Backyard Aquaponics
A place to discuss aquaponics

I am a semi-retired engineer - lets not work so hard! What would be the purpose of the sump tank and why not include its capacity for the fish?

I do realize (and did at the beginning) that one of the reason for the perceived murkiness by me is that there is more than one way to skin this cat. But, the basic system remains the same, the implementation becomes different.

One of the keys for me will be to understand which variables can be bent - for example - if the amount of substrate is too little - it is assumed that the fish will die eventually due to a build of of poisons that should have been removed - but what if you go the other way? It really isn't the water amount that defines the beds - but the amount of fish. Obviously you need enough water to flood - but it is the waste products of the fish that produce the need for substrate - correct?

And, the climate is going to effect this - cooler water results in slower growth - slower growth results in less toxins in the water, etc. Less toxins in the water mean less substrate OR less growth in your plants.

So - back to the basics, sounds like get a small system going and adjust for my local conditions. Any recommendations on a link to a basic system the size we are talking? Or would I be better off just going for it? I have more than enough resources to build this size of system.

This sort of question lead to the concept of maintaining a constant height in the fish tank and a constant pumped flow back to tank from a sump arrangement.....

Go searching for a "CHIFT PIST" system... or go find "Ellkaybee"'s system thread.......

or mine or Michael Ferrini's :-)

CRTD have a look at these threads for summaries of some small and medium systems:

http://www.backyardaquaponics.com/forum ... php?t=1618
http://www.backyardaquaponics.com/forum ... php?t=1617

Explains a lot. I don't even factor in water - we live in a rainforest after all. However, having to add water would dilute the closed system which probably would reduce the growth of the plants.

There are float values that don't limit flow - it is pretty easy to design a float that as a tank fills, the outflow tube is shutoff.

But, flood / drain is a very simple system to implement and there is no good reason not to go that way especially since you all probably have knocked most of the bugs out already.

the sump is to allow a constant height in fish tank (CHIFT) often with CHIFT goes PIST (Pump in sump tank)
If your fish tanks are at the top of your system, draining into GB and then to sump, your sump pump will not have to handle solids, having only filtered water in it.
To reduce mosquitos, a couple of fish are usually added to the sump, but not many, as this tank will fluctuate from almost empty to full.


Correct, this is a concept that many ppl have trouble with.
You need to decide what your limiting factor is, growbeds, fish tanks of fish. Whatever you have the least of governs your system.
If you only need x kg of fish, then match your FT and GB to the weight of fish. If you are limited to FT size and wish to maximise your system, then match your GB and fish to that.
IMHO it is best to have excess water. Excess water gives your system a certain stability. Things change more slowly, so you can notice them changing. Down side is: when you notice, and correct, they also change more slowly back to good health...
AP may be simple, but it's still an art if not a science.

Nice looking systems everyone - I think I got it. Pictures are worth a thousand posts after all.

In reality your sump will end up with quite a lot of solids in it - albeit fine solids. Solids that eventually make their way out of the grow-beds and into the sump will tend to accumulate there and not be pumped back to the tank - except those around the pump. The pump is normally a smaller less powerfull one than those that are used for non continuously running systems - this is why the accumulation of solids tends to occur in the sump. I reckon this is a good thing - because they end up devoid of any nutrients are are easy to remove because they are in the sump. I have no fish in the sump due to small amount of water that can be in there on the flood cycle and because of these solids.

Having said all this - I've not ever removed the solids from my sump. I must do this soon - because in parts they would have to be close to 10cm deep

So is almost all engineering! I have always liked an evolutionary approach - start off small and experiment and adjust - as you develop more and more experience, you can adjust - but at the beginning, keep it simple.

The problem is of course, as you get older with more resources, you idea of "small" changes.

Good idea on the sump having something that likes mosquitos - I don't want to create a Denque breeding ground.

Creating a system with more water allows the extra water to buffer - therefore it is safe to assume that the fish are the fragile part of the system - manage for the fish.

It might be a good idea for be do design a drain on the sump so that if it does get dirty, just open up the drain and hose it out.

We do have a dry season for 3 to 4 months a year, but we have a very good spring so we are never without water (unless the system breaks of course).

Didn't you say you were in software eng? Evolution is like entropy in code. We hate it. HATE HATE HATE. Evolved code is almost pure evil... I'm from the get it right from the start side of the fence, and so is my employer.
Re fragile fish and water buffer: yes

That depends on the size of your sump in relation to your fish tanks and beds. My sump (110gallon) is larger than my fish tanks (total 60gallon)and the air space in the media of my growbeds(4 beds around 8 each=32gallon)
very little difference in sump water level when all the beds are full only 32 gallons down from the 110 ~rarely are all the beds flooded simultaneously.

CRTD - tis not through difficulty but laziness that I have not cleaned it out. I actually do have a drain on the sump - but instead will probably turn the pump off one day when nearly empty (due to it being on fill cycle and ready for a top up as well) and bucket out the crap and put it on my dirt garden. Is bound to still have some good stuff in it that I don't want to go to waste.

Grasshopper - do you not believe in future versions? I am not referring to not designing - just not trying to be everything all at once. There are many ideas that end up on the scrap heap because on paper they are good - but after Beta - the real problems show up.

Evolution is not entropy - entropy is what happens when you never change your code and the OS keeps changing around it. Evolution is the idea you start with a prototype and scrap it - and then build what you want after you tested all your ideas.

You might not want to argue software engineering with someone who did it longer than you been alive... But if you wish to - have at it.

Sorry - I didn't mean you, I meant "note to self - add a drainage for sump" I could forget such a thing for sure.

hehehehe fair point old fella :-)
future versions of course. Modular applications yes. Where I work the word 'evolution' or evolved code, rather than evolved software is used to describe, nice code, that became spaghetti due to a number of foolish upgrade requirements by the customer, that were not in the initial design and require nasty obfuscated (love that word!) work-arounds...