Backyard Aquaponics
A place to discuss aquaponics

I am pretty experienced with both systems in greenhouse container production and hydroponics but I am heading into this new (for me) production system.

I like ebb n flood but I am not sure I like the autosiphons, would prefer to drain via the pump back to the sump, however I will build an autosipon and give it a try. I also dont think I want to have another sump that dilutes the amount of nutrients in the water.

Are there big problems with the simple loop siphons systems?

I like the ebb n flood because I like the pulling in of the air when they drain.

However, the continuous flow also seems to be a very efficient system. It is very easy to put in O2 with a venturi so I guess O2 levels should be decent, I am going to use hydroton as a medium either way,

What sort of emitters are used for the continuous system? What sort of pressure are you hoping to obtain or do you just use holes in the pipe? Would you get even distribution of the water?

My grow bed is 4' x 8' x 10" deep, pressure treated lumber lined with butyl pond liner. The fish tank is a 100 gallon rubbermaid trough that can be filled to whatever level needed to match the desired fish ratio.

Maybe best to ask multiple q's in multiple theads, its raining here, do you at all worry about dilution or leaching the nutrients out of the growbeds?

cheers

peter

Hi Peter and Welcome!

First thing I will point out to you is that having extra water in an aquaponic system shouldn't not be looked at as a dilution of your system. It is not like Hydroponics where having a bigger reserve means you have to throw out more and replace it every so often. an extra reserve of water in an AP system simply means your system will be more stable.
(the only time a huge reserve of water in an AP system turns into a drag is if you need to salt to a rather high concentration in order to combat a disease attacking the fish. In which case one should have a quarantine system for new fish or sick fish before putting them into the general system.)

Anyway, For simple systems on this forum, most people go for flood and drain media beds. This can be done with pumps and timers (it is generally not a good idea to let the water backflow through your pump though) or with a continuously running pump and auto siphons. Loop siphons are great, I have many of them. Bell siphons also work. then there is a thing called a Flout which also works but takes up more space though it is very forgiving about flow rates which is great.

As to continuous trickle systems, These might be wonderful for the plants and I've done it in hydroponics systems but they are not as good in Aquaponic systesm. The problems are that emmitters or even holes in pipes tend to clog up with the solids and bioslime that are a big part of aquaponics. The other and even more important problem with trickle feed is that only a small portion of your media gets wetted and only the wetted media provides bio-filtration for your system. You want even wetting of the below surface media yet you kinda want to avoid much wetting of the top surface of the media. Now if your system is going to contain large separate biofilters and solids filters, then this doesn't really matter so much, but if you want your grow beds to provide your solids and bio-filtration, you should probably go flood and drain.

Some people prefer continuous flooded beds. The drawback to a continuously flooded media bed is that aeration is really tricky to provide and the volume of media usually doesn't provide as much bio-filtration as the same volume of flood and drain media. I've read some huge struggles some people have had trying to make this method work.

Now there are some very successful models of DWC systems out there using rafts for the plants. These systems have separate tanks to deal with bio-filtration and solids removal and require lots of aeration. I don't know of too many BYAPers doing these sort of systems but it appears they work well for large scale things like the University of the Virgin Islands or some members out in Hawaii. I have the impression these systems are good for green leafy production but might be more problematic for large plants that need lots of support and completely inappropriate for root crops since it involves growing in net pots suspended in foam rafts.

Welcome again and good luck

Thanks for your advise, i think I will go with the loop siphon and see how that works.

I am not sure I understand how additional water will not dilute the system. There is so much discussion about ratios of tank to gb that increasing the tank/sump changes the volume of water. So why even discuss the ratios?

Anyway, I do know its really about the amount of food and the percent protein in the food that generates the N and eventually the nitrates, so I guess I will go bigger, I also know from salt water reef tanks that nothing good happens fast or that more water decreases fluctuations.

I went to the International congress on Aquaponics in Mexico in October/November and talked extensively with James Rakocy from UVI about his system. I do really like deep float systems for most of my hydroponics. In fact I am registered to attend his short course next june.

I also meet Nick Savadov from Canada. His system is really impressive, as he uses a geotube to collect and compost the solids which come back to the system. His ec's can be upwards of 3 and can easily support tomatoes.

The weight of the tomatoes is not an issue anyway as you suspend supports from above that hold all the weight.

Checked the local fish market today, talipia is number 1, and they sell 60 pounds of catfish each week as well, so I am not sure what to grow.


Yipee this is going to be fun

TCLynx,

+1, as usual.
Anything else, Peter?

Oh, yes: "welcome aboard!"

hydrophillia,

tell me about your set up in sonoma..... I am not that far away .... going to berkeley after the 1st and may head up to marin to look at a truck,

cheers

peter

Sounds like you have done a bit of research.



As to the ratios, that is usually more about the fish load or feed load and how much bio-filter is needed to take care of that load so as not to kill your fish with ammonia or nitrite or clog up your system with too much solids.

Most of us don't actually worry too much about the exact amount of nutrient in the system for the plants as the exact level of nitrate in the system does not seem to correspond to plant growth since there are usually so many other factors involved and a brand new system is rarely as productive as a more mature system and some people have wonderful plant growth and no measurable nitrate as their systems seem to be perfectly balanced.

As to what kind of fish to grow... What kind of fish do you like? What kind of temperatures are you going to be able to maintain in your system? Tilapia might be a good choice if your water is likely to stay above 70 F year round. If the water temp is likely to be lower than that in winter, tilapia won't grow much while the water is cool and if the water is gonna get below 55 F, you risk the health and perhaps even the life of the fish. I have both tilapia and channel catfish, we like them both but trying to keep the water really warm for the tilapia is kinda a pain so we might not get any more of them in the future. Catfish like more aeration and grow a little slower but are otherwise pretty easy fish. There are other choices out there but these are the two I know about.

Havnt had a nitrate reading yet

Peter,

Four systems so far:
1) 10-month test of sand bed with twice daily flood/drain (hot tub and blue barrels). Raspberries, blueberries, rhubarb(grew huge!), parsley, and figs. Works well as concept: time to get serious!
2) 9-month-old indoor outdoor system (viewtopic.php?f=18&t=3620&start=0&st=0&sk=t&sd=a) (now split so indoor fish tank is warm: catfish and tilapia). Grow bed is in the shade until sun rises higher in April.
3) 6-month-old barrel system in ground for thermal buffering (now with only goldfish: winter temps are too low for tilapia). Doing well with kale, leeks, chives, cilantro, and random cool-weather seedlings.
4) 3-month-old monster integrated reflector system in greenhouse: 19'x4'x4' with about 900 gal of water under a 12" deep gravel bed with a reflector along north side to reflect southern winter sun for more heat and light.

I'll pm my contact info if you want to come up or talk...