Backyard Aquaponics
A place to discuss aquaponics

Can someone please explain to me the concept of a sump tank? I am very new to aquaponics and have started to read all the information that BYAP has on it's website, but can't seem to find any mention of what a sump tank is. In the IBC system BYAP setup on youtube (and in the IBC of aquaponics guide), there is no sump tank. So I am guessing it is not completely necessary? Thanks!

Hi Samuel and welcome to the forum. We sometimes use a sump tank, otherwise called a drain or fingerling tank in the event that the water cannot drain directly to the main fish tank. In my 5 bed system, for example - the height of the top of the fish tank is higher than the bottom of my growbeds. Therefore my growbeds drain to two separate tanks, before the water is pumped back to the main fish tank. A simple system would have the water directly drain to the main tank. In hindsight we would have possibly split my system for a variety of reasons such as the ability to use smaller pumps, hence less running costs and less risk if the power goes out and all the water drains to the main tanks. I'm not complaining though, my system is about to have its 5 year birthday and it has been an absolutely awesome 5 years of fish, fruits and flowers just to name a few! Hope this helps!

Yes, that pretty much answers my question. Thanks. So if you planned your system so that the height of the top your fish tank was lower than all of your growbeds (as if you buried your tank and had all the growbeds above ground), then a sump tank would be unnecessary? Therefore taking advantage of the benefits of gravity to save energy?

You got it Samuel

If you do flood and drain style grow beds, they keep the level of water in your fish tank constant.

I use a siphon from my fish tank to a sump tank with the pump because I don't want my messy catfish messing up my pump! I have to still vaccuum the main fish tank every now and then but it is a more controlled way of getting fish waste through my system.

A sump tank is also a store for "spare" water. If you had a 1000L FT and 4x500L GB filled with hydroton balls, you will pump about 600L of water out of the FT to simultaneously flood the GBs. This would only leave a small amount of water in the FT, so you could keep 600L spare water in a sump, pump this into the FT, which is built higher than the GBs so it can overflow into them, which flood and if the GBs are higher than the sump, the GBs can drain back to the sump. In this system the sump provides the water and hosts the pump, the water level in the FT remains the same, CHIFT PIST (or CHOP)

Thanks for all the replies. I guess my next question is, why would you NOT build your system to use gravity to save energy? Other than bunson's reply, I don't see why it would be necessary. Aquaponics is suppose to be a sustainable system and to not use the advantages of gravity in a system is kind of hypocritical to me Other than spacial limitations, I can't think of an excuse not to use this gravity factor.

With a constant flood system, would a sump tank ever be necessary other than to hold extra water?

All AP systems utilise gravity in one way or another.

No matter what configuration is chosen....the basics remain.

Fish tank, fish, pump, grow bed/DWC/NFT.

Obviously there is many ways to get the same result and there have been many trials on these different systems and what and how they work and how they perform.

A sump tank can be used in all types of configurations (including CF) and its use in these configuration differ from system to system.

To answer your question, yes, it may be nessesary to use a sump with a system run CF so the GB's can be set at a lower height than the FT.

There is nothing hypocritical......you just dont understand system design yet.

As has been mentioned too many times recently, the design of the system is going to be commensurate with the desires and wishes of the system owner, built and operated within a set of boundaries and limitations; different people have different needs, assets and limitations hence no one design (or even design philosophy) suits everyone.

So long as the GB is above the FT, whilst the system is fully flooded, no, otherwise, maybe.

What if you ever needed to do some maintenance of a constant flood system, what would you do with the water? Having a sump available, although rarely used, might make more sense rather than using buckets or flushing the water to drains, it just depends on the design of the system...

A sump or tank of spare water can come in handy from time to time.

I understand my knowledge of system designs and aquaponics is very limited at this point, but as the poster below you mentioned (I'm not sure how to double quote), each system is designed to the needs/wants/limitations of space of the owner. Therefore, can't you see how some systems ARE hypocritical? What I mean by that is that there are always ways to utilize the gravity factor (i.e. by burying FT), but in the end the choice is with the system designer/owner. Sorry, I might be playing too much of the devils advocate here.

Does anyone capture rain water and use that in their systems instead of from the tap? I feel like as long as it's not running off of a toxic roof material and if it is running off into a clean barrel(s), it would be more $ saved and in term, more sustainable.

All good, Im up for debate tonight.

Your statement was that to not use gravity in a AP system to favour energy consumption is hypocritical..... because, AP is considered sustainable.

Ok, as I mentioned, most AP systems/configurations use gravity..... its costly to set up without it. You dont need to bury the FT to utilise gravity (this is my point that your design knowledge is foreign), sure there are instances where needs/wants/limitations drive someone to incorporate a sump tank but this doesnt always pivot...... on the use of a sump for gravitational purposes.

Sumps used in AP dont always have something to do with gravitation or energy consumption.

So, no I dont see the hypocrosy.

The point of my sump is to use gravity! My ONE pump is in my sump, it pumps up to my fish tank, which floods into the pipes that drain into my grow beds, then siphons, which use gravity too, drain my grow beds into the sump. 100 watts of energy consumption.

Gravity at work:

Sometimes gravity cannot do everything...