Backyard Aquaponics
A place to discuss aquaponics

Look, I'm not trying to argue here, but I have less than 100 small fingerlings in a 1000l IBC, and the bottom is clean.

I had 50 tiny trout in a 1000l IBC, and the bottom was clean.

The only time the bottom of an IBC gets dirty is when there is only a couple of fish in it.

Unless I have special IBC's?

OBO, I think you just have special fish!!!!!!

As you said though, when you only have a couple fish in it, bottom collects some gunk.

See, fish are good for so many things. Providing food, Providing nutrients for plants, Serving for hours of entertainment, being excuses to spend hours with the AP system, and even cleaning the bottom of their tank!!!! "Honey I need more fish, the tank is getting gunky again" See!!!!

heh thats a good a reason as any to get more fish

Most AP systems I've seen here on this forum... are clean.... or near enough to it...

I reckon it must have something to do with the (continual) filtration of solids and suspended matter by the growbed media.....

And correct design... and feeding practices....

Maybe we should just stick with what works.....

that is, while it shows conservatism, quite alright with me
not a hair on my head (and I still have a few ) would think of trying to convince you to change a system that works fine for you.

But most of us here asking questions are in search not only of a good, but of the best possible, most versatile system, not just one that fits trout or catfish

and while building a new system one might just incorporate every improvement that is neither too expensive nor too complicated

a drain that takes the solids from the bottom is most definitely an improvement :
it will suit all fish species and remove solids quicker than a simple overflow
thus leading to less DO demands in the fish tank

and I see no arguments against it: the first one still has to come up

here we are talking about maybe the simplest of improvements:
1 extra m of tube and 1 extra tee and your system is adapted to all kinds of fish at all kinds of densities (within limits)

in a simple overflow the solids by definition have to swirl through the water column that the fish use to swim and live in
If anything this must be less healthy for the fish
(I'm not saying it is, but it surely cannot make the environment in which the fish live worse to avoid this)

swirling of the solids through the water column happens nowhere in nature except in rapid flowing waters (much more rapid than in AP)
Though trout and other species can survive in troubled water,
they will most probably do better if they don't have to swim through their own junk

but, as said, don't change your system for me
if you do, do it for yourself and for your fish

frank

I was being a little tongue in cheek Frank....


The point is Frank.... it's not new... conical bottom drain tanks have been around for donkeys years....

But most people can't afford purpose built conical tanks... and it's not the way that most people have implemented their systems... partly because it involves inline pumps, which are (usually) more expensive..and because the shape of such tanks generates issues regarding height in relation to other system components...


I don't think that anyone is really running a system that relies solely on a overflow standpipe Frank....

Those systems that only have a standpipe... do so merely to provide a method of maintaining a water level and catering for any "overflow" situation....

They remove solids by a combination of circular flow,(generated by water return), which sweeps the solids toward the centre... and a pump in the fish tank, that then sucks the solids out of the tank and deposits them into the growbeds...

Most other systems employ a Chift Pist arrangement, for various reasons... with, what was until recently called a "venturi siphon"....

Effective as..... (maybe not "efficient" as)



All of the existing designs cater quite well for any species Frank... can't understand why the species of fish is a "design" factor....



See above... but true to some extent... all fish activity, water return, oxygenation stirs up a degree of solids into suspension anyway...

The point I'm suggesting Frank is.... you really shouldn't have any significant degree of "solids" floating around in your tank anyway.......

Unless... you're chronically overfeeding ... or you're highly/over stocked....

The former is easily dealt with.... stop feeding your fish more than they need...

The latter.... well the existing methods seem to cater perfectly well for densities up to 6kg/100ltr... then, providing you have sufficient growbed capacity, there just isn't a problem....


IF... you want to exceed stocking densities beyond that... then yes, some method of solids removal is probably necessary....

But given the size of most peoples systems,likely size of their fish tanks and room available for growbed filtration capacity... it is really (IMO) imprudent to suggest that people exceed anything beyond a stocking density of 6kg/100ltr....

For no other reason alone... than such densities require a inversly proportional investment in management.... and/or cost to provide the necessary filtration capacity...

Here I do agree with you and what you're trying to acheive by suggesting methods of solids removal and the reasons you give....

But, most people just don't seem the have an issue as such.... because they aren't stocking beyond their capacity... and beyond their knowledge or ability to invest time in management...

Those that do... usually kill their fish...

I don't care what the (formerly named) venturi siphon is called.... Chift Pist is so simple and works so well.... as do the other tried and true system designs...

You shouldn't have a "solids" problem....


Now ... if the discussion is "how do we increase the stocking density".... then yep... beyond a certain density, a venturi siphon or a simple pump arrangement... may not be sufficient to remove enough/all the solids...

And other methods may need to be employed... whether they be bottom drain to settling tanks, airlift pumps to swirl seperators etc...

I have no problem with you attempting to refine the design of a system or a system component, thus improving it... or trying to implement higher stocking densities if that's what you wish to acheive...

But for the sake of most people who have limited time to manage their systems...

I prefer to advise them not to exceed a "safe" and "over-seeable" level of stocking density.... and implement a proven system design.... then solids shouldn't be a problem...

And given the small nature of most peoples system components... nor will other wtaer quality factors that might be impacted by the actual size of the equipment...

Push your densities in a small volume of water... without constant supervision and knowledge... then (for most people) you're well on the way to a fish kill....

Jeez, Rupert
you sure put an immense effort into not admitting that a system that sucks the solids off the bottom is better than one that does not
and that such a system is very simple to install
and that such a system only costs a fraction more
those are the only points I'm trying to make

three positive arguments that you in no way contradict in spite of your long contribution

your only counter argument is that fish might get killed if one doesn't manage one's system which is obvious

but that has nothing whatsoever to do with whether the solids are sucked from the bottom or not:
if you take too little time to manage your system (whatever system) you stand a good chance to kill the only fish in there
sucking solids from the bottom doesn't increase that risk, in fact it might be more forgiving

if one starts anew, one might as well take the best solution
what could possibly be against that?

frank

Seems we're losing something in the translation Frank...

I was pointing out that in fact almost without exception... that's exactly what everyone has/is doing.... and distributing the solids to the growbeds... and is indeed the "best" solution...

Whereas, you seemed to be suggesting that it would be better to employ a "bottom" drain.... and to remove as much of the solids as possible...

Then I suggested that the only reason to do so was (as you have often suggested) to allow for higher stocking densities...

I thought I'd been quite clear... that I didn't believe that running densities above a certain level was to be recommended to the vast majority of people... for the various good reasons....

And that solids should be retained and utilised within the growbeds....

And that, as such, was what the majority of established and successful AP systems and AP'ers were in reality doing... and was best for anyone "new" to do...




No arguement there at all Frank... that's exactly what I was saying.... I thought I was actually agreeing with much of what you said.... :mrgeen:

By all means refine what works, if you think it has benefit... otherwise, stick to what has been proven... is all I'm saying...

Said it before Frank... build it all into a system, and show us the relative gains....

When I can see it works and has obvious benefits, and is manageable... I'll happily recommend it to others... and probably adopt it myself....

must be my lack of understanding the englisshh , sorry for that

so may I conclude that you agree:
that a system that sucks the solids off the bottom is better than one that does not
and that such a system is very simple to install
and that such a system only costs a fraction more

those are the only points I'm trying to make

frank

Agreed Frank... didn't think there was really any other way to run a system .... other than bottom drain via inline pumps ....

If you return the flow to the top of the FT you 'overflow' from the bottom. If you return the flow to the bottom of the FT you overflow from the top.
Top overflows skim crap from the surface, bottom 'overflows' take crap from the bottom.
My 2 cents worth anyway

Thats the number 1 reason why I like the top overflow.

Well that puts me 180 degrees out of phase then - I am a bottom overflow enthusiast

there is no need for choosing:
why settle for one or the other if you can have the best of both worlds?

take a look at TCLynx' drawings, the version on the bottom:
viewtopic.php?f=1&t=4174&st=0&sk=t&sd=a

by having the horizontal pipe and the tee a certain dimension and the pipe to the bottom slightly less wide (or tapered at the end), the bottom of the thank will first start to suck the solids, and as the level in the tank rises, an overflow will start over the rim of the tee skimming the crap from the surface

to create this situation, the only thing you need is a pump that has a superior flow than the upflow through the pipe to the bottom

frank

sorry, tuned out 1000 words ago..................