Question On Return Flow Pressure

I

Ivan

I have an Oceanic tank with dual overflow. On the return, I have a single flow loc-line on each side. I've been considering getting a dual loc-lines for each side to gain additional variable flow in the tank for my SPS. My question is this: will dual loc-lines decrease my return flow, or will the additional return outlet allow the pump to work more efficiently because it will allow more flow?
 
its not going to allow more water unless the return line itself is larger. its purpose is to allow you to spread out the return flow to more than one spot. it will actually decrease your flow because any extra peices you add to the mix will add back pressure and reduce flow. of course it will be very minor from a peice like this though.
 
The flow in the tank should be done by the powerheads, not the returns. So long as the returns are pumping in enough water (turnover), say 3-5x, that is all you need. Rely on the powerheads for the movement of water inside the tank itself. Splitting it won't reduce the flow into the tank, but its not going to make a difference on flow inside the tank unless you have a jacuzzi action going.
 
@DaveJ wrote:
Splitting it won't reduce the flow into the tank said:
I think what Wes means is it will decrease the velocity and pressure and that is correct. It does change the flow patterns as well.
The velocity from our pumps we use do not effect pressure loss on a 3/4" pipe that much unless you are pushing a lot of volume. I'm not at work right now but I can guesstemate that 10 gpm through 3/4" pvc is around .05 psi/foot and take out about 8' of pipe for each elbow. I wish I had an icon of someone sleeping to go here.
Anyway you might try penductors or eductors to change the flow characteristics.
Click to expand...
 
@timthetoolman wrote:
[I]@DaveJ wrote:[/I][quote=" Splitting it won't reduce the flow into the tank said:
I think what Wes means is it will decrease the velocity and pressure and that is correct. It does change the flow patterns as well.
The velocity from our pumps we use do not effect pressure loss on a 3/4" pipe that much unless you are pushing a lot of volume. I'm not at work right now but I can guesstemate that 10 gpm through 3/4" pvc is around .05 psi/foot and take out about 8' of pipe for each elbow. I wish I had an icon of someone sleeping to go here.
Anyway you might try penductors or eductors to change the flow characteristics."]

All of that depends... a pressure rated pump will react to head pressure/restrictions differently than a flow rated pump. It probably won't be that much of a difference that it would be noticeable. :wink: Penductors/eductors definatedly require a pressure rated pump in order to reap their full potential. :)

Cheers,
Click to expand...
 
@timthetoolman wrote:
[I]@DaveJ wrote:[/I][quote=" Splitting it won't reduce the flow into the tank said:
I think what Wes means is it will decrease the velocity and pressure and that is correct. It does change the flow patterns as well.
The velocity from our pumps we use do not effect pressure loss on a 3/4" pipe that much unless you are pushing a lot of volume. I'm not at work right now but I can guesstemate that 10 gpm through 3/4" pvc is around .05 psi/foot and take out about 8' of pipe for each elbow. I wish I had an icon of someone sleeping to go here.
Anyway you might try penductors or eductors to change the flow characteristics."]

I know what he meant... regardless though flow inside of the tank, be it variable, direct or blow the skin off SPS fast should be done by the powerheads NOT the returns. The returns functions are simply to put water back into the tank, not movement, not wave action, not velocity.. fill the tank period.
Click to expand...
 
if you want to increase your flow buy a Flow accelerator

http://www.marinedepot.com/ps_searchItem~IdCategory~~parsed~1~SearchText~accelerator,pacific.html
 
@DaveJ wrote:
I know what he meant... regardless though flow inside of the tank said:
That's very true. He could use a squid or a Oceans Motion on the return to get a better wave action for the corals but it's no where near enough by itself.
Ultimately Dave, I took your suggestion and got the Vortecs which made a big difference even though my pump is pushing around 1200 gph it was not enough through the OM to get the right wave action. I was a little disappointed that big of a pump didn't make as much difference as power heads.
Click to expand...
 
@timthetoolman wrote:
[I]@DaveJ wrote:[/I][quote=" I know what he meant... regardless though flow inside of the tank said:
That's very true. He could use a squid or a Oceans Motion on the return to get a better wave action for the corals but it's no where near enough by itself.
Ultimately Dave, I took your suggestion and got the Vortecs which made a big difference even though my pump is pushing around 1200 gph it was not enough through the OM to get the right wave action. I was a little disappointed that big of a pump didn't make as much difference as power heads."]

Apparatus like the oceans motions and the like are best in closed loop systems in my opinion... since you are using a high head pressure pump to drive your flow. Regular setups where you are using the returns and powerheads, the better choice is to go with powerhead options and leave the returns as simple returns. 1200gph sounds like a lot, but when you put it against 3000 or 4000 on a high quality powerhead like the vortec or tunze, its just a drop in the bucket. While you can still use powerheads in a closed loop for additional flow, the main movement is done by the loop itself with powerheads augmenting them or just adding more to an already busy flow system to break it up.

Honestly with the powerheads available today, I am not even sure why people bother with things like that since the available flow and optional settings offer up so much flexibility and flow out of the box. People stick 24" wheels on pintos though so gadget mania plays into it. Those devices look and sound cool, but proper choices and design matter much more.

Glad the vortec helped out... I wasn't sold on mine after replacing my tunzes, but now that I have had them for awhile, I like them much better for many reasons and probably would never go back to tunze in a larger system. I still love the nano 6055's in my frag tank and 92, but anything larger would be vortec all the way.
Click to expand...
 
Yep, it seems to have turned out to be a 'tinker toy' (the OM) but I do like the random wave patterns it gives me with the Vortecs. I would not have bought it but it came with the pump so I plumbed it in.

Ivan, sorry to hijack your tread. :D
 
Whats wrong with creating all of the flow with the return pump? I have done it on both of my reefs... (150 gal and 100 gal)

I have nothing but 2 returns with loc-line on each tank, and it works great.

I wanted a no clutter, no power heads, no junk display area, and I have accomplished that with great results.
 
not generally the best to have alot of flow through your sump/refugium...not the amount needed for SPS anyways. also, it is hard to cover all areas of tank and prevent dead spots where nasty's can build up with only returns.

next wave will have a presentation on why "flow is more important than light" that should be interesting and actually answer this exact question.
 
@aentrop wrote:
Whats wrong with creating all of the flow with the return pump? I have done it on both of my reefs... (150 gal and 100 gal) I have nothing but 2 returns with loc-line on each tank said:
The amount of flow needed for many (not all) tanks is nearly impossible with returns. In a LPS or softy tank, you might be able to get enough, but even then the flow is much more directional, than it is wide and dispersed. Directional flow is much different than varied and random flow patterns. Even with loc-line heads like the fan etc, your flow is still very directional. You can split it into 2/4 etc to get the effect, but flow into the middle levels of the tank, or lower portions of the tank are quite different going from top down as opposed to the sides out, or across the sides.

As I said above.. the purpose of the returns is simply to keep water going into the tank, not to create flow or movement. If it works for you, wonderful, but the majority of people needing flow in a tank will find it lacking in movement and total flow and will have dead spots all around the tank.
Click to expand...
 
Understood, thanks for the quick response!

One comment I do have is that I have a seperate valved refugium so I have adjust the flow in the fuge from 99% of the return water all the way to 0%...

and the remainder (whatever's not going to the fuge) goes to the sump. Does it matter how much water flows through the sump?

and sorry to temporarily hijack your thread but you got me interested in some things now...

How does the flow passing by the pump of a skimmer affect it's skimming abilities? I've read that you want low flow for the skimmer, but its all the same water, no matter how fast its flowing.... right?
 
@aentrop wrote:
Understood said:
Flow through the sump, not really, though that is also your flow rate from/to the tank so not too fast. The general rule of thumb, which is varied since I like a bit more than that, is 3 or 5 times the tank size. That limits the amount flowing into the sump the same.

Flow into the fuge, depending on size, should be relatively slow. Enough to keep it moving and not stagnant etc... but not enough to where you are pushing stuff out of the fuge into the sump. The slower flow allows better reduction (or more efficient) of nitrates into the macros etc.

For the skimmer, it depends on the type of skimmer. Most, not all, have an ideal flow rate into the chamber. To maximize your skimmer efficiency, you should have an idea of what your skimmer can handle per hour and only put that into the chamber, or slightly higher.

If you follow the 3 to 5 times, or up to 7 like I run then all of that should take care of itself, except the fuge amount which I cut in half or more.
Click to expand...
 
I run about a 20x turnover on a 100 gallon tank. It a dolphin 3500gph pump @5.5' head pressure.

So about 2-3x goes to the fuge, and about 18x through the sump.
 
@aentrop wrote:
I run about a 20x turnover on a 100 gallon tank. It a dolphin 3500gph pump @5.5' head pressure. So about 2-3x goes to the fuge said:
My opinion thats too much, but if its working for you thats what counts. I suspect your skimmer, if its not a recirc model, is probably not skimming as efficiently as it could though. The amount going into the fuge sounds about right so long as its not a huge fuge.
Click to expand...
 
it is a big fuge... it holds about 25 gallons of water.

My skimmer is a Red Sea Berlin Skimmer, 250 gallon rating...

Any comments good or bad?

How does high sump flow make the skimmer not as effective? (Not sarcasm, I am really curious and don't understand...)
 
@aentrop wrote:
it is a big fuge... it holds about 25 gallons of water. My skimmer is a Red Sea Berlin Skimmer said:
25G I would probably target 300-500gph.

The skimmer issue as I understand it deals with the amount of water flowing through the chamber and the availability of that water to be skimmed. While all the water in the system will eventually find its way into the skimmer, its not as efficient if it has to be sucked in as it goes racing through the chamber as it would be if it hung around in it longer. Its similar to the water moving through the fuge having more time to be processed by macros.
Click to expand...
 
You must log in or register to reply here.
Top