How much head pressure do I have?

Reef Aquarium & Tank Building Forum

Help Support Reef Aquarium & Tank Building Forum:

T

tylert

Well-known member
Joined
Feb 10, 2009
Messages
86
Location
huntington beach
Do you include the loc-line?
From the pump to the two returns is 57". From my pump I use 1" ID flexible plastic tubing that goes up 47" through a check valve. It then splits in a "Y" with each side going up 22" to a hard PVC elbow attached to 1" bulkheads. Then I use reducer bushings to add the 3/4" loc-line, each loc-line is split in two with about 9" on each end.

So that's 3 feet of loc-line which I don't know if I should include. Also, I'm not sure how much to add for each 90 degree elbow, I've been told between 1' to 2' each. And then there's the tricky part of reducing it from 1" to 3/4". I've been told to add 25% to everything If I reduced the line at any point, but it is at the very end in the tank.

So for anyone helping that is:
91" of plastic hose
3 feet of loc-line
2 hard elbows
1 check valve
and 1 "Y" split

the height is 56" from pump to returns with 52" of horizontal plumbing. (not including loc-line)

I'm thinking it's between 11' and 14' all together but if anyone knows let me know, any help is appreciated

thanks, Tyler
 
The loc-line probably won't really factor in to your head pressure other than a really minimal amount of friction loss and latteral head. 3/4" loc-line flows at 1140 gph, so a lot of it will depend on your pump size. I would venture to guess you're looking at about 10.75' of head with a pump rated in the 2200-2400 gph range. Slightly less with a smaller pump.
 
I used that calculator and it said that I only lost 8.26' of head loss with the locline and 8.12 w/o. At a flow rate of 760 GPH with my mag12

I don't know if that's right, it seems like a low estimate of pressure, the flow out of my locline seems really low which is why I posted this thread in the first place. And I didn't know the head pressure changed depending on the pump strength, that's huge.
 
I don't think so, tht sounds about right, and if you think about your low flow coming out of the loc-line it makes sense. If you're only getting a total flow rate of 760gph at that head pressure coming out of 4 outlets, that would equate to a mere 190gph per outlet. OUCH! A couple of things you can do to bump that up without having to fork out too much $$$ would be to reduce to a 3/4x1/2x1/2" loc-line Wye rather than 3/4x3/4x3/4" (your total flow will remain the same, but you'll get more pressure out of each fitting), add flow accelerators to your nozzles (some people bag on em, but I've used them and they DO work), add a second pump and run one to each return, or buy a second pump and use it as a TRUE closed loop wich negates almost all head pressure minus friction loss due to pipe material/bends/pipe diameter. Otherwise you're looking at buying a bigger pump if you want to achieve more overall flow.
 
Not if your already cutting your flow in half by the time it even reaches the loc-line. The head pressure you have even without the loc-line installed is reducing your overall flow to around 760gph. Now a 3/4x1/2x1/2 loc-line wye is going to have a maximum flow rate of 1140gph at I believe it's 4.4psi. 3/4x3/4x3/4 loc-line wye's have exactly the same flow rating because of the single 3/4" input. The difference is the pressure on the output side. By reducing the output size on any wye fitting you can increase the output pressure without affecting output volume, as long as the combined output's ability to move water is greater than the single input. So in other words two 1/2 pipes have a greater capacity to move water than a single 3/4 pipe does. since the inlet to your loc-line wye is 3/4 inch, that sets the maximum flow that can be achieved through that wye. So unless the outputs were restricted to 3/8" or smaller, it will have no bearing on head pressure.

Another way to look at it would be like taking a 1" pipe, reducing it to 3/4", and then expanding it back out to 1" again at the output. That's essentially what a 3/4x3/4x3/4 loc-line wye does. A 3/4x1/2x1/2 wye would be like taking a 1" pipe, reducing it to 3/4" and that is all. No re-expansion.

Now, the benefit, lke I said would be the increase in pressure at each outlet, not an actual increase in flow. However, this would allow you to sort of target your flow to a smaller area if you have some more flow demanding corals.
 
Ok cool sorry if sound dumb, I just wasn't sure what you meant by 3/4X1/2X1/2. You mean keep the 3/4 Y locline piece but reduce each branch of the Y to 1/2?
Also do enductors make a big difference versus the spray nozzle?
I think I'm going to take your advise but also suppliment with 2 or 4 powerheads. My main goal is to have flow pointing down behind the rocks flowing debris out of the sides on the bottom then have bottom flow angled slightly upward, then mid flow angled slightly up, the surface flow to bring it to the overflow. With my locline I was hoping to have 2 nozzles for surface flow and 2 nozzles pointing down to get behind the rock.
Any sugestions on the powerhead size or placement, and does that sound like a good plan for flow?
 
Yes, and Yes, the eductors will dramatically increase head pressure, but because you're getting a venturi effect, they will boost overall flow. The majority of it however will be comprised of water that is already in your display. It will slow down the flow through your sump (which isn't neccessarily a bad thing) though. I might rethink your idea on the upward flow though. The reason I say that is you want as little surface turbulance as possible to ensure that the nasties stay on the surface where the gravity feed from your overflow will draw them over. The more surface turbulance you have, the more likely you are to break the surface tension I guess you'd call it between the nasties and send them back down into the water cloumn. The overflows will do the work, focus your nozzles and powerheads on stirring up what settles in the column and it will rise to the top on it's own.

As far as placement goes, you want to create laminar flow by directing nozzles and powerheads at angles where their sprays will intesect and colide. This will keep the flow more turbulant for your corals rather than a constant linear flow in one direction. As far as size goes, that really depends on tank size and what you are, or are planning to keep in it.
 
If you're wanting to keep SPS I'd recomend a total flow of at least 30x maybe even closer to 50. 90x30=2700gph. Subtract the 760 you already have and you have to come up with another 1940gph from powerheads. A couple of Koralia 3's or 4's would be sufficient in this case. To get closer to the 50x range, you would need at least three Koralia 4's or 4-5 Koralia 3's. By the time you weigh the cost of the powerheads and their combined power consumption, as well as how visible they'll be in the display, you may consider doing an overhead closed loop system with a single reeflo dart/barracuda or something to that effect. A Dart on a closed loop where there's virtually no head pressure loss would put you at 50x flow combined with the pump you're already using for your sump returns.

I run my 240 at a little over 30x but I don't have a lot of sps. Mostly LPS so I can get away with it by placing my sps in areas where the flow is a little stronger. I will say based on experience though, that even my softies seem happier with 30x flow versus less with exception of a few mushrooms.
 
Last edited:
So I shouldn't angle them upward? how would you put the powerheads? should I have locline flowing across the suface?
 
I wouldn't have anything pointed at the surface. Put your power heads in opposite corners of the tank angled at about 45 degrees right to left, and place them up high in he tank, angled down about 30 degrees, then point your locline in a manner that will intersect the flow from the powerheads.
 
Not a problem at all. Having the powerheads pointed slightly down will take care of most of the detritus on the sand, however I still recomend using something like a wood paint stirrer or something to stir the top couple of inches once a week or so, and just before doing water changes.
 
Ok. I have 2 Koralia 4's (1200gph) and a Seio 2800 (2800gph) and my locline up in each corner which we know sucks and only puts out about 200 gph on each of the 4 hoses. That's 6000 gph which is a rediculous amount of flow for my 90 (about 67xper hour). I don't know how to incorporate my Seio or how I would set everything up but if I omit it then I will only have 3200gph or about 34x per hour. What would you do? Should I just leave out the Seio? How would I set it all up?
 
Should I have my Koralina's in the middle pointing down to the outside and my locline in the corners pointing down to the inside?
 
That would be fine....you'll probably just have to play with the placement a while until you get the flow you want exactly.
 
You must log in or register to reply here.

Similar threads

P
310 Tonga Tank
2
Replies
34
Views
12K
captain1
C
Vandur
40g Breeder, Tank Build(s)
Replies
16
Views
14K
spieszak
spieszak
S
Micro air
2
Replies
32
Views
2K
HUNTER01975
HUNTER01975
A
Help change the way Brine shrimp is kept/sold at a store.
Replies
14
Views
3K
kpiotrowski
kpiotrowski
S
New build, recap of old build and lessons learned
Replies
13
Views
5K
seattlereef
S

Latest posts

Back
Top