Need Help Settling A Disagreement-Sump Tanks

[Darlene Cerullo]

Hello everyone! I recently finished Sylvia's Aquaponic Gardening book and feel empowered to make my own system. My goal is to eventually have an Urban Farm using Aquaponics, but I would like to start on a small scale first. I have about 500 SQFT of warehouse space at my disposal (lucky me!)

Our system will be a hybrid system--we will integrate media beds and DWC rafts. The water will be gravity fed from the fish tank to the media bed then to the DWC. Then at the end of the DWC there will be a pump (or sump w/ a pump?) sending the water back to the fish tank. 

My question is this: can we pump the water back into the fish tank using a pool pump or do we need to utilize a sump tank? I am of the belief that we need a sump tank, but my business partner does not agree! I need a very good argument for why we need a sump tank--any suggestions?? Thank you :)

[Pieter Swanevelder]

A sump tank has benefits in operation/maintenance.
- rather the sump tank run dry than the ft or dwc trough.
- if you've got more than one flow line - you can easily isolate part of the system for maintenance
- the more water volume the more stable the system
- easier to hook up more flow lines if you want to expand

Negative - needs space - not always able to go down in ground.

[Darlene Cerullo]

Got it! Ok so if we go with a 1:1 GB to FT ratio, we don't necessarily need a sump tank, but it's good to have. Thank you Pieter and Ryan for your input!! One debate put to rest, I'm sure many more to come :)

[Pieter Swanevelder]

gb implies ebb & flow - so you'll either require variable speed pump or sump tank to keep water level in dwc bed sane height.

do you have drawing of your proposed system with dimensions, flow rates?

[Darlene Cerullo]

Hi Pieter, thank you so much for taking interest in our system design. Attached is a little hand drawn layout. I'm thinking-500 gallon fish tank, 12' x 4' MB, 24' by 4' DWC. I know my fish tank should be 1000 gallons, but I just don't think I can fit that in the space so I sized down to 500. Do you think that will be okay? Also, I'm not sure how to calculate the flow rates--that's one of the main things I'm concerned about. I was planning to have a stand pipe in the FT feeding the MB and then the MB would have 3 bell siphons, evenly spaced. Then the DWC would just drain out at the end. Any suggestions? Thanks again for your help!!!

[Pieter Swanevelder]

Ok -

If you're starting out - maybe visit a few set-ups in the vicinity? Always good to hear/see first hand from other people.

The area between DWC and Pump not clear? photo clipped? depth of GB & DWC? Also look at accessibility - i.e. 4ft dwc width - will you be able to reach all the way over with plants growing or is it better to have access from other side as well? Maybe split dwc with top and bottom shelve? available light?

also draw the system in profile - to give you an indication of height differences. (  a sanity check is to draw the team's height in as well to see if you can reach every thing)

Your pump flow rate is usually determine as minimum 1 FT volume per hour - ( is mostly a function of your fish stocking density and plant growth ). i.e 500gal/hour. Your other streams must add up to this (conservation of mass flow)

Suggest separate your GB into 3 so that each Bell Siphon is working on it's own volume.

Also note that your DWC needs to be able to hold enough water to keep the pump running to fill your GB for BS's to trigger (if no sump is used) if you use a timed set up - with valves controlling the water inflow to 3x GB this could be changed to one GB+a bit volume.

[Darlene Cerullo]

Hi Peter!! I apologize in the delay. Thank you, again, for your insight--it much appreciated!

We did try to set up visits of other aquaponics systems that are in our area but so far we have not had any luck. Everyone has been very secretive/hush hush about their operation. If you know of anyone who is open minded in the Philadelphia area, please let me know!

However, we did speak with Ken Armstrong at Ouroboros Farms in California about his set up, which was very useful. I guess at this point we will be doing our best with what we have read/watched on YouTube :)

The DWC & GB will both be 12" deep. There is 3' on either side of the GB and 3' on one side of the DWC and 1' on the other side. Ideally, I would want more, but this is all the space we have. I think this will be sufficient since we can always pull the rafts out of the troughs if we need to check on the plants or harvest.

We have already taken into considerations the heights of the beds to ensure we can reach everything. My business partner is working on a CAD sketch now so we will have a more 3D look at the layout soon.

For 48 sqft of MB--do you think 1 Bell Siphon is enough? Should I do that instead of separating it into 3 separate beds?

Also, could you clarify your last paragraph--this one confused me a little:

Also note that your DWC needs to be able to hold enough water to keep the pump running to fill your GB for BS's to trigger (if no sump is used) if you use a timed set up - with valves controlling the water inflow to 3x GB this could be changed to one GB+a bit volume.

Thanks again!!

[Pieter Swanevelder]

Hi Darlene

Look up Upstart Farmers - https://www.upstartfarmers.com/- if you consider commercial system later - there is a few systems going in the Philadelphia region (<50km) - I"m sure they'll be willing to show you around. The site also has a wealth of information.

The table below and attached figures refer

The Bell Siphon discharge when triggered - as your growbeds inflow and out flow rates differ - there will be times when

your growbeds will be full (DWC in eb) and when GB are all empty - So your DWC level will fluctuate between 12" and 15.3" for total discharge and 12" and 13.3" for controlled system - if this is good or bad for DWC I don't know. but you need to make provision for the volume of water.

	w	l	h	V
				[m^3]
FishTank				1.89
Fill Factor	0.5
GB	4'	12'	12"
	1.21	3.657	0.3	1.33	0.66
GB A	4'	4'	12"
	1.21	1.21	0.3	0.44	0.22
GB B	4'	4'	12"
	1.21	1.21	0.3	0.44	0.22
GB C	4'	4'	12"
	1.21	1.21	0.3	0.44	0.22
DWC	4'	24'	12"
	1.21	7.32	0.3	2.66
Empty GB - all water in DWC				DWC+GB
DWC	4'	24'	15.30
	1.21	7.32	0.37	3.32	3.32
Empty one GB -  valve system DWC				DWC+GB A
DWC	4'	24'	13.27
	1.21	7.32	0.33	2.88	2.88

[Darlene Cerullo]

Awesome, thank you Pieter! We have actually now changed our system to a CHOP 2 so we are using gravity to return the water from the DWC & MB to the sump. Yes, I convinced my partner to put in a sump! Thank you for all your advise--we are starting construction now. I'll send you some updates as they come :)

[Pieter Swanevelder]

"alea iacta est" - good luck with the buikd!

an interesting read

https://university.upstartfarmers.com/blog/commercial-hydroponics-s...

[Jeff S]

Darlene, I admire your enthusiasm. However, I would suggest starting out even smaller to get a better understanding of what you want. The bigger you start the harder and more expensive changes are. My system is 1 330 gallon IBC fish tank, 2 12" IBC media beds, and 1 IBC DWC bed. Been at it for about 3 years now and have learned a lot. If I were to go larger I have a good understanding of what would work best for me now. Everyone has their own preferences and you will develop your own and as I said change is easier with a smaller system. Pieter has been giving you some good advice and there's a lot more out there so go slow.

[Yaacov Levi]

What did you come up with?

I would use the sump pump, which I do.

[Darlene Cerullo]

Hello everyone! My business partner and I went to a great seminar in North Carolina to learn about commercial aquaponics. Our system is now up and running-we are currently in the cycling process with about 80 tilapia. Yaacov, we have a 230 gallon sump tank that is in the ground. Our pump pulls from a triple check valve that is in the sump tank. Approximately 75% of the water is then pumped to the fish tanks and the other 25% goes to the grow beds. Everything is working great! Thanks everyone for all the info. I will upload some pictures asap!