flow rate queastion

[speedyrb29]

ok im trying to figure out what size pump i will need to keep everything going good. i have a 75 gallon with a single megaflow overflow and a model 3 megaflow sump. what mag drive pump should work with this setup? the sump is located directly under the aquarium has to travel up probly about 4 feet tops.

 

[ronj]

i have a 72g w/ a mag12 running my closed loop....i don't have a sump, but the flow should be similar..it is perfect for my tank...how many gph is your overflow rated at???? you might could go w/ a mag 9

 

[kinghokus420]

i have a 72 with a model 1 sump and use a mag9 with good results. somewhere around 700 gph. i returned mine over the back with 1 1/4 pvc and it seems to flow good. the internal megaflow overflow is rated around 600 gph iirc. i use the 3/4 bulkhead as an emergency overflow standpipe. it sits about an inch above the overflow water level, just in case the main drain gets plugged.

 

[mungus]

Your overflow is rated at 600 gallons an hour. You probably want to be a little bit lower than that just incase something gets in there that would block the flow. If you are thinking internal I would recomend a mag pump. If you are thinking an external I would go with a blueline or Iwaki. Here is a calculator to help you figure out your head loss. http://www.reefcentral.com/calc/hlc2.php

Brian

 

[speedyrb29]

what if i got a pump to big could i use a ball valve to cutdown the flow?
also if im thinking about going closed loop should i get a pump with more flow?

 

[returnofsid]

Speedy...I'm in the process of trying to do something similar and have a thread going for that. From what I've learned, installing a ball valve to cutdown flow is possible but may put too much back pressure on your pump and could damage it in the long run.

 

[ClamLubber]

I'm guessing we have the same tank. The overflow compartment has two hole drilled. the larger one is for the "j" shaped tube that drains to the sump the other one is for the return. What I have done is run the gravity fed tube to the sump and have a mag 5 returning that via horizontal 3/4" pvc tube with three 1/2" tee's. I use the other bulkhead to feed an external pump that should be delivering >1000 gph that returns to the system via a u shaped manifold that runs the sides and front lip of tank with 6 1/2" tee's. Each Tee is fitted with a short tube which is capped. I used a table saw to cut a slot in each cap. Between the two pumps I should be getting 1400gph which is the 20x tank volume I see recommended the most. Is working very well.

 

[mungus]

Yes you can use a ball valve to control the flow. You would only want to put the ball valve on the output. Never try to control the flow with a ball valve on the input. It will wreck your pump. You can also run some extra pvc back to your sump to route some of the water back there or to a refugium. As far as a pump for a closed loop you will want something with a high flow rate and low energy consumption. Head pressure is not an issue with a closed loop.

Brian

 

[speedyrb29]

clamlubber do you have any pics of your set up it sounds good.

 

[ronj]

wait ... you are doing a closed loop or a sump return pump?????? also, Mungus, how is head pressure not an issue w/ a closed loop? it still has to travel 4' back up to his tank...i use a mag12 w/ my closed loop. i too have 4' of head loss. my pump is only putting out 900gph (just estimating) after head loss..if he gets a pump too small, he will end up w/ no flow from the closed loop

 

[mungus]

Here is some info on closed loop

In a CLOSED LOOP SYSTEM the pressure of the water in the main tank is pushing the water through the Bulkheads or "drains" to the inlet of the pump and the return line is also below the surface producing Zero Static Head Pressure creating a CLOSED LOOP. The pump doesn't have to work as hard and reaches its maximum flow minus elbow or wall friction.

It doesn't matter where your intake or outputs are as long as they are below the display water surface. And it doesn't matter where your closed loop pump is or how far the inlet and outlet destinations are.

The only factor that reduces flow is remaining friction loss, which can be as much or more than static head if you don't plan your plumbing carefully.

 

[ronj]

i don't believe that a pump sitting level with the tank and a pump sitting 4' below it have the same pressure ....one of them is going to be straining because of the upward flow...now i guess you are refering to a closed loop through an overflow drain????? i have a closed loop that is hanging on the back of my tank(not reef ready tank).it has to create a siphon...i think we are talking about two different ways to make a closed loop, but i still don't see how there would be no head pressure going uphill on any setup

 

[ClamLubber]

I'll try a shoot a pic or 3 tonight. Fortunitely the tanks are in a wall and I have a room to access them from in the rear so I should be able to get good views. I covered the tank back with black posterboard, but left the portion with the overflow open to be able to see the plumbing.

 

[speedyrb29]

ok a thought i had todfay was to have the water go into my sump from the main tank threw the hole on the bottom and instead of making it go back up from the other hole have it go to a fuge and from the fuge have the water go to the tank and split into to heads then with the unused bulk head hole in the bottom make it run to the top of the tank and make it split into 2 heads so ill have 4 heads for flow but ill need 3 pumps to make this work.

 

[ClamLubber]

Ok here goes nothing....
The manifolds are adapted form Anthony Calfo's discription of closed loop. In his book (Propagation of Reef Corals - a must read if you don't have it) the return comes up to a T and the water can circulate around a loop of PVC with T's every so often. My closed loop manifold is a U going down each side and the front of the tank. It is made of 3/4 inch pvc but the T's are the type that reduce the offshoot to 1/2" so the spouts (4 to a side) are 1/2". The back of the tank has a straight tube with a T to the right of the overflow, a second left of tank center, and at the elbow at the end of the tube. ~400gph split 3 ways isn't a lot of velocity but it is pointing down on the top of the live rock so I didn't want to blast it too hard. I may cap off the center one later if I need a stronger flow.

The spouts on this tank currently were made by heating a section of PVC pipe with a torch and crimping with pliers. I then cut the tube at the base of the crimp to get a slit and sanded of the burnt pvc Since then I have changed over to cutting a slot in a pvc end cap. I made a jig from a piece of 2x4 and drilled holes down the center line big enough to fit the caps into them closed end down. It held 6 caps for one pass over the saw. I secured each into its hole with a wooded wedge so they wouldn't pop out. I set the fence on the saw for slightly off center and made a pass with each side of the block against the fence to get a slot a little over the kerf width of the blade. I joined these without cement to a 45degree elbow. These are inserted to the t's of the manifold and can be swiveled to direct flow.

I spray painted them black so they blend with the black back wall of tank. They have to be submerged a little to prevent bubbles from being sucked in with the flow, but need to be shallow enough (at least one) to suck air up as soon as the water level drops if the pump is turned off so they do not siphon too much into the sump. That is esp true of the sump return since the water level doesn't change that much when that pump stops and the closed loop is still running. I am going to drill a hole in one of then pretty soon so I can point it a little deeper. You can see the ripples at the right of the pic above where that last spout is really shallow at the moment.

The details of the overflow plumbing are here:

If you can't read labels on above

The CO2 tank is in the way, but there is a little giant external pump behind it under the tank that gets fed from the short pipe at the bottom (which was meant to be the bulkhead for returning water back into tank) and returns to the U shaped manifold. The tube has been slotted on the table saw and capped to keep things from sucking down into the pump. (like the 3 snails that went over the wall yesterday and had to be peeled off the slits. Dumb little turbos) The standpipe feeds the one inch upside down U you can see going into the front corner of the sump. It empties right in front of the intake to the ASM G3 skimmer. Slightly diferent angle of same:

The ball valves on the sump return are not for restricting flow but for redirecting it. I can open the lower one and close the upper to keep flow cycling through the sump while tank is being fed. I also have a set of QT's above the 55gal sump that can be filled from the other end of the line by opening valves there with the tank return valve off. I then replace the water sent up to the QT's with fresh for the weekly water change.

The 55gal tank I am using for sump is partitioned for the 12" section for the ASM G3 you can see. That section spills over into the center section (30"long) with a 8 inch DSB/lighted refuge which overflows into a 6 inch section at the other end with a eggcrate platform on the back half for carbon and poly filter and under/beside that sits the Mag-5 that powers the return. Water levels in the sump and DSB sections stay level. The final 6 inch section drops with evaporation and that is where the top off controller will be going as soon as I get around to ordering it. I have to order some Cheato for the center section as well.

I have the luxury of an 8x8 ft room behind the tanks that all the sumps and filtration stuff in laid out in. The wall displays the 75 shown here at lower left. a 55 fish system above it and 2 25 gal tanks to the right side. The upper tanks have a similar set up with a 40 long tank as DSB/refuge and the lower 25 has a 20gallon of it's own.


Ok... time to hold my breath and sumbit. Hope the images make it. It is my first time to do that.

 

[ClamLubber]

OMG the images are huge !!!!! Oh well still so much to learn, hehe. at least they made it.

 

[speedyrb29]

ok i think i know what im going to do now. like clamlubber im going to runa closed loop from the extra bulkhead. but know i have to figure out how i am going to plum my sump and fuge the stand pip is 600 gph droping like 4 feet into the sump then i need to get the water from the sump into a seprest tubberware container that is the fuge ill need a pump to do this and then i need a pump to get the water from the fuge to the tank. no i need to figure out wat pumps ti use i dont want to much flow going into thee fuge but i also dont want to over flow my sump. any ideas?

 

[ClamLubber]

Well, you are asking for a nightmare with any way you would try to go from sump to fuge with both on the floor. If the fuge pump stops and the sump keeps pumping to it you will have a big clean up job. If the sump pump fails then the refuge will empty up to tank and the return will overflow the sump. If you can go vertical, put the refuge higher than the display. Pump from the sump up to the refuge (more head, so bigger pump) and gravity feed from the fuge to the display. The bonus there is pods in the refuge dont take the ride through the pump. Other option, if the space under the tank is tall enough, would be to build a box for the refuge to sit on that would raise it as high as possible under the tank and still have room to get in for maintainence. Drill the side of the fuge for a bulkhead to gravity drain from there down to the sump. Downside of this would be losing some pods exiting the refuge into your skimmer. If you are doing it under the tank though you likely can't raise the sump high enough to flow down to refuge and still have room for the height of the skimmer I assume(?) will be in the sump.

Ronj, the physics are that the water pressure pushing down into the pump offsets the head you get pumping back up. This does assume that pipes are big enough all around to not restrict flow too badly. So even if you are using a siphon overflow you could get a front side pressure boost IF the water column is standing at some level above the pump. Ideally though gravity feeds are done with bigger tubes to maximize flow so that there is not going to be any significant head of water standing in the return pipe especially with the strong pumps used for closed loops. So generally when people talk about there being minimal head to climb in a closed loop they are talking about a drilled tank. There would be about 2-3 inches from the water level in my overflow to the height of the manifold. If you try to do it with a syphon overflow not only would you need multiple syphons to handle the flow, if one or more of the syphons break then you will burn up the pump running it dry. Also syphon boxes generally mix a lot of air with the flow out of the box. The pump is going to chop it up and your display will look like a big skimmer. I have to position the stand pipe in my overflow high enough that the water flowing into the overflow chamber can't send bubbles deep enough to reach the slotted pipe going to the closed loop. This happens a little when the sump pump is on bypass and the water level in overflow falls to the lower limit of where the standpipe is set. So bottom line is, to do true high flow closed loop, you need a drilled tank, but a manifold from sump return can still spread the just processed water around in the tank. The closed loop is just a good way to have more current in the tank than you generally want going to sump without having powerheads hanging on every wall.

 

[ClamLubber]

Opps, missed the part of less flow to refuge than sump. You would accomplish that overhead with a T on the pipe going up to the refuge. A gate valve would restrict flow to the tank from the T forcing the rest up to the refuge. With the under the tank design, the side of the T could go to the refuge and a gate valve would restrict amount of flow dropping straight down into the sump. Still have one pump and everything else is gravity.

 

[speedyrb29]

ah ok i see what your saying i think i might do the fuge above the tank ill put a lil 10 gallon up there. but if i use a 10 gallon glass tank can i drill it? like the bottom of it?