Backyard Aquaponics
A place to discuss aquaponics

Sorry for the second post but I couldn't figure out how to edit my previous one.
this book has tons of useful stuff in it for just a couple of bucks.

http://www.buy.com/retail/product.asp?s ... caid=17902

it's available many places and it has the friction loss already calculated for up to 2 1/2 inch pipe.

Just a plug for a book I find myself using more than I though I would!!

I have had 16 LARGE Koi in the system for almost 2 months while construction has been going on and despite our best efforts we have not been able to kill a single fish. These fish are as tough as nails. As soon as I start getting Nitrites and Nitrates I'll whip them out and put in the actual tenants.

Temperature is an issue. It goes down to 17 deg water temp at night and up to 22 deg during the day at the moment so too hot for trout and too cold for Tilapia. We have decided to heat the water for 3-4 months and go with Tilapia, but plenty of work still.

Cheers

The resttriction is definately the 20 mm pipes ,, 3 X 20 mm pipes just do NOT have the flow of the single 50mm . PIE R squared ....., 50 mm pipe , R=25 so cross sectional area is 1,962mm , each 20 mmm pipe has 314mm. It would take at least 6 X 20mm pipes to flow the equal of 1 X 50mm.
As you are using 3 tubes coming out of the 50mm main pipe , I suggest 3 X 30mm would do the job.
The "T's" off's can remain 20mm.

What flow do you get from the 50mm pipe? Litres per hour ,, is that enough to flood the beds in the ammount of time yopu want?

I'd hate for you to replace the 20mm tubes then find that although flow increased substantially , you still cannot flood the beds fast enough.

Your bottleneck was the bit of 20mm pipe before the T-off. That pipe was taking ALL the water. 3x as much as the pipes after the T.
Q=v*A
where Q=flow rate (L/sec) v=velocity (m/sec) A=cross-sectional area.
The flow rate in the main pipe is 3x the pipes after the T-off.
In scenario 1 with the same pipe sizes, the flow velocity in the main pipe was 3x that of the minor pipes, so it was your limiting factor.
In scenario 2 the velocity is decreased by 6x in the main pipe (see chappo's post) and the water is going half the speed (velocity) through this section as it is in the minor pipes. Meaning less friction etc, so now the minor pipes are your limiting factor. Or maybe those spray bars

Does the water get that cold at night even inside the greenhouse in winter?

Well even so, 17 C being between 60 and 64 F, at least the Blue Tilapia that are common around here would survive that even if they didn't grow well during that time.

I expect a good little solar heating set up for the water could keep you pretty close to good temps for little energy. Good Luck with it and keep up the wonderful work!

Yeah, my Tilapia are OK down to even 10 deg C, but don't expect any growth. We are considering buying a heat pump to just tip it to over 20 deg C, but then I got thinking, seeing that this is supposed to be low-tech.

We have access to about 10 gazillion tons of sawdust, mmm.
We have access to a digger/loader, mmmm
Why don't we dig a long trench, run 40mm black pipe along the bottom, fill with sawdust, water and voila, won't we generate heat ???

Ideas? Comments?

OK, I have finished half of the growbeds, planted some test plants and introduced some bacteria from my home system to the GB's. I have performed a water test so that I have a base. Help with readings would be appreciated as I am colour blind.

Currently in the system (estimates only)

Water 7800L x 4 + sump 5000L = 36200
Gravel = 7200kg (half GB's filled and assuming 50/50 water/gravel)
Fish biomass = 64kg
Water temp = 20 deg.

Comments?

I'd call that near enough to zero ammonia and nitrite... maybe 10 nitrate... pH 6.5

Umm, the wife wants to know how the hell you are going to reach the plants in the middle?

I'm 7'6" tall so it's fine (jokes) The grow beds are 500mm wide so the most we'd have to stretch is 1m from the central asiles which is OK. Also they aren't very high.

Some images of growth. We must be doing something right as the strawberries are doing well and the cucumber and squash seeds came up within the week. We have decided to install a heat pump to get the water temps up to 28deg before the fingerlings arrive. It should arrive by Wednesday. We are also starting the algae pond next week.

Guess you could say this system is officially in "production".....

Look forward to seeing this in full growth synapto... reckon it'll be a ripper.

Reckon you could take a picture showing the whole lot now?

I'll try tomorrow, but it's difficult to get into one frame.

That's OK Synapto.... you're allowed three photos per post