What's new
  • Please note members who been with us for more than 10 years have been upgraded to "Veteran" status and will receive exclusive benefits. If you wish to find out more about this or support IcMag and get same benefits, check this thread here.
  • Important notice: ICMag's T.O.U. has been updated. Please review it here. For your convenience, it is also available in the main forum menu, under 'Quick Links"!

Grow Tray / Drip Manifold -Water Pump Size

alpo

Active member
What size water pump is needed for a drip to waste manifold using max 36 0.5gph drippers - 1" feed tubing approximately 15 feet plus 1" 4 feet manifold. Using Rockwool

Will a 400gph submersible pump on a timer work?

Thank You
 

Fixer

Active member
I tried a 600 gph with 24 Netafim 2 gph emitters but no luck. Had to bump up to a Mondi 1585 to get them to flow. Good luck!
 

f-e

Well-known member
Mentor
Veteran
36x0.5 is 18G. It's a fallacy shared by most that having a pump that can do more than this is needed. Any pump can shift 18G an hour. The question of if it can shift 18G through a little hole isn't answered by capacity, it's answered by the pumps lift.

Fans are the same. A desk fan shifts about as much air as a tube fan. The tube fan costs 5 times more though. However 5 desk fans can't do the job of one tube fan when the resistance of a filter needs to be overcome.

Moving from a 100g pump to a 500g pump isn't going to achieve anything if both have the same 5 meter head/lift because that is as hard as they can push. The Gallon rating has literally no meaning. You only need 18.

The 0.5g dripper is rated 0.5g when supplied 1 bar/10 meters/15psi. That is the pump rating that matters.

The Mondi 1585 has 9 meters so doesn't have the pressure to operate the drippers at capacity.

The 1" pipe is a problem. It holds almost a Gallon of water. The first Gallon you fertigate with has been sat in a pipe for.. dunno how long. It's possibly going to be hot and lack aeration. It's not been stirred for ages and it's a large area for slime to grow. At 18gph you could probably use 1/4" push fit. Though most fittings you find will be 1/2" like garden hose. Simple barbed connectors.

If you search my posts for the word Whale you will likely find a fist sized pump at about 50w that makes that Bar for $30.

I'm still lost for why our industry has yet to make us a decent pump. Some inline condense pumps are about right.
 

YoungBreeder

New member
36x0.5 is 18G. It's a fallacy shared by most that having a pump that can do more than this is needed. Any pump can shift 18G an hour. The question of if it can shift 18G through a little hole isn't answered by capacity, it's answered by the pumps lift.

Fans are the same. A desk fan shifts about as much air as a tube fan. The tube fan costs 5 times more though. However 5 desk fans can't do the job of one tube fan when the resistance of a filter needs to be overcome.

Moving from a 100g pump to a 500g pump isn't going to achieve anything if both have the same 5 meter head/lift because that is as hard as they can push. The Gallon rating has literally no meaning. You only need 18.

The 0.5g dripper is rated 0.5g when supplied 1 bar/10 meters/15psi. That is the pump rating that matters.

The Mondi 1585 has 9 meters so doesn't have the pressure to operate the drippers at capacity.

The 1" pipe is a problem. It holds almost a Gallon of water. The first Gallon you fertigate with has been sat in a pipe for.. dunno how long. It's possibly going to be hot and lack aeration. It's not been stirred for ages and it's a large area for slime to grow. At 18gph you could probably use 1/4" push fit. Though most fittings you find will be 1/2" like garden hose. Simple barbed connectors.

If you search my posts for the word Whale you will likely find a fist sized pump at about 50w that makes that Bar for $30.

I'm still lost for why our industry has yet to make us a decent pump. Some inline condense pumps are about right.



i was thinking along the same lines . 1 inch tubing is the real issue with the water flow not the size of the pump . especially using a manifold and micro dripers at .5GPH 1 inch isn't small enough for the pressure to build up and the water to actually flow. and that pressure, is what could possible help overcome the lift no?. if the lift is another issue.

another question for OP. including the 15 feet of line.
how high is the tables over the res?
&
is that same 1inch running directly from the pump?
 

alpo

Active member
i was thinking along the same lines . 1 inch tubing is the real issue with the water flow not the size of the pump . especially using a manifold and micro dripers at .5GPH 1 inch isn't small enough for the pressure to build up and the water to actually flow. and that pressure, is what could possible help overcome the lift no?. if the lift is another issue.

another question for OP. including the 15 feet of line.
how high is the tables over the res?
&
is that same 1inch running directly from the pump?

It will be 1" from the pump to the grow space (12 feet), then maybe 3' max-height to the tables and the manifold. I see u/Pico manifold thread uses 3/4" for the manifold - is a quarter-inch a deal-breaker? I can use a reducer after the 1" where the line goes up to the table and manifold. would 1/2" or 3/4" PVC be better for the manifold?

I will probably use a little bit bigger pump too

Also, I am going to build the stands for my tables - Do I need to make the drain side at a slope?

Thanks
 

YoungBreeder

New member
It will be 1" from the pump to the grow space (12 feet), then maybe 3' max-height to the tables and the manifold. I see u/Pico manifold thread uses 3/4" for the manifold - is a quarter-inch a deal-breaker? I can use a reducer after the 1" where the line goes up to the table and manifold. would 1/2" or 3/4" PVC be better for the manifold?

I will probably use a little bit bigger pump too

Also, I am going to build the stands for my tables - Do I need to make the drain side at a slope?

Thanks


ok yea, that's way too far to use 1 inch and the pump size you said. how big is the res? is that inline or sitting in the res?

I can't tell you what to do or what's "right". i can only tell you my opinion, and what I do. I've never done anything bigger than 3/4 going directly from the pump. and currently, I'm running 1/2PVC from mine then adapts to 3/4 then to 1inch when it hits the table if I put all length together maybe 10 feet of pvc and my pump isn't more than 300gph, never had a problem with the flow so far and im running 16 sites. so id say yes changing the line running to the table is definitely best for your situation and with the distance being what it is, id run 1/2 inch just to be safe. then use a 3/4 adapter when you get to the table and keep that line. for connecting to all your manifolds since theyre threaded 3/4 anyway.
or if you upping the pump anyway just use all 3/4. from the pump to end.
 

YoungBreeder

New member
and about the slope of the table. i put a small one on mine but It wsnt a priority, I'm using a botanicare tray , so its already slopped. but if you are building the tray as well out of wood. YES make sure to account for the slope.
 

alpo

Active member
ok yea, that's way too far to use 1 inch and the pump size you said. how big is the res? is that inline or sitting in the res?

I can't tell you what to do or what's "right". i can only tell you my opinion, and what I do. I've never done anything bigger than 3/4 going directly from the pump. and currently, I'm running 1/2PVC from mine then adapts to 3/4 then to 1inch when it hits the table if I put all length together maybe 10 feet of pvc and my pump isn't more than 300gph, never had a problem with the flow so far and im running 16 sites. so id say yes changing the line running to the table is definitely best for your situation and with the distance being what it is, id run 1/2 inch just to be safe. then use a 3/4 adapter when you get to the table and keep that line. for connecting to all your manifolds since theyre threaded 3/4 anyway.
or if you upping the pump anyway just use all 3/4. from the pump to end.

oh ok, I thought you had facts the 1" wouldn't work.
 

f-e

Well-known member
Mentor
Veteran
The surface area of the pipework all needs pushing upon by the pump. The more pipework in length or width you have, the more inner surface needs pressing on. All of which takes power.

The only issue we have with big hoses is all the water often left within them. With a raised manifold you can have it run back to the tank.

The Whale GP1652 can supply more than 18gph (240gph) and of actual importance, it can produce 1.4 bar. That's 14 meters of head or ~21psi so it truly whales most things. It's 50w and fits through the neck of a 5L feed bottle. Placed in the center of a bucket, at least 6" from any side, you can't hear it. Long ago I calculated a 120 dripper limit and have regularly done 60. That's with losses for filters and double check valves.

On the negative side, they don't want to ever run dry. In a new installation, you must let the air out of the pipework above it, to allow water to rise up into it before use. For me, that's at the filter, as I always put my filter over the tank. It's a break in the pipework, so may leak.
The other issue, it's 12v (or 24) and while a psu is cheap, switching them with a timer is like switching a 600. 95% of walmart timers will fail.

For the electrically minded that might do this, I use a 5 amp brick. In the 12v wire to the pump I add a 12v relay. It's a delay. The brick must reach 12v to flick the relay, so the power can continue through the relay to the pump. It's a tiny power delay, but some psu's can refuse to start if they don't make that 12v in a flash and a pumps load can take some inrush. Delaying the time it takes to rise to 12v and thus putting the bricks protection light on. The time it takes a relay to move is enough to stabilise the rare brick that needs it.

An easier option might be to plug the brick in permanently and use a 12v timer. That is what I do as most of my kit is 12v. I think I have 6 12v timers that can be set to the nearest second not minute. A minute is a long time when a dripper is running about 40cc in that time.
 

f-e

Well-known member
Mentor
Veteran
What you need, is a butt pump. It will give you loads of lift. It will be trickling out

https://www.amazon.com/Hozelock-2826P8000-Water-Butt-Pump/dp/B000PBWCTQ
£60 on eBay. The new version has the same spec. Namely the '11 meters of head' pressure. Hozelock know their shit. They don't even say how many gallons it moves on the box. Just that it's 1.1 Bar. It's the small-print where it says 2200L so 550usg. Making it suitable for about 100 Gallons with a favourable setup.

It's hard to find a mains powered pump that makes the pressure without trying to empty a swimming pool per second. 300w is still far too big.
 

mikeross

Member
I always thought bigger pipe means bigger pressure. Going from 1" to 1/2" will reduce PSI right? Either way, pipe size isn't going to solve your problem. If you want to create pressure you need a diaphragm pump. GPH, especially concerning submersible pumps is a terrible way to measure PSI. Most, no matter how large won't create the PSI you need for pressure compensating emitters to work as designed.

Anyways, why do you want to run pressure compensating emitters? I think your better off with a loopfield or "pico" style manifold with open ended 1/4" lines. Just make sure your main loops and all your 1/4" open lines are the same length. Your pump is more than enough power, in fact you might have to tee off in your rez with a shutoff valve to control flow as it might be to much... this valve even left slightly open will also act as your siphon break if you keep it above the waterline.

Emitters clog... Don't see why you would want to use them if you don't have to.
 

alpo

Active member
I always thought bigger pipe means bigger pressure. Going from 1" to 1/2" will reduce PSI right? Either way, pipe size isn't going to solve your problem. If you want to create pressure you need a diaphragm pump. GPH, especially concerning submersible pumps is a terrible way to measure PSI. Most, no matter how large won't create the PSI you need for pressure compensating emitters to work as designed.

Anyways, why do you want to run pressure compensating emitters? I think your better off with a loopfield or "pico" style manifold with open ended 1/4" lines. Just make sure your main loops and all your 1/4" open lines are the same length. Your pump is more than enough power, in fact you might have to tee off in your rez with a shutoff valve to control flow as it might be to much... this valve even left slightly open will also act as your siphon break if you keep it above the waterline.

Emitters clog... Don't see why you would want to use them if you don't have to.

to control the rate so it waters the media more evenly.

I ended up buying parts for a floraflex micro drip set up on their cyber Monday sale
 

f-e

Well-known member
Mentor
Veteran
Hmm... lets do the math..
100 fully working 0.5gph drippers placed along 100 foot of 1/2" hose will see 0.8psi lost by the end of the line. That's a 5% fluctuation across the room (because fully working 0.5gph means 15psi). People generally plumb the top of the slope first, so the end of the run is at the lowest point. 50cm of slope would be needed to get that 0.8psi back again. Or much easier, loop the pipework to form an equal pressure manifold.

The slow delivery of drippers is needed to fully soak a pot until it just can't hold and water tension breaks, letting quite a bit drop out in one go. That action help get air in. The time taken helps salts dissolve, ready to get flushed out to. While a drip stake is a very easy way of fixing the pipework in place.

Studies show that more drippers per pot is better. Salt levels within pots show this, where it's a lot better under the dripper where it's water goes. So it's nice to have all your drippers working within a small margin as who wants to balance the flow of 100 emitters.

I wouldn't put dirty water through drippers. If it's recirculating then I balance up open pipes. Nor would I run without a filter because filters do catch bits that would otherwise block drippers. It's also good practice to put at least 2 drippers per pot incase one did block. Though that is sooooo rare I have not personally had it happen.


Positive displacement pumps are very cheap and easily reach beyond the pressure we need. I haven't seen a submersible one though and using taps to set the pressure has that problem of blocking. Where if the return blocks, the pipework see's maybe 70psi, so barbed connections can't be trusted. The pipework needs physically fixing down as it will try and straighten and may even shove a dry pot at such pressures. Frankly I'm anxious about these little complications and really do like a submersible. It's just tidy and quiet (well can be quiet)
 

alpo

Active member
I always thought bigger pipe means bigger pressure. Going from 1" to 1/2" will reduce PSI right? Either way, pipe size isn't going to solve your problem. If you want to create pressure you need a diaphragm pump. GPH, especially concerning submersible pumps is a terrible way to measure PSI. Most, no matter how large won't create the PSI you need for pressure compensating emitters to work as designed.

Anyways, why do you want to run pressure compensating emitters? I think your better off with a loopfield or "pico" style manifold with open ended 1/4" lines. Just make sure your main loops and all your 1/4" open lines are the same length. Your pump is more than enough power, in fact you might have to tee off in your rez with a shutoff valve to control flow as it might be to much... this valve even left slightly open will also act as your siphon break if you keep it above the waterline.

Emitters clog... Don't see why you would want to use them if you don't have to.

the smaller pipe will reduce psi but does the supply line size matter if the manifold pipe size is smaller?
 

alpo

Active member
Hmm... lets do the math..
100 fully working 0.5gph drippers placed along 100 foot of 1/2" hose will see 0.8psi lost by the end of the line. That's a 5% fluctuation across the room (because fully working 0.5gph means 15psi). People generally plumb the top of the slope first, so the end of the run is at the lowest point. 50cm of slope would be needed to get that 0.8psi back again. Or much easier, loop the pipework to form an equal pressure manifold.

The slow delivery of drippers is needed to fully soak a pot until it just can't hold and water tension breaks, letting quite a bit drop out in one go. That action help get air in. The time taken helps salts dissolve, ready to get flushed out to. While a drip stake is a very easy way of fixing the pipework in place.

Studies show that more drippers per pot is better. Salt levels within pots show this, where it's a lot better under the dripper where it's water goes. So it's nice to have all your drippers working within a small margin as who wants to balance the flow of 100 emitters.

I wouldn't put dirty water through drippers. If it's recirculating then I balance up open pipes. Nor would I run without a filter because filters do catch bits that would otherwise block drippers. It's also good practice to put at least 2 drippers per pot incase one did block. Though that is sooooo rare I have not personally had it happen.


Positive displacement pumps are very cheap and easily reach beyond the pressure we need. I haven't seen a submersible one though and using taps to set the pressure has that problem of blocking. Where if the return blocks, the pipework see's maybe 70psi, so barbed connections can't be trusted. The pipework needs physically fixing down as it will try and straighten and may even shove a dry pot at such pressures. Frankly I'm anxious about these little complications and really do like a submersible. It's just tidy and quiet (well can be quiet)


Grodan recommends only one drip stake per 4" (two for 6") rockwool cube @ 0.5gph. But I guess if my pump won't be putting out 0.5gph I will just use two drip stakes.
 
Top