Backyard Aquaponics
A place to discuss aquaponics

With regards to head, aside from actual vertical lift, diameter and length of pipe must also be considered. I know this from years of research into saltwater aquariums (something I still haven't had the balls to commit to...one day...). As much as one might think, "Sweet, 8000lph at 4m head, well I'm only pumping 1m to my tank", if the pipe is only 20mm, this may create enough back pressure for the pump to actually see 3m of head and therefore draw more power (numbers pulled from the air for argument sake).

I like the look of both the pumps linked here. I might have a closer look at Guppy's and also Age of Aquariums. Both usually have something cost effective to offer.

Yea Dui is correct, more head - more power is needed.

Absolutely correct and 90 degree bends (or in fact any angle bends) also effect pump load and therefore power usage and flow.

I finally got my power usage meter on ebay.
So contrary to what is intuitive and also agreeing to points on another thread somewhere..
A pump will use LESS power for the following reasons
1. Bigger head
2. MORE restriction
3. Anything that REDUCES the water flow.

It seems counter intuitive but the principle is the same as when you put your hand over a vacuum cleaner. What happens is that when you restrict the flow the pump actually has LESS work to do and therefore uses less power. When you put your hand over the vacuum cleaner the moter revs up, or spins FASTER. Why? Because it has less load, and less load means it can spin faster.

I have evidence as well, only in verbal form.
My old 200W ebay pump:
-running with only a short length of hose (max water flow) 135W
-Pumping up to my GB through lots of little holes 100W
-My finger jammed in the pipe so ZERO flow 85W

New Jabao eco pump (awesome pump)
-running with just included fittings (full flow) 48.5W
-running with my finger jammed in the end (ZERO flow) 44W

of course for the SAME FLOW RATE at a higher head you will need more power, thats obvious. But that is not using the same pump, you just need a bigger more power hungry pump.
With the same pump at a higher head, your flow rate decreases (of course) and the power consumption also decreases (not so obvious)

QED

Interesting.
The above is definitely not true for a DC motor.
I thought I might be going insane, so I just tried it on the bench.
630mW unloaded, 987mW gently loaded, completely stopped it blew the fuse in the DVM

So Watt's (oh no, can't believe I just said that) different with a mains AC motor?
We should probably take this out of Ghengis' Thread, sorry for the hi-jack !

You're right in that when you load the motor it draws more current.
What I am saying is that reducing the flow rate of the pump by adding head etc reduces the load on the motor not increases it..
So try it with a DC pump
Yes sorry for the hijack

Hijack away, gentlemen! There is much that I need to learn/discuss, so all good with me!!

So...you know how last week I said



...well, as I am sure is the case with any project like this, it wasn't long before I found something else to add. I needed to cover the FT, for reasons of public safety, as well as keeping the fish in and randy cane toads out. It need to retain access to the tank for fish capture/pump maintenance etc, so I came up with this



25mm square galv steel mesh and double hinged frame. Think that oughtta get it done

Getting very itchy feet now...wantt to get some gravel in and fish etc!! Stoopid bills, stoopid life getting in the way of fun!

That cover looks great.. I need to do mine too, shade cloth and pegs just don't cut it



+1000

PS: Just noticed the Little Britain reference...

Hows the weather up your way, getting lots of rain like down here ?

Rain comes, rain goes...grass grows, I need to spend less time AP-ing and more time mowing, lol... It's not too bad, been getting a few overnight storms lately, with fairly clear days. Not the wettest wet I have ever seen.

But anyhoo. So I was looking back at the pumps in that link you posted on previous page, Veg. I was thinking I'd need something in the order of 8000lph, but am not sure now. I really don't have the money to buy and test four or five different rated pumps, so I want to get it right (or close) first go...I wonder, would 2500 be enough...or 6000?? Aside from the age old "trial and error" and "just plain luck" methods, are there any basic rules to pump size selection? I know about a siphon not starting/stopping being dependant on a pump being too small/too big, but that is something I will only learn after the fact... And also, I realise biofilm and algae in the pipework will come into play as well as the system matures...

Any hints??

E: Actually scratch that Q...I'll just go for the larger size (8000lph) and T some of the flow off, if needed. 8:40am, brain starting to work at last

Yep that sounds good to me. You already have 2 grow beds, I'm sure youll be expanding that in no time

I'm baaaack!!

Hey all. Sorry I dropped out for a while there. Been a bit busy with life etc, met a new girl, bought a new car, did some things, so the AP has been ticking along very slowly.

Updates: I ended up buying one of those cheap Bunnings pumps that I posted a page or so back. At $49, it was always just an experiment in what I thought would be the right size, without blowing heaps of cash. As it turns out, 8,000lph is waaay too much pressure, but I have since T'd much of that off and the flow is easy to control. Now I know where I'm at flow-wise, I will stump for a good pump in the near future. Also need to get a decent air pump...

I had a metre of scoria delivered and rigged up a simple sieve system to wash that as much as i could. Doing a few wheelbarrows a week, as time permitted, I got that all done in about five weeks.

I also ended up doing the electricals myself. Yes, I know, but my sparky mate didn't come through...I know he is busy with work and family and didn't want to hassle him too much. I figured if I get the red connected to the red, black to black and green to green, I should be sweet. And so far, the house has not exploded...touch wood!!

Still no fish, but I am drinking lot's of pee producing beer. I have also tipped about a litre of Charlie Carp into the fish tank (which makes 1000:1 ratio). I have a small tomato plant in place, as my first experimental shrubbery. I decided to leave it in it's punnet and soil, until it acclimates, is this a fair call? Advice needed there, as well as Charlie Carp dosages.

I will need to purchase a test kit soon as well, but otherwise just going to let the system run, 06:30-20:00hrs every day, so it can cycle away on it's own.

I have a few pics, but need to log in with my phone, since I cannot access any file share sites from work computer. Back in five...

!!! ALARM !!!

I added 40mL to 400L to get an ammonia reading of 2.0, which increased to 3.0 as the water evaporated down to 300L.

If you dose ammonia too high, this inhibits bacterial growth and effectively sterilises your system!

Do a water test!



Scott

Pics:

Scoria washing station


System up and going...at last!!




And a bit if a vid...in full 1080 glory


I also plan to install some wire mesh for tomatoes etc to climb on. You can see the batten fo this in place above GBs now...

Cheers for looking

Edit: Vid didn't work Nm, I will add that back in later.

OK, will do. I can drain a lot of water pretty quickly, as I incorporated a hose outlet at the end of water plumbing, for just such a purpose.

Cheers.

Looks fantastic Ghengis