Uneven water output with drippers

[Muarco]

Hey there, I looked a bit around but couldn't find a thread regarding this. I'm running a 475gph submergible pump with 32 drippers. 5 are like the ones shown in the picture and the remaining 2 are single. I'm testing the system and noticed I'm getting uneven water delivery. I measured with cups different drippers and noticed a big difference of around 20ml in 1 minute. The drippers are rated for 33ml x minute from a single stake. Irrigation line is about 10ft long and goes up vertical for 6ft before going back down into the tent. Also I noticed some water leaking from the emitters near the hole into the tubing. I used a poking tool and had to push quite a bit to get the emitters in. Any insight is appreciated guys.

 

[stiff]

I think its mainly about length of hose. Make sure they're 'exactly' same length for the same output. Not sure about the pressure issue when u push it upwards,but that might explain why u get less then u should...still an easy one to fix,just run it longer
I hope that helps,stiff

 

[Muarco]

I think its mainly about length of hose. Make sure they're 'exactly' same length for the same output. Not sure about the pressure issue when u push it upwards,but that might explain why u get less then u should...still an easy one to fix,just run it longer
I hope that helps,stiff

You're referring to the spaghetti hose or the main 0.63 inch tubing?

My main issue is that some plants will end up getting more water than others.

Here is how I set it up.

 

[Bush Dr]

It’s called hydraulic friction losses … you can even it out by using 2 drippers per pot arranged 1&32, 2&31, ec

….. why do I fucking bother ….

 

[unnamedmike]

My system is way smaller that yours, and im using 20mm tubing, for your setup i recommed you 3/4". What pump are you using ? you need a pump with a good work pressure, like the pumps for camping, trucks, etc.
My system is working since yesterday: 30 drippers, same amount of nutrient solution in every drippper.

 

[Muarco]

My system is way smaller that yours, and im using 20mm tubing, for your setup i recommed you 3/4". What pump are you using ? you need a pump with a good work pressure, like the pumps for camping, trucks, etc.
My system is working since yesterday: 30 drippers, same amount of nutrient solution in every drippper.

View attachment 18130847 View attachment 18130848

Do you have any leaking nearby the emitters? I think could also be that causing the loss in pressure. To optimise I could avoid running the tubing on the ceiling and gain more pressure by staying horizontal. I'm using a 1800l/h pump. Trying to figure out if the problem is with the pressure of with the emitters/tubing.

 

[unnamedmike]

Do you have any leaking nearby the emitters? I think could also be that causing the loss in pressure. To optimise I could avoid running the tubing on the ceiling and gain more pressure by staying horizontal. I'm using a 1800l/h pump. Trying to figure out if the problem is with the pressure of with the emitters/tubing.

I think you need a pressure pump, a 5 stages or similar, check Seaflo for RV, for example, not sure if i can share the link, but is easy to search. you need more pressure, not more flow speed. My system dont leak. Do you have a pic of your pump ?

 

[Muarco]

I think you need a pressure pump, a 5 stages or similar, check Seaflo for RV, for example, not sure if i can share the link, but is easy to search. you need more pressure, not more flow speed. My system dont leak. Do you have a pic of your pump ?

Sure, here is a picture of the pump. The tubing is around 6m long for the first tent and 8m long for the second tent.

 

[stiff]

I love both of your systems.
Yeah,try to get rid of the leaks. Then maybe stronger pump,but think of maybe having two pumps for the four tables. A while ago I read on cocoforcannabis they recommend two in two rows of tables to avoid pressure troubles

 

[troutman]

Maybe, placing a few control valves would help.

 

[Roadblock]

Sure, here is a picture of the pump. The tubing is around 6m long for the first tent and 8m long for the second tent.

That pump is not big enough, if you take the rated max head number of that pump and throw it into this calculator you will get you psi , you need at least 15psi and a octa bubbler to regulate your flow rates to all drip lines.

Convert meter of head to PSI - Conversion of Measurement Units

Do a quick conversion: 1 meters of head = 1.4219702063247 pounds/square inch using the online calculator for metric conversions.

www.convertunits.com

Im just setting mine up now and bought a transfer pump that gives me 32psi, Im limited to wattage so got a small one that runs on 370 watts for 1350 GPH flow rate, Im only running 8 drippers on it but I want an accurate constant flow and you gotta have decent water pressure to do that.

I got this one

Water Transfer Pump - Garden Irrigation

Buy CPM130 - a quality centrifugal water transfer pump, perfect for irrigation in a smaller garden or around the farm pumping up to 90 L/min with Free Shipping.

waterpumpsnow.com.au

 

[CrushnYuba]

Hey. I'm curious where u got those drippers? I have seen those emitters everywhere. China is cranking them out, but the multi outlet manifold on top is different then what I usually see. I like that it goes up instead of to the side.
Yea, like the other guy said, use 2 per pot. If you look at the netafim or jain installation manuals they usually show 2 stakes per pot and they are from 2 different emitters. That just happens with multi outlet emitters. But some more then others. There is variation in manufacturing. They can it CV. It's coefficient of variation. Happens in all emitter manufacturing. The good brands made in Fresno California or Israel are on top of it. GOOD factories in China will try to limit it also. But there are hundreds of Chinese factories making those same emitters and arrow stakes (although I haven't seen that manifold). The molds were probably old on the stakes. The labyrinth is probably slightly different. Have you tried switching the stakes into different pieces of tube? If the flow difference follows the stake that's it.
More pressure may fix it though. That pump is for a fish tank, not plants. Sometimes a little more pressure can overcome high cv.

As far as the leak, you probably used the wrong size punch tool for the emitter or a crappy one. What size punch did u use? Pull it out, stick a goof plug in the hole. Wrap it in SILICON tape if the old hole still leaks. Punch it again. The other possibility is it's just shit PE pipe that doesn't have enough stretch. Tell me what brand pipe and show me a picture of your punch tool.

Those free or 1$ tiny plastic pokers will stretch your hole out and it won't seal right. You need one with a spring that cuts into it with a coned metal point. If it's hard to punch, you are stretching the pipe. There are some decent ones for 5$ that will make a clean tight hole

I install irrigation pumps for a living.

 

[f-e]

The pump is useless.
The 6 stakes are running from what I presume is a pressure compensating valve. These are standard items. In operation, they demand a certain amount of pressure in that black manifold, or they won't regulate the flow properly. Typically speaking, the system pressure should be 1 bar. That's also 10 meters of head, or 15psi. If you don't meet this pressure demand, the PC parts can't work.

If we could look at the output of a single PC emitter, with variable pump, the picture might be clearer. As the pump comes on, the emitter will pass fluid. As the pump was turned up, more fluid would pass. At a certain point, usually 15psi, the flow rate reaches what the emitter should allow. Then, turning the pump up further, nothing happens. The emitters output is capped at the rated 12lph?

If you use a pump that can get that black pipework over 15psi (if they are 15psi rated) then all the PC parts will flow the same 12L to the 6 stakes. 33cc each.

This is how pressure compensating systems all drop the same. You must have enough pressure to reach there maximum output. It's only then, that they all flow the same. If your pump can't give them the pressure to flow at the rated delivery, then the compensation is lost, and the water piddles out the easiest route.

The system of barbed connections pushed into the wall of the pipe, relies on system pressure to seal them. Proper pressure will close that leaky gap. 15psi is half a car tyre. It pushes quite a bit.


Not all emitters are equal. Some are for 0.5 bar systems. That's a pressure a few pumps can reach. Typically a system is 1 bar. This is quite hard to meet, but there are pumps can do it. The octobubblers spoke of need about 1.7 bar, and are outstandingly difficult to cater for.


Notice here, that we have been quite specific about what the pump must do, but not once have we spoke about gallons per hour or any such equivalent. We are concerned with static pressure, not delivery volume.
You need just 64 liters per hour from your pump. 32x2L. What we don't know, is the pressure your PC parts expect. So must presume a bar (10 meters of head)

3 phase pumps, the latest thing.

The latest and greatest in pumps. The 3 phase DC pump. I'm not talking industrial here. It's the new whisper stuff that deserves the name. A few aquarium shops are getting these in as high end stuff, like $100 and it's only really one supplier on Ali that has them. Minco...

www.icmag.com

^^ lots of cheap, decent, and fairly quiet pumps there.

 

[f-e]

@unnamedmike
The equal pressure manifold is a nice touch. Even if you didn't reach working pressure, I bet the delivery would be nice an even. This can save a crop from some unexpected failures. Like a $10 bag falling in the tank and partially blocking a pipe or something.

I'm just looking at the mains power to the PSU. It seems you have no cable relief, and it's hanging by the earth wire. Perhaps I can't see a tie to the pumps foot ? It's good practice to leave the earth longer at termination points, so if something snaps, it's not the safety connection first. These PSU's have a lot of radio and line noise reduction circuitry that needs an earth. An unseen risk, of the cable guy knocking.

 

[CrushnYuba]

I think i was wrong. I was looking for those 6 way emitter manifolds because I like that they go straight up instead of a 90 like all the others. I was gonna order some. I thought it was high cv on the arrow stakes labyrinth. But it doesn't actually look like there is any labyrinth at all. There is nothing at all to regulate flow between the different stakes like there is 90% of the time with multi outlet drippers. I think if you swapped them out for proper arrow stakes, you would notice a big difference or you can change the configuration to 2 stakes per pot (more material cost). Usually I see both, 2 regulated stakes per pot from different emitters. Look at the netafim and jain manuals to see how they do it. You can get a regulated arrow stake for .10 cents a piece.

 

[f-e]

I run the labyrinth 2L arrows. With the equal pressure manifold and 1 bar pump, I see 33cc at every one.
I have not seen them used after a PC part. Any restriction after a PC part, is pressure lost across it. If I used a 2L labyrinth arrows, with a 2L PC valve rated at 1 bar, I would actually need 1.5 bar to make it work. As the arrow would be backing up pressure, reducing what was across the PC valve.

Using a PC part, and then splitting up the outlet, means them outlets need attention. They must be using equal pipe lengths and be at equal height.

 

[CrushnYuba]

The big companies like netafim and jain are making multi outlet drip assemblies. The tube is already cut evenly and they are already assembled to save time installing. Those usualy have arrow stakes. It's just something to give a little back pressure to even out flow, not very restrictive. It seems like these are precut assemblies as well so I doubt it's an issue of length. And an inch difference in the pot shouldn't make a difference. There's a reason to use arrows and put 2 in a pot from different emitters

 

[G.O. Joe]

That should be plenty of pump but that 6' vertical part is not helping, even if it's rated for over 6' - I'd change that first. I use a Tetra SP140 for 8 drip stakes (Hydrofarm, 1/4" OD Rainbird tube in 1/2" ID schedule 40 PVC manifold with PTFE tape) and it's turned down to the minimum, probably less than 100 GPH, and that's just low enough for the stakes not to spray all over.

 

[Muarco]

Hey. I'm curious where u got those drippers? I have seen those emitters everywhere. China is cranking them out, but the multi outlet manifold on top is different then what I usually see. I like that it goes up instead of to the side.
Yea, like the other guy said, use 2 per pot. If you look at the netafim or jain installation manuals they usually show 2 stakes per pot and they are from 2 different emitters. That just happens with multi outlet emitters. But some more then others. There is variation in manufacturing. They can it CV. It's coefficient of variation. Happens in all emitter manufacturing. The good brands made in Fresno California or Israel are on top of it. GOOD factories in China will try to limit it also. But there are hundreds of Chinese factories making those same emitters and arrow stakes (although I haven't seen that manifold). The molds were probably old on the stakes. The labyrinth is probably slightly different. Have you tried switching the stakes into different pieces of tube? If the flow difference follows the stake that's it.
More pressure may fix it though. That pump is for a fish tank, not plants. Sometimes a little more pressure can overcome high cv.

As far as the leak, you probably used the wrong size punch tool for the emitter or a crappy one. What size punch did u use? Pull it out, stick a goof plug in the hole. Wrap it in SILICON tape if the old hole still leaks. Punch it again. The other possibility is it's just shit PE pipe that doesn't have enough stretch. Tell me what brand pipe and show me a picture of your punch tool.

Those free or 1$ tiny plastic pokers will stretch your hole out and it won't seal right. You need one with a spring that cuts into it with a coned metal point. If it's hard to punch, you are stretching the pipe. There are some decent ones for 5$ that will make a clean tight hole

I install irrigation pumps for a living.

Great insight man! I swapped the old pump for a new more powerful one and got rid of the vertical climb.

Tubing is now running on the floor and I gained quite some pressure. I checked the drippers again and I seem to have a more even water distribution. Regarding the leak though, I'm still not making progress. I tried 2 different punching tools and 2 different type of tubing but I'm still getting leaks from a couple of holes.
This is the tool and the tubes I'm using. The diameter of the tool is 4mm. One tube is soft while the other is harder plastic.

Regarding the drippers, this is the model I'm using in picture. Octopussy

 

[Muarco]

The pump is useless.
The 6 stakes are running from what I presume is a pressure compensating valve. These are standard items. In operation, they demand a certain amount of pressure in that black manifold, or they won't regulate the flow properly. Typically speaking, the system pressure should be 1 bar. That's also 10 meters of head, or 15psi. If you don't meet this pressure demand, the PC parts can't work.

If we could look at the output of a single PC emitter, with variable pump, the picture might be clearer. As the pump comes on, the emitter will pass fluid. As the pump was turned up, more fluid would pass. At a certain point, usually 15psi, the flow rate reaches what the emitter should allow. Then, turning the pump up further, nothing happens. The emitters output is capped at the rated 12lph?

If you use a pump that can get that black pipework over 15psi (if they are 15psi rated) then all the PC parts will flow the same 12L to the 6 stakes. 33cc each.

This is how pressure compensating systems all drop the same. You must have enough pressure to reach there maximum output. It's only then, that they all flow the same. If your pump can't give them the pressure to flow at the rated delivery, then the compensation is lost, and the water piddles out the easiest route.

The system of barbed connections pushed into the wall of the pipe, relies on system pressure to seal them. Proper pressure will close that leaky gap. 15psi is half a car tyre. It pushes quite a bit.


Not all emitters are equal. Some are for 0.5 bar systems. That's a pressure a few pumps can reach. Typically a system is 1 bar. This is quite hard to meet, but there are pumps can do it. The octobubblers spoke of need about 1.7 bar, and are outstandingly difficult to cater for.


Notice here, that we have been quite specific about what the pump must do, but not once have we spoke about gallons per hour or any such equivalent. We are concerned with static pressure, not delivery volume.
You need just 64 liters per hour from your pump. 32x2L. What we don't know, is the pressure your PC parts expect. So must presume a bar (10 meters of head)

3 phase pumps, the latest thing.

The latest and greatest in pumps. The 3 phase DC pump. I'm not talking industrial here. It's the new whisper stuff that deserves the name. A few aquarium shops are getting these in as high end stuff, like $100 and it's only really one supplier on Ali that has them. Minco...

www.icmag.com

^^ lots of cheap, decent, and fairly quiet pumps there.

Thank you so much for taking the time to explain this in detail. I'm not sure if my emitters are equipped with such valve but I'll add a link to a website that carries them.

Drippers
New 7000l/h high pressure pump

So with the higher power pump I seem to have fixed the issues with uneven pressure. I really appreciated all insights. Once again this forum proves how strong and united the cannabis community is.

I still had to fiddle with the leakages near the emitters. My poking tool has a diameter of 4mm. I did notice that when I apply pressure to the tube it bends near the point of pressure before it goes through the plastic. I'm using a standard 16mm irrigation tube. The same you would probably find at a garden center.