Backyard Aquaponics
A place to discuss aquaponics

My First System.

I am planning for the preferred 2:1 ratio and have read that you should pump the volume of your FT every hour.
This makes sense but it would then mean that your GB's would only be half full each hour at a 2:1 system ratio.

Q. Does pumping the FT Vol to the GB's more than once an hour cause any issues with low levels of nutrients for your plants?

Q. A bathtub GB doing a F&D in two hours, I.E. Flooding up to Drain level in two hours and then draining over 10 mins.
IF it is possible to exclude environmental factors such as cold/hot, day/night, up/down and plant/fish types, would this be too slow? Would you need more information on my design to make a call on this?

Q. I will start with Goldfish at first as this is only a pilot plant. If I've one FT at 250 litres capacity and 4 GB's each at 250 litres capacity (Meaning around 400 to 500 litres of filtration) how many goldfish should I be looking at for my stock?

Cheers,
Sideshow Bob

P.S If this has already been covered, I could not find it.

With a 2:1 Grow bed to fish tank ratio, you need some method to deal with extra water in order to flood the grow beds without leaving your fish high and dry. As in say a sump tank.

Some people with little tiny systems will say pump for 15 minutes and then off for 15 to 30 minutes instead of the kinda standard 15/45. It all kinda depends on the situation. The important part is to flood and drain regularly during initial cycling to make sure the bacteria has a chance to work on the water yet still gets enough aeration to do it's job.

I'm not quite sure on the idea of a 2 hour flood then 10 minute drain. I'm not sure how you would effect such a thing unless you have some sort of automated valve on the grow bed drains and are using a very slow pump to fill the beds. Generally for a timed flood and drain, the drain time is going to be slower than the fill time when using stand pipes with holes. However, if you were talking about simply flooding the grow beds for 2 hours (letting the excess flow go over the top of the stand pipe) and then turning the pump off for 10 minutes, well I suppose you could do it that way but I don't really see the point. Most plants like a bit more dry time. Though C1 runs constant flood in his system and seems to like it.

As to how many fish. 3 kg per 100 liters of media and not more than 3 kg of fish in 50 liters of fish tank. Not entirely sure how to really equate that to gold fish though since you are probably not growing them out to plate size but maybe you pretend each fish is going to grow out to 500-1000 grams and base your numbers on that?

Damn that 2:1 ratio just keeps on cropping up all the time...

Every system is different sideshow, and there are really are so many variables, that timing of flood and drain might be alright.

hey side show bob..

are you using a sump?? if your gb's flow into a sump and you use a CHIFT PIST or CHOP system then the level of water in your fish tank stays the same...

there is plenty of designs on here for CHIFT PIST.

not sure if the 2 hour fill time of you ft's would be an issue to the plant roots being too wet and hence rotting in qld heat..

earthbound had a system running where the pump would run for say 1/2 hr then off.. and instead of siphons there was a stand pipe with a small hole in the bottom to drain the water out.. if i build another system i think this would be worth a try..

as for the nutrient levels.. they build up in the gb media..

Thank you for your information TC.

EB and ALH, hello!

I understand that there is a hundred different ways to skin the AP 'cat', that 2:1 has popped up in nearly every post I've read lately too so I am starting to see it in my dreams... not really.

OK, my system is based on a CHIFT PIST (I love writing that, it feels naughty!!) but with bigger ST and HT's so I can cut down my pumping times. I can make the flood and drain times quicker but that means more pumping, I was just adding up the rules of thumb written here, like 2:1, volume of FT once per hour etc.
My farm is completely on Solar power so keeping the pumping time down makes for a more efficient system and saves me running the genset!

I have read so much in the last six months that I feel like I'm in an overload situation. I am going to begin the system cycle when I get back from OS and will post photos and info as I go. If it works great! If it doesn't, back to the drawing board!!

Thanks for your time,

SB

I think you may need to take into account the GB media with your volume calculation. Your GB with media in it will only take around 40% water (from what I've read here, please correct me if I'm wrong) this means if both GB's are flooded it should be 80% of your FT volume... me thinks

Thats where it depends totally on the design of the system, a chipt pist with a large sump doesn't have a problem..