Pump and over flow - flow rates

[IPWitan]

I have a mag drive 5 (480 gal at 1 ft) as a return pump. The pump is returning water to the tank upwards, with 4-5 feet of head, traveling in 1/2 in pvc and plastic tubing. The overflow is a standard overflow, with 3/4 inch hole to the sump, using 3/4 hose, with a standard u shaped tube from the in tank prefilter box to the overflow chamber. Is this going to flood at full power?

Info suggests overflow will carry 300 gal, and pump is about that at 4-5 feet (guessing). Should I get a bigger overflow?

example of over flow: http://www.fosterandsmithaquatics.com/product/prod_display.cfm?c=3578+3579+3587+18358&pcatid=18358

info on pump: http://www.marineandreef.com/Pondmaster_Mag_Drive_Pumps_Power_Head_Powerhead_s/391.htm


I assume many have a similar set up and am hoping someone can chime in before I pump it all up. I am placing an old pump with the mag 5, and don't know whether it is to powerful.

Thanks in advance.

David

 

[metalfab]

Just from my research ( just finished plumbing my first sump), it is wise to put a ball valve and a T fitting so you can restrict your flow and the restricted flow will T back to the sump with no strain on your pump. Cheap materials for complete flow control.

 

[naturebatslast]

IME, you could probably run it wide open without trouble, but the ball valve will let you feather the output.

 

[fire911]

a single U tube overflow could be anywhere from 300 gph to i think 800 gph. If your going to put a T back to your sump I would use a PVC gate valve. It is much easier to "fine tune".

 

[JayM]

Basically, you are asking a 3/4" pipe which is a gravity drain to equal out a 1/2" supply. Even with the lost flow due to head loss from your 4-5' of head, it is probably not a good idea to run that pump without the T and gate valves suggested above. Then you are going to want to check your drain pipes for algae, biofilm, etc and adjust your flow (probably weekly)

last question....do you have a float valve pump shutoff in your display in the event that the overflow loses siphon? Having that mag5 pump all that water into your tank would make a very unpleasant flood.

 

[delta]

Use this to estimate your pump flow to the tank
http://reefcentral.com/index.php/head-loss-calculator

Then this t estimate your overflow capacity.
http://reefcentral.com/index.php/drainoverflow-size-calc

With a HOB overflow you need to keep the flow up, meaning if you under drive the overflow box it gets air pockets and the siphon breaks. Considering mag pump are very inconsistent with output. You are going to want to over drive the overflow and scale it back with a valve.

IMHO for 90g I would go with a bigger overflow/more flow.

 

[IPWitan]

Thank you all.

Yes, I do have a t and ball value after the pump but before the display, which feeds back into the sump.

From what I have read, it seems like I COULD do this wide open, but need a auto shut off in the event something happens, and it would be wise to get a bigger overflow box.

I think I will invest in some auto shut offs. I could use one on my refugium too, just in case that hole gets clogged...

Thanks for the help.

David

 

[IPWitan]

Jay M - do you have a link for the type of float valve pump shutoff you would recommend? The only ones I see are big and for RO topoff systems. I didn't see anything that would fit in a display tank at the 4 websites I investigated.

David

 

[metalfab]

Ipwita, what kind of overflow box do you have. I have the life reef 600gph, it is suposed to be very reliable, but I also would be interested in this pump shut off switch for backup.

 

[Jennifer]

You could build something like this to shut the pump off in case the overflow loses siphon.

I built this one a while back for a member here, He sold it to Miller. Not sure if he still has it or not. It is probably floating around the club somewhere.

I have a web page with the parts list but I never got around to drawing up the schematic. It is just a simple relay circuit.

My web page

 

[metalfab]

Impressive diy projects you've done Jennifer. This one looks to be simple enough for me to attempt. One question, is there also a float switch in the sump to get that "yoyo"?
Do you build these for customers?

 

[wcole]

I tried to use the pump flow calculator "Delta" suggested in a prior post. However, I could not find the "Calculate" button. Where do I look? I did notice that the calculater had 3/4" as the minimum line size.

I am now tackling a low pump flow problem and when using 1/2" inch lines, and would appreciate any suggestions to help me increase the flow rate through the refugium. My situation, and what I am doing, is described below. My preliminary conclusion is that I would not worry about too much flow with a 1/2" line, rather not enough. My preliminary conclusion is that 3/4" lines, at a minimum, are required.

My flow is from a 30 gallon refugium to a 90 gallon display tank with a 3 foot vertical lift (waterline to waterline). Originally I used a 1/2" line with a Mag 3 pump. Flow was very small. Switched to a Mag 7 pump and measured flow rate at 15 gph (that's fifteen).

I have a U fitting in the pump return line to prevent draindown when the pump stops (rather than a check valve). Originally, I had three 1/2" CPVC street elbows with an internal diameter of 3/8". Changed these three fittings to 1/2" PVC (with an internal diameter of 1/2") and the flow increased to 40 gph.

I still have several 1/2" hose barbs in the line, with an internal diameter of 3/8" and 2 lengths of 1/2" tubing. I plan on changing the line from the pump to the bulkhead fitting to 3/4" and hope this solves the problem. I will still have a section of 1/2 inch line between the bulkhead fitting and the flow nozzle into the tank. This will be difficult to upgrade and I hope I don't have to.

Any suggestions? Do I have 2 bad pumps?

 

[Jennifer]

1/2 line for the return on a mag 5 is just fine for flow.
I would go with 1 inch drain lines min from the overflow box.

15 gph sounds all wrong either your pumps are bad or you really mean 15gpm and forgot to time it by 60 for the gallons per hour.

Impressive diy projects you've done Jennifer. This one looks to be simple enough for me to attempt. One question, is there also a float switch in the sump to get that "yoyo"?
Do you build these for customers?

Thanks
The relay used is a non latching style , that just means that you do not have to reset it.
If the float switch at the top of the DT is triggered, the return pump will shut off. This will cause some water to siphon back through the return lines to the sump. Once the water levels is low enough again the float switch will automatically turn the pump back on.
This will just repeat over and over until you are able to clear the drain lines or restart the siphon in a HOB overflow.

Of course the amount of water draining back to the sump will be determined by how your return lines are plumbed to the tank.

 

[wcole]

Jennifer:

Thanks for questioning me. but there was no mistake. It took 30 seconds to collect a measuring cup (2 cup size) of water.

Do I have bad pumps?

 

[IPWitan]

The link below says your mag 3 should have about 335 gal per hour at 3 feet.

http://www.marineandreef.com/Articles.asp?ID=124

Thus, it would seem your pump is bad. Also, I stuck my mag5 in the bath tub to make sure it worked, and it shot water everywhere, including hitting the ceiling 7 feet up. Thus, I am not worried about having too little pressure. The standard fitting on it is 1/2, thus, I am not concerned about that either.

I am concerned, however, about only have 3/4 inch return pipe on the overflow.

Anyone have an extra 1 inch overflow box for sale? Didn't see one in the forum.

Jennifer, your device looks like exactly what I need. Unfortunately, I am not electrically inclined, and replacing a ballast is about as complicated as I am comfortable. I haven't found something like that for sale, either. Bummer.

David

 

[Sportsmann]

Hi
I will on Saterday when I pick up me tank.
I just bought cherokee 110 drilled so my 90 undrilled will be posted along with the overflow and dosing pump. Cheap money or corals...
PM me thanks

 

[Jennifer]

Jennifer:

Thanks for questioning me. but there was no mistake. It took 30 seconds to collect a measuring cup (2 cup size) of water.

Do I have bad pumps?

Welcome,

I would say that yea, you may just have a pump issue there.
2 cups in 30 sec is way slow.

If I was not in the middle of a tank build I would prob be able to build a few of these for you guys.
I work for frags, lol.
If when I am done with my tank build and you are still interested let me know.