably want to be exporting the solids so you probably do care about reducing your water use

I completely disagree.. no matter what mineralization rate you are it.. I will in no way be faster them the rate in which your GB is being replenish with solids from the fishes when you are not filtering.. I always say I have 2" boulders and that became clogged after 1.5yrs... I don't ever want to go back to cleaning on my GB ever again.. a filter is easier to clean. Secondly more solids don't amount to better growth.. we all can stand fast to this and agree.. proper mineralization is key.. and there is too much variables to consider when forcing a system to grow plants and fishes and bacteria and micro organism in the same system within the same pH... thats an impossible task.. but in removing the solids and breaking them offline.. a better product can be made in a much shorter time line as well as decreases the possibility of your Gb being clogged..

Lol I thank you for putting this statement right after the previous post... Keyword BOD.. what is BOD..? what causes it to increase..? when it increases how does it affect the system its apart of.? Pure water itself has a max Oxygen saturation point at a specific temperature... it doesn't matter if it 1 Gal or 1 million Gal the saturation % remains the same... the same applies to F&D and CF to DWC.. Oxygen saturation will not increase between the different GB... but why do ppl believe the F&D has better aeration than the other.. In reality it does have better aeration than the rest.. not due to its drainage.. be due to it decreased % of going anaerobic.. Which leads me back to BOD... BOD IS THE MAIN REASON PEOPLE FILTER WATER before it goes into GB like DWC and CF..why you ask.? because you don't want solids entering into you grow bed which puts a biological load on you GB media.. its already converting ammonia to nitrates which O2 consumption increases as ammonia increases... now you are forcing the GB now to mineralize solids waste which eats up more of your Dissolved O2... F&D compensate for this lossed O2 in its drainage cycle.. but the main drawback is that during this cycle less ammonia is able to touch all the wetted surface of the media and results in it going back into your FT... CF will convert more ammonia than F&D if it wasn't limited by O2.. so how do we improve O2 amount in CF bed without adding additional aeration.. decrease BOD by decreasing Solids into GB and limited the GB to conversion of Dissolved waste not solid waste...and everything should be fine..

MERRY CHRISTMAS EVERYONE..

Aww thats so sweet of you to say.. I agreed there wasn't anything on the net to go with.. so most of our discussion were strictly experimental and isn't any rule of thumb.. but we did find alot of break thru and enjoy ever step of the way... Can't let that thread die..

In my experience it's not the rock that is expensive it s what you stock it in.
The curve increases the amount of water that makes it through the screen. If the solids are going to a MT you might not care because the water is still staying within the system.
In your case you probably want to be exporting the solids so you probably do care about reducing your water use

Cookie,

I don't think the thread is going to die for quite some time especially since you 2 have added some new toys to your arsenal. And I thank you too for your experiments as they have and will continue to help anyone who passes the thread and is teachable. Keep up the good work For any one who doesn't know what we are talking about here is a shameless plug. viewtopic.php?f=18&t=20661

Stu,

I know that I should get your comment " it's not the rock that is expensive it s what you stock it in". It maybe that I am tired but it alludes me at this moment. As my GBs were much cheaper than the rock that fills them. The question that I have is why would I want to export the solids? If I needed to build another Identical dual DWC setup I will. Plus raising in pots or Dutch buckets is an option if I have any grass that I can still se in the backyard. Seriously I want to send about a most of the waste to the GBs, The rest should go to a MT or 2 if needed. So I can get the best use out of it. If I mineralize more than my system can handle, being put back into it. And I have no more yard for expansion. My neighbor could use good fertilizer for his all dirt garden.

Stu sry for coming down so hard on you in this post.. I reread it and I found myself be a big fool especially seeing the season of caring... I in no way wanted to judge you and I completely accept and encourage all the free and detailed inputs you share.. I think I was a bit hungry before.. hence the bad temperament.. but I was wrong for the way I portrayed my views.. its not gospel so I shouldn't force it onto people... sry for that and seasons greeting.

Thanks for the thanks.. but I cannot accept it.. I learnt alot from this forum and all the information I portrayed is what I developed learning here.. I will be wrong of me to say it was mine or any singular group... even when we learn from someone else mistakes we still must be thankful for them to put aside their pride and post up their failure for us to learn from.. I believe they are the true teacher because they are sincere in that motives and don't do it for fame.. so forida don't limit yourself to one thread.. there are loads of threads to go thru here.. you just go to put in the effort to find them.. I'll suggest start looking at other members system threads..

Cookie,

I in no way limit myself to just your thread. My posts can prove this, as my posts can prove this. I have learned a lot of very useful information from many other people on this forum. There is more info hidden in the threads of this site than I will ever have the time to dig out. I was merely stating that your thread is showing some groundbreaking experiments. Ones that we can learn a lot from. As for my opinion which I had stated. At the moment you guys are appear to be at the top of the MT game. It maybe next month someone else takes your experiments and improves on them. That being said. If I wanted to know drag coefficients of the pipework in my system. Or how to make the circulatory system more efficient. You would not be the one I turned to. I would defiantly go to the forums math magician Stu. I was just giving credit were I felt it was due. As we all owe this forum a debt of gratitude for helping us learn both from each others mistakes and successes. And since we have, no one can really get a fat head. I just believe that we can all further this hobby. Better by focusing the energy on the spear point. Currently piercing the unknown and old beliefs. No mater what field of the whole aquaponics game it is in.

[quote="floridafishin"]Stu,

"Seriously I want to send about a most of the waste to the GBs, The rest should go to a MT or 2 if needed."

This statement was proof that I was tired. It should have stated " I want to send about 1/8 of the smallest solid waste to the GBs, the rest to a MT or 2 if needed."
Sorry for the confusion hope this clears it up.

As far as you routing most of solids to mt and a small amount to growbeds makes more sense. [WINKING FACE]

Swede,

Thanks I'm learning. It must have sounded like I was braindead Especially after talking after asking questions on the MT thread. I read it again after some sleep and decided I better change my wording. Because somehow I left ALOT out.

You make a good point on the difference... ok I agree with you.. carry on..