what would be a cheap way to alternate the flow of a liquid between

>>938297
Are you talking drip line irrigation?

You set up 'zones'. Each zone is run for a particular length of time i.e. 1 hour. You can then use different emitters to control how much flow you get out the end. usually 1/2, 1, and 2 gallons per hour.

You're also limited by tubing size. for example my lines I buy, the 1/4" tube is limited to a 30' run and can supply 30 gallons per hour. So I can take a 1/4" line and put a couple T's in and get 15x2gph emitters.

The zones are controlled by distribution boxes that get instructions from a controller in the house, or an all-in-one distributor connected to the spigot outside.

>>938297
Anon, tell us more.

Manual switch to force flow to a different side? A unit that flpas back and forth so it goes to to both?

>>938297
there is gang valve manifolds sold for aquarium air hose use... some are brass and might corrode with water, but some cheaper ones are made of all-plastic

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put a pinch clamp on each line and open only the one you want to have flow.

>>938297
if you want to electronically automate this (or control it manually but with electrical switches) then you would use a solenoid valve.
Such as-- to find valves that can handle water and need 12 volts to operate, search Google for "12v water solenoid valve".

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You can literally get a plastic gate valve to put either side of the tee and they will cost pennies.

Why is that difficult? What's all this bullshit talk of pinch clamps and what not.

>>938942
Get real mate. Who's going to bother going to the trouble of automated solenoid valves for a bit of 4mm hose and irrigation. The valves and arduino would cost more than the irrigation system in its entirety and then some.