open spaghetti pvc manifolds discussion

[smurfin'herb]

Hello. Ive been experimenting with several different manifolds with different sizes of tubing and pumps etc.. Ive asked questions to people about how these work, but i always get the same reply... " Just build a manifold that is evenly proportioned and space the drip lines evenly and identically on each line of manifold and they will all emit evenly if u have the right size pump". So i have done this with 3/4" pvc, and 1/2" hosing. Both times, i get the same result even using various size pumps. All hoses emit water, but not evenly. I put cups under each drip head and measured each one to figure this out. What i discovered could have easily been predicted. Water, as well as multiple other things, likes to take the path of least resistance, and theres nothing you can do to change that. So if your manifold is on the same slope as your drain table, more water will be distributed towards the front, than the back. I havent got round to it yet, but i think u should be able to solve this problem by making the manifold perfectly level. This would mean that it woud be almost impossible to make a perfect open manifold out of hosing, because it tends to sag/bend and be uneven. This whole deal probly isnt as big of a problem for reirc. open ended drip systems, but it is for people who use coco or rockwool in a drain to waste setup. I havent heard any discussion on this here, but if i missed it please re-direct me. thx

 

[smurfin'herb]

I was also wonderin how they get even distribution on the the vertical open end drip units. It seems impossible without some sort of pressure compensation...

 

[LiLWaynE]

putting the manifold level with the pump coming from the middle (like a T) seems like it would SOME sense...

maybe my reply will help bump ya to someone with experience in this area though...

 

[freeradical]

1/2" tubing seems very large (especially for many plants). How many tubes are coming out of the manifold? What size pump are you using? I've always heard of people using 1/8" lines. This would help keep the manifold under pressure, allowing for more even water distribution.

 

[Bozo]

I use a manifold of my own design not sure if others make them like this . 2 inch pvc capped on the end,1/2 barb fitting on other.I drill and tap pipe and install 1/4 in or 1/8 barb fittings .I keep all lines same length .I have never measured lines but I am almost possitive it is more even than long pcv manifolds

 

[BlindDate]

Smurf....Use a high pressure pump (50 to 100 psi) and all your problems will go away.

 

[ShroomDr]

The manifold needs to be under (some) pressure, to assume equal output at equal lengths of tubing. I Bet you are not pressurizing your 3/4".


Here is a 1/2" manifold, 1/4" output tubing.

 

[badugi]

That's what I said.

You're trying to feed too many sites with too small of a pump.

 

[smurfin'herb]

Smurf....Use a high pressure pump (50 to 100 psi) and all your problems will go away.

I use a 1000gph pump with a 4x8 manifold made of 3/4'' pvc with about 72 drip lines, is that enough? Im not sure how to convert gallons per hour into pounds per square inch. anyone...?

 

[icough2getoff]

I have been wondering this same question. I look forward to following this thread.

 

[BlindDate]

I use a 1000gph pump with a 4x8 manifold made of 3/4'' pvc with about 72 drip lines, is that enough? Im not sure how to convert gallons per hour into pounds per square inch. anyone...?

You cannot convert GPH to PSI since some pumps are made for pressure and others are made for flow. You can convert "Head" pressure to PSI and that is a common stat given by all pump manufacturers. But, if you are using a pond type pump the pressure is almost nothing.

 

[BlindDate]

Example:

A 950 GPH Pondmaster Mag Drive pump will do 14' head pressure.

This equals only 6 psi.

That is why pond type pumps will always give such poor distribution. Like I said: buy a diaphragm pump and use drippers. When you put 50 psi behind them, everything is even.

 

[smurfin'herb]

finally the answer to my main q! i figured there had to be some maximum flow rate for the 1/8 inch lines. but i was kinda worried that they were gonna spray super far and to fast for the medium to absorb it. So if i buy a sump pump, does it come with an atttachment for a 3/4 hose? i want a 1000-1200gph sump pump right? or 50-100 psi pump? what do i look for, GPH, OR PSI? thx again

 

[freeradical]

Also wondering what to look for exactly in a dripper pump, as I'm in the market for one. Not pulling up much by searching for diaphragm pump. Do they make submersible diaphragm pumps?

 

[smurfin'herb]

So i went to lowes and home depot today. They have sump pumps and then they have utility pumps. Which one would work better for my situation..? The lowest rated sump pump they had was like 3,000 gph and was eqipped with a float valve on it,...... wouldnt that mess with what im trying to use it for? Wouldnt 3000+ gph would be too much pressure for a 4x8 manifold with 72 drip sites? lil hlp pls

 

[BlindDate]

For the 100th time, gph is NOT pressure.

This is the kind of pump to use:
http://www.rvpartscenter.com/ProductDetail.asp?ProductID=26197&StoreID=36&DepartmentID=11&CategoryID

 

[smurfin'herb]

where can i get that at around my area? lowes and home depot only have sump pumps and utility pumps... neither have psi ratings, only gph and horsepower...

are the rv pumps the same as the utiity pumps, or pond pumps? Ive read a lil about pond pumps, piston pumps, perstilatic pumps, rv pumps, sump pumps, utility pumps, and still dont know whats what!! Ive never used any pumps besides the sunleaves ones... Im sorry but im really confused. From what ive read is that sump and pond pumps are designed to move water vertically, and do not use much pressure, is this correct? And are pond pumps the same kind of pumps they make for ebb and flow tables? Please help me clear this mess up! thx guys! All i want is a pump that will max out the pressure on all my 1/4" feed lines on my 3/4" 4x8' manifiold with 72 drip sites. And i need to be able to find it locally. thx again s'h

 

[freeradical]

smurfin'herb, keep in mind BlindDate recommends drippers for use with a diaphragm pump. Although the distribution is guaranteed to be even, you have to buy a buttload of drippers. I'm in the same boat as you, I am looking for a drip system for 64-128 sites. I'm debating going with a bed of coco and using a high pressure pump with a soaker hose, but this may be more trouble than I want. I want to avoid using drippers and use 1/8" open lines from a manifold, but have no idea how to keep the distribution even with open lines.

 

[freedominphilly]

I'm not sure if this is much help. But I use a 1900 gph pond pump i bought at lowes. I feed 180 plants, 60 at a time, with no problems. Take a look at the 3rd or 4th page in my sig, it will show how I do mine. Here's the link http://www.icmag.com/ic/showthread.php?t=100170&page=8&pp=15

 

[smurfin'herb]

So let me get this straight. If i use a large enough pump to create the max pressure in my manifold thru the feed lines then i will get even distribution because each line is at its max psi rating. So if this is true, why are all theses people making manifods for purpose of even water distribution, when you could just run a line of hose/pvc, cap it off at the end, and install feed lines...? Now i have two more q's....

What is the max psi rating for 1/4'' feed lines?
What is a Diaphragm pump? is it a sump pump....?