Water tank — pump needed?

I'm ordering a 10,000L water tank to go on a slab at the top of the (sloping) garden from where I hope it can water the vegies etc. Will I need a pump to run a sprinkler I wonder? It's about a one metre drop to the sprinkler. i guess the size of the gate valve/outlet on the tank is important. Any suggestions as to what size gate valve fitting I need to obtain maximum pressure would be appreciated.

Steel (Aquaplate from Bluescope) tanks are about 15% per cent cheaper than polyethylene tanks. Any arguments against them?

Hi JB/Rusty,
A 1 metre head will not develop enough pressure to run a sprinkler. Even with a full tank (say add 2 metres i.e. 3 m head) it is still unlikely to run a sprinkler.

So I would say that if you want to run anything other than drip irrigation or a slow running hose, you will need a pump.

The tank valve - I wouldn't be too worried about the size as it won't affect the pressure and will not cause any flow issues with just watering a garden.

Steel or poly - I prefer poly. But then again I have to rely on my tanks to supply water for the whole house (drinking, washing, etc). Your requirements are somewhat less critical, so maybe you can't justify the price difference.

Thanks Versnon. At this stage I'll probably try to get by with no pump, maybe setting up some kind of terraced flood irrigatiion system. My veggies are in raised and enclosed beds. Look to possibly fit a pump later if needed.

Are you sure about the outlet size making little difference? Even if it won't run a sprinkler, wouldn't water running out a 1" hose be much faster than through a standard garden hose?

The only difference will be the flow rate (i.e. the volume of water flowing) - the actual pressure (i.e. the force pushing the water) will be the same.

In your situation, where you are just watering the garden, the limiting factor will be the hose diameter - so as long as your valve has a bigger diameter than your hose, you will be fine.

If you were running water to the whole house or to multiple points simultaneously, then a bigger sized valve would be necessary (or at least more desirable).

The bottom line is, you wouldn't be able to tell the difference between the flow/pressure from a 3 inch valve or a 1 inch valve when watering your garden with a 12/13mm diameter hose.

Hope that makes sense :confused:

Hi,

If it were me, I would try without a pump first ,with a sprinkler, then maybe with some type of drip system, if no good you could always install a pump.

Cheers:)

I'd go for the drip system from the beginning. Delivered direct to where it's needed, less water lost to evaporation. Should be a major consideration anywhere water is in short supply. ;)

I would look at getting a sprinkler running as well, if only to wash the dust off once every month or so, but I wouldn't make it a major consideration. FWIW, 1m of head won't be enough to drive a sprinkler unaided, you will need a pump.

You need something like this.

As you are considering a tank from Bluescope, I suggest that you ask th<?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-comhttp://www.woodworkforums.ubeaut.com.au/<st1:PersonName>em</st1:PersonName> for advice regarding a pump (it must be a FAQ). It may be cheaper to install a pump (and all necessary fitting) at the time of installing the tank, rather than retro fitting the pump.

What Vernon said. It wont run a sprinkler
Do not sit a steel tank directly on concrete or the bottom will rust out.
Lay timber on the slab like the old tank stands to allow venterlation and stop the reaction between concrete and the sheeting.

David

that pump seems alright, but from a full tank it will give just over 5hrs watering... that might only be 20 days if you water for 15 minutes per day. 40 days if you water fifteen minutes on consecutive days.

rural supply stores often have well priced pumps, and would be able to advise on the pressure you'd need. you don't want to have to keep having the tank filled after all.

Thanks a lot for all the helpful responses.

Yes Vernon, what you said makes good sense. Sounds like my best bet is bigger outlet so I can use a larger diameter hose and get faster flow.

Buzzer, what you suggest is my plan.

Ekim, I have sprinkler available from a bore. Will use occassionally as you suggest. So why am I buying a tank? Cos I don't trust the bore pump, and I like the idea of having a spare tank hopefully full of water for emergencies.

Thanks a lot David for that suggestion. I was wondering about placing the tank directly on a slab. The Bluescope tanks are coated inside and out with something called Aquaplate, but I imagine it could easily be scratched (off) during installation. What do you mean by "Lay timber on the slab like the old tank stands"?

The top of the tankstand had 150 by 18 hardwood timber decking with 25mm spacings. Any rot proof decking should do even s/hand flooring with spacing to give an air space and allow drying, I doubt the aquaplate would give sufficient protection.

David