Sounds promising. Though household water is rated in PSI (something like 60 to 80 psi) rather than GPH. I have had to change our water pressure regulator twice (they only last 2-3 years here), and ours is pre-set at 65 PSI. Though I have herd that fountain pumps have enough pressure for those misters, (depending on how many misters, and pump). I have a 300-500 GPH (with a max 8.7 ft head height) fountain pump myself, but have not tried it with misters yet.

Now that you mention it, I should get some of the mister heads and do some testing on them myself. I have quite a few designs in mind, but really need to do some testing before I build them. I also have a water PSI gauge, I should test the pump to see what PSI it's putting out at different heights.

I can tell you it won't work with a 120 GPH pump!

Mike

Sorry to hear that,
I was wondering because know PSI and GPH are two completely separate measurements. Although I have herd that fountain pumps can support mister heads (depending on a lot of variables). Any ideas where your going to go from here? Different pump I assume, or different misters or design?

Actually psi and gph are not entirely different. they're related by the following equation:
(p1-p2)/ó+(z1-z2)+(V1-V2)^2/(2*g)=0
for short lengths of piping. where;
ó is the specific weight of the fluid (62.4 lbs / ft^3 for water)
p is the pressure
V is the velocity
z is the height the point of the subscript
and g is the acceleration of gravity (32.2 ft/sec^2)
the subscript
and 1 and 2 are subsctipts representing two different points.
if you know the max head of your pump you should know the pressure at that point is 0. also gph is known as volumetric flow, Q, which is = velocity x area. So if you know the max flow of the pump (taken at height zero) and the area of the outgoing pipe, you can easily get the velocity at height zero. let subscript one be at height 0, let subscript 2 be at the max head height. Solve for the pressure at height zero, then you have enough information that you can calculate the pressure and velocity at any height be letting said height set as subscript 2.
a lot easier to use the equation than to explain it. the trickiest part is making sure your units are consistent throughout.

Last I knew PSI is a measurement of pressure, and GPH is a measurement of volume, and you don't need to have both to have one. Specifically you can pounds per square inch (psi), without having any flow of a liquid (even when liquid is involved). Basically that's hydraulic pressure, psi being the amount of pressure being transferred to the liquid (weather it moves or not). Anyhow, that's why I said they are two different measurements.

It's nice to know that theirs an equation to figure out the PSI of a fountain pump, even if I don't really understand it. I guess I will need to re-read it a few times before I try it out. I did well at math in school (adding, subtracting, dividing, even fractions) until they started using letters instead of numbers, then I got lost and still just don't get it.

that's when a spreadsheet is your friend

grizzman
I have saved the formula to a text document, and plan to print it out to study. Although I'm also confused by what you mean about using a spreadsheet. I don't have any experience with using spreadsheets myself. I have a free program called
"Open Office" that's supposed to be the equivalent to Microsoft excel (I'm not paying the $150 for excel regardless). As far as I know it's capable of doing the same type of spreadsheets as excel, but I have no clue how spreadsheets work, or at least how it differs from a regular table. I mostly just use open office to create pdf. files, flyers etc.

P.S. I believe I read in another thread that you use a economical hydroponic nutrient solution "Southernag's soluble hydroponic solution" but I have not been able to find a source. Do you have a link? Also is it a complete hydroponic nutrient?

Its much quicker to attach a pressure gauge to check the psi than it is to mess about measuring flow, velocity etc :)
If the pump specifications include the maximum head in feet, simply divide it by 2.31 to find the psi. For example, a pump with a max head of 25ft "might" produce 10.8psi at zero flow.
To get some flow at 60psi you`d need a pump with a max head spec of 150ft (65psi at zero flow).

homehydro;
southernag.com is the supplier of the nutrient I use. it is not complete in that you also need to add calcium nitrate and magnesium sulphate (epsom salts). I bought my soluble hydroponics solution and my calcium nitrate from a local landscape supply company. just remember the cal-nit has to be greenhouse grade or water soluble. epsom salts come from walmart.
I use open office as well. that's why i said spreadsheet instead of excel. If you'll shoot me an email (see my profile) I will send you the equation in a spread sheet.
I believe it is easier to see a functioning one than to explain how to do it. Learn how to use it and it'll expand your horizons dramatically.

hex2006
I have a water pressure gauge, and just need threaded connector that threads into the it that has a barbed end to attach the vinyl tubing. Or similar connectors to be use it to test fountain pumps. I bought it to test our household water pressure because when the pressure gets to high (because of the regulator) it damages the RO system.

I intend to compare the information from grizzman's equations with what I get on the gauge. I'm interested in how you came up with the figure "2.31", I'm sure you didn't just pull it out of a hat. This too I probably will compare to the readings on the pressure gauge. I'm not looking for exact readings, but consistency compared to other readings. I mainly would like to have an idea how the pump will do before buying it. That's the main reason I'm interested in being able to figure that out by just taking the known values off the box, then getting a reliable "approximate" comparison is useful to me.

I mentioned this in my e-mail to grizzman:
It may be a bit far fetched, but I am even considering using a small electric pressure washer for the pump. It costs about $99, then I would need a external pressure regulator that I'm told runs about $80 (to reduce the output pressure). I would also need to build a good filter to make sure it wont clog. But with a bit of effort and fine tuning if I get it to work, for about $200-$250 I would have all the psi I needed, even to run a very large setup (not that I can afford it now).

The formula for psi of static pressure is the height in feet divided by approximately 2.31
The pressure washer pump would be a pretty noisy option, i`d check to see if it can handle the duty cycle before laying out the cash. With careful design, a system can maintain a constant minimum pressure for several weeks without any help from a pump.

I have herd the pressure washer run, and it was pretty quiet compared to what I thought it would be like. It is just a small electric one, the smallest I have found. Even so it would probably be annoying going on and off all the time. So I'm already planing to build a ventilated sound insulated box for it to dampen the sound.

I am not sure what you mean by "duty cycle." My only real concern is the maximum volume (GPH) of water it can put out in order to supply 20 to 40 mister heads, possibly more depending on the system I decide to use it for. I don't remember seeing a GPH rating on it. I imagine the mister heads have a GPH rating, and that I could use to multiply the GPH of the presser washer to calculate the maximum number of misters it could handle.

I don't know how a system can maintain a constant minimum pressure that can supply 20 to 40 misters without using a pump? But would like to know how that works?

40 heads would deliver a lot of mist, you must be planning something huge :) I can`t envisage ever using 40 heads but with 90 psi constant pressure my pump would need to run roughly once every 8 days. Upto a point,the number of misters and GPH is irrelevant, the trick is not to use the pump to supply them directly.

Well huge is a relative term, and what's huge to one may be normal to another. I don't have specific measurements, but I have a lot of designs I would like to try. But the one mentioned (20 to 40 misters) is roughly planed to be about 6-8 feet tall, 3-5 feet wide, and 6-8 feet long. It's a "A" frame design with plants on both sides. But again that's just one of my designs I want to experiment with. I do plan to have larger setups when I get things dialed in, even other system designs. I also have design I would like to try exactly the same as the one I had strawberry's growing in 2 summers ago, but converting it from a flood and drain to a aeroponics (soakeaponics)system.

I have no clue how you run a areponic system with the plant roots only getting watered once in 8 days, even if it's all day long. I intend to mist for about 1-2 minutes, every 15 20 minutes, and adjust as I feel necessary from there.

I am OK with a so called soakaponics system, I am not really concerned with droplet size at this point, I just want to keep the roots moist while ther hanging in air.

I mist for half a second every 7.5 minutes during the day and much less at night. The pump runs once every 3 weeks as i use fewer than 40 heads
With that amount of root space and 40 high pressure heads 2 second mistings would be a reasonable starting point. Soakaponics will work fine provided you use enough heads to cover the root space evenly. High pressure mist tends to travel further with better distribution per head so you`d need less heads for a given root volume.
If you overdo the misting with a high pressure setup it will deliver exactly the same results as a soakaponic setup. Unfortunately it doesn`t work the other way around, it would make it a lot cheaper.

I have no definite plan yet, just considering ideas at this point (for a number of setups). Another option I want to look into is the pumps used for patio misting systems, but from what I've seen so far, there not cheep (good ones anyway).

Sounds like your using a pressurized tank (you say at 90 psi). And probably use a solenoid to open and close the line to the mister heads. Although the timer isn't an ordinary timer with on off cycle intervals of less than one second. I'm guessing the solenoid timing is probably computer controlled. That's not an option for me at this point.

Between the pressurized tank, pump that can deliver the 90 psi, solenoid, and specialized timer, that would all get quite pricey for me.

Nothing as sophisticated as computer controlled, just a basic homebrew cycle timer which controls the solenoid. Both the timer and solenoid run on 12v dc, so there are no power outage issues.

Well I am not really interested in building my own timer at this point (I don't want to leave reliability to chance), although I used to know someone who did/does (even DC, and with a photocell). Though he was waiting on getting the UV listing certified at the time (about 6 months ago, last I herd). I was not really considering a timer with on/off cycles less than 1 minute. But maybe I will ask at radio shack to see what's involved in building one (including cost for parts). Then if it seems reasonable, I may consider building my own. But it would need to pass my reliability testing before I trusted it, and I would defiantly want the settings adjustable. Including day night settings, as well as different settings for the hot part of the day.

P.S. When you said "Homebrew" I was expecting it to be used in making your own beer, even though i was not sure what you would need a timer for in making beer. I made my own beer many years back and never used any timers. But anyway that through me off at first.

The problem i had with commecial timers,apart from cost was they either didn`t go low enough or it was almost impossible to hit the right setting with a rotary control.
I have switch selectable so repeatabilty is guaranteed everytime, it has 0.25 second steps for mist control and 30 second steps for the pause interval.
As for reliability, i built several timers so i`d have a few backups, a year down the line and i haven`t needed them yet.

homehydro,

Depends on what you mean by cheap for patio misters. Wally's World sells 30 feet of misting line (16 misters) plus ten feet of supply cable for $25.

Mike

wordwiz
Yes, misters and the tubing are not a problem. Some misting lines don't even use a pump, they just tap into the household water pressure through the water faucet. But when there are more than a few mister heads, or a finer mist is needed/wanted, they require a pump to boost the PSI.

I have not really gotten around to looking into all the options with patio misters yet, but I have seen pumps for the misting systems at Home Depot etc., and if I remember correctly the ones they had were somewhere between $125 and $200. But there are two types of patio misting systems (high pressure, and low pressure). The high pressure pumps range in price but can be over $1000. The low pressure systems run solely off of household water pressure (I believe), but again are limited in the amount of misters because of the household water pressure.

I can't use household water pressure because I don't have nutrient solution coming out of our water faucet. So I would need a pump that can provide enough PSI. The more misters the higher the PSI would need to be. If I remember correctly hex2006 posted a link to similar pumps that were $300-$400, I would consider that pricey. hex2006's setup sounds like the way to go for the most economical design, but all things considered out of my price range for now.

I would like to keep the price of the pump under $100, but have not found anything that would work for that many misters for that price yet. High volume fountain/pond pumps might work provided they can provide enough pressure, and that I am unsure of at this point. Even if so the high volume fountain/pond pumps that I have seen at Lowe's and Home Depot run from about $80 to $250. I plan to first test the fountain pump I have (it was $45) to see how many misters it can handle, and go from there before making any decisions.

Also I don't like to by pumps that just barley do the job. If I want to expand on the system, or ever need to add a few more misters to get better coverage, I don't want have to buy another pump. I may even decide to use it for another system all together. I like overkill, I would rather need to split the line into 2 or 3 lines and divert it back to the reservoir to reduce the pressure, than need to buy another pump because it's to week.

homehydro,

How many misters would you be looking at? I need to cover only about 16' so the Patio Mister 30 is perfect for me. ILike you, I can't add nuits to the system is I use the faucet, but this will be simply to grow seedlings in flats. Once a week, I can get out my hand sprayer and water with it!

Some options that you may or may not have considered:

Adding an in-line fert distribution system. It's generally about as simple as one of those Miracle Grow nozzles one adds to a garden hose and you dial the percentage of nuits you want.

A shallow well pump. These run about $200 and more new but last for years and years. Right after we were married I moved into my wife's house. It had a deep well pump where water was pumped into a holding tank. That kept the pump from kicking on every time someone flushed the toilet or washed their hands. They provided more than enough pressure.

A sump pump. Less expensive but I'm not sure how much pressure they deliver.

A PTO pump. You could run it off a motor such as a lawn mower with a little adaption.

I will need to disassemble my aeroponics system in a couple of days to move it (got two, 600-watt MH lights today!) and I'll see how the patio mister I have works or doesn't work with a 580 GPH pump.

Mike

you can use the tap supply if you have decent pressure and reasonable water quality. It has it own issues like on-the-fly ph and temperature adjustment. You`d also need to run to waste but other than that is very do able.
I must have explored almost every possibility over the years :)
http://www.dosmatic.com/

wordwiz
I don't remember if I mentioned it here, but I'm considering many different (areoponic/soakaponics) setups. But the specific one I guess I'm specifically speaking of in this thread is planed to have between 20-40 misters. But I'm more interested in adaptability, because I have a lot of things I would like to try. Even resurrecting the first system I ever built, converting it from a flood and drain (ebb & flow) system to a aeroponics system (sorry Soakeponics). I still like that setup, but it took about 50 gallons to flood at first, with a few modifications I got down to 32 without running the pump dry. But the same exact setup as a soakaponics system I can run it easily on 10 gallons of nutrient solution (even less).

Or I can triple the size of the system for the same amount of nutrient solution, from 32 plants to almost 96. But in that situation each growing chamber holds 8 plants and will probably take 8 to 12 misters (soakaponics misters). That would be a minimum of 32 misters for 4 growing chambers. Triple that and you have 96 (or basically one per plant).

Thanks for the ideas on the different types of pumps, I cant say I have really looked into any of those options. I am familiar with PTO pumps in a way. I used to drive a tow truck and that is what drove our hydraulic systems, but I never worked on one. I don't want to connect it to a gas engine, but see no reason I can't use a electric motor. That would be easy to connect the timer to and is a lot quieter (I just need belt to connect them). Also using it in a different way and building on hex's design, it is possible to use it to pressurize the tank. But I have not looked into how much they cost.

As for sump pumps, they are on the list of things to consider but have not really looked into them yet, and I'm not really sure how they differ from a well pumps. But that has given me some new keywords for searching, and I assume that well pumps would have a descent head height (resulting in PSI). Long run depends on price (I don't care what it's called). I also have herd of someone modifying a (DC) car window washer motor to pump nutrient solution through misters (not sure where though).

hex2006
Thanks for the link. I don't see how I can consider run to waste options like that right now. First the injectors look expensive (and need to be controlled by something), second we have very bad water quality. Also summer time temps are high. I need to run the water for about 5-10 minutes before I can even get in the shower (tell it cools off a bit). That's with running the cold water only, and the hot water heater power/breaker shut off all summer.

With a high pressure misting system, a run to waste option is considerable. But with the the limitations I'm working with (mostly money) just cant see it as a feasible option.

Hex2006;
you don't by chance have schematics and/or parts lists for those timers do you?

Hi Grizzman
I do..somewhere, i`ll see if i can dig it out. Bear in mind i designed it for a specific task so i`m not sure how well it`ll fit with your application. What sort of timing range do you need?

homehydro,

One other option, a really cheap one that I am using and don't need a huge pump for - drilling tiny holes in PVC pipe. I bout a 3/64" drill bit, one could go smaller. Measure where the plants will be and drill a hole there, straight down. Or make it fancy and drill it at an angle. It puts out enough of a stream of water to keep the roots wet and I don't have to worry about misters clogging. I suppose if one wants a finer stream, they could buy some cheap window screening and wrap it around the pipe a couple two or three times. Very low-tech, but highly effective. It can also be set up with a timer so the water flows for 15 minutes and is off for 15-30 minutes.

TBO, I have as much fun trying different things and seeing how they turn out as anything else.

Mike

Hey Hex,
sorry for the late reply. I'm probably interested in something along the lines of 5 seconds on, and 30 off.
Although if you just find your initial diagram, I would love to see that.
Thanks.

My experiment with "Soakaponics" took a set back. My 550 GPH was/is not strong enough to deliver the water I need. I've ordered a 1200 GPH pump which should do the job.

It needs to deliver enough water through two, 12' 1/2" pipes with 3/64 holes drilled in them to cover about 36 square feet.

Mike