you need to be careful. but double check ATV boom sprayers, they normally have a 12V pump. that you can hook up to your battery on your truck.
i say careful, due to the alternator may not have enough juice to keep the battery charged. granted it should, but if ya run say A/C, fans on high, head lights on high beam, radio full blast. you use up electricity and it has to come from some place. but you should be able to get by just fine.
if ya ran cables off of battery, you could put an inline fuse and a switch inside the cab. to be able to turn on/off pump.
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goto
Koiphen.com and do a search for "spray bars" you will find spray bars being used for "trickle towers" and micro screens placed in settling chambers.
WorldWide Koi Club - Home -> pond building -> filters or diy. (been some time) there are man DIY builds of spray bars. listed there.
spary bars. are made out of pipe most of the time PVC pipe, with caps on the ends. and then smallest drill bit possible used, for some things. while larger holes used for other things.
example. say you placed a outlet on lowest portion you can on the tank. ((most likely using a "uniseal" vs a bulkhead fitting, so you can get it closer to bottom of tank if placing it on the side of it)) and then a pipe through the uniseal, then to a Tee with some pipes out each end for some booms. you could do this with little bit bigger holes. and just run the truck up and down and let the water gravity flow out of the holes.
if you do above, your best bet is making a single line of inital "holes" and see how it does. if not enough water comes out, ((more so when tank is getting near empty)) drill a couple more holes. this will most likely be trial and error and a couple pieces of pipes hacked up and tossed away. till ya find something you like.
you will most likely want say a 3" or 4" outlet on tank, then 2" to 3" booms if you do the gravity flow of water thing.
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if you are wanting to use a 12v pump. and have more of a spray pattern. vs trickling of water, like above would give you. i would suggest making 2 rows of smallest size drill bit you can find. and do the trial and error of above. of drilling some holes initially, then as needed drill some more holes.
for this setup. 1.5" to 2" booms should work. you could use something smaller. but the problem comes down to getting even flow of water across the booms. and you may find it that the center of the booms has less holes while further towards ends have more holes.
if you want to pay the cash, you can get the little "spray nozzles" that are self taping, (drill a hole in the pvc pipe, and twist in (will be tight)) to get a misting effect. ((actually you should be able to pick up "misters" and adjust them for patterns and/or use a drill bit to make them send out more water.))
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others would most likely state better. but i would most likely avoid fine misting. due to loss of water to the air. vs going to the ground.
thinking about it, you might be able to hit a local scrap yard. and take the spray bars out of some "trickle towers" errr forget the names the boxes that set up on your roofs and water runs down through fins to cool your house vs A/C units.
