Backyard Aquaponics
A place to discuss aquaponics

Well, I'm jealous!!! Really, Snaptoman, it looks very nice- you should be proud.

Market research is the key ..... no use growing something that sells for 1 cent a kilo.
I know Okra grows very well and in most markets returns a resonable price.
Don't forget to push the "organic" side of things ( organic = more money),, you may well not be certified as organic but the system itself is most certainly compliable.
Alkso think about some of the more expensive things that are harder to grow in dirt,,,for me in Thailand dirt grown cauliflowers etc are not very good because of the heat ,, I'll be pumping from the bottom of the lake/ pond , so will have better control over heat.

Synaptoman wrote this on his website-
"I am feeling extremely ill from inhaling so much PVC dust as well as PVC fumes from the plastic welding. My chest is tight and my throat is very sore. This stuff is highly toxic and I have got to try to be more careful next week."

Are you feeling better? You really should be using some sort of safety equipment. That stuff can be nasty, especially melting plastic!

Also I wanted to comment on the upgraded drain pipe- a bigger size is better, not only for root cleaning but should help with better drainage as well. If you still have problems getting roots out, purchase a new manual drain cleaning snake and use it exclusively for that purpose only- you don't want any cross contamination from sewage.
A couple of questions though- it looks like you're using sprayers to feed the water into the grow beds, are you concerned that they may clog since you don't have a pre-filter? Also, how come the sprayers are located right near the drain pipes? Just wondering if there was any particular reason.

Angie, yes, I am feeling better. I am using a full mask now for the welding and thankfully all of the grinding is finished. The 20mm spraybars should be OK as I use even smaller sizes on my other system and they just need the occasional rinse out. As far as the placement of the spray bars, no particular reason why they are so close (about 150mm actually) I just wanted 3 spraybars and 3 drains so when they were evenly spaced they just ended up close to each other. I figured being flood and drain, the water would all end up at the flood line anyway so where I put it in wouldn't make any difference.

I had an interesting day yesterday running water from one tank to 1/4 of the growbeds. Gravity fed it takes about 1 hour to fill to the flood line. The reason this is so slow is that the central drain in the pond is 80mm. It then reduces to 50mm outsode of the pond and then reduces again to the 20mm lines to the spraybars. I wish I could get it to flood a little quicker. After the pump goes off it continues to flood for about 20 minutes (because the water level in the pond rose way above the standpipe) and then the drain starts. This takes about an hour. I have set the timer to 1 hour on and 2 hours off and will test for a few days.

Cheers

Twice as many nozzles would halve the time ,, sorry to be the bearer of bad news , I know you've put a LOT of work into this. But more nozzles is surely less work than changing all the pipes. wait a minute ,, what is the flow rate of the nozzles and how many nozzles per 20mm pipe ???? No use using more nozzles if the pipe is under-size.

I just read back a few pages and i think I found why this was not picked up earlier ,, there was the mention of 2 X 3/4 horse pumps , I think many assume these where to supply the pressure to those 20 mm pipes for placing water INTO the grow beds. Now that i read a little more cafrefully those 2 X 3/4 horse pumps are to return from sump to fish.
20 mm under gravity is not going to give you a quick fill time. If you have done near all the plumbing you won't want to hear that ..... a high presuure ( high head) pump may halve your fill time ( at BEST). But bigger 40mm pipes would reduce fill time to 25 % of what it is now without a pump).

Looking back at the pics ,, I can't believe no one, including myself , didn't picked up this obvious undersizing ,, pictures just aren't the same as real life,,, if I saw that live I'd have immediately said NAHHH that not big enough.

I agree with Chappo. Use 40 or 50mm PVC (rigid pipe helps to reduce pipe losses) opening directly onto the gravel - no spray heads unless there's a reason I'm not seeing. Pretty sure spray heads will clog as well as being slow.

Two *should* be enough, placed midway between the drains to stop the water taking a short path straight down the drain. And chappo's right again, adding more outlets won't make any difference if the pipe is running at capacity.

Maybe this is a potential limitation of CHIFT PIST systems, but I'm sure it's one that can be conquered.
Remember that doubling the size of the pipe quadruples the cross-sectional area.

-if in doubt use bigger pipes-

Have you tried simply removing some of the spray heads and see how much faster it fills without that restriction? Most of my grow beds just fill from one point with only a ball valve or sometimes nothing to restrict flow. So far things seem to work well but I am using auto siphons of flouts to drain all but two of my beds.

I suspect that you may well be near the capacity of the pipe but you can quickly find out if you remove the spray heads and test again. If you are at capacity, you will see no real change in fill time but if the spray heads were restricting things, you should see the fill time get much faster.

Wait, are those actually spray heads or just simply valves? If they are just valves, scratch my last post. Your problem is probably that the small pipe can't deliver enough flow under only minimal gravity pressue.

Where ever I am gravity feeding a long distance with little fall, I go way over size on the pipe.

Thanks for the suggestions. I am intrigued by this problem, and not being an hydraulic technician I just fiddled around with various scenarios. Help me understand this please.

Scenario #1

Water flows by gravity from the tank through a 50mm pipe. As close as I can get to the GB's I reduce this to 20mm and then T it off in 3 directions with 20mm T's to fill 6 GB's.

Scenario #2

Water flows by gravity from the tank through a 50mm pipe. I T it in 3 different directions with 50mm T's and pipe. and THEN reduce to 20mm. ie I use 3 x 50 to 20 reducers instead of one.

Guess what? Scenario #2 delivers more water than #1. My problem is solved but I'd like to know WHY ???

Attached an image of Scenario #2. (T with 50 and THEN reduce to 20).

Also attached my first plant in this system, a strawberry.

Its kind of like a highway. If the road is 4 lanes wide(main pipe) and you reduce to one lane then all the cars have to slowdown and work them selves into a single lane. On the other hand when you split to 3 separate lanes then traffic moves along much better..

Also, smaller tubes have more surface area per volume so they also have higher resistance to flow.

As for hydraulics, you were trying to push a lot of water through a small line. For the water flow to stay the same in the small line(s) as it is inside the large line you would have to have much more pressure to move the same volume of water through the large and small lines; which you do not have using gravity feed...

Simply put, larger pipe allows more flow at a given pressure. Keeping the pipe size larger until after you branch will allow more flow to each bed.

I'm glad you solved the problem.

Yay Plants



Whens it fish time?

There are some great online Fire Department (Fire Brigade)Driver Pump Operator (Chauffeur) classes. They teach enough hydraulics and pump theory to get your feet wet. Yes I know it's dealing with larger amounts of water and pressure but it can be scaled down. The coefficients are out there for even the smaller pipes. Give a little knowledge of the theory and formula you can calculate the friction loss of a given length at whatever pressure and or volume. Hope this helps!!