Back pressure

Spiffyguy · 11/23/2006, 10:23 AM

How can you tell if you are getting back pressure on a pump? I am setting up some plumbing and using a MJ900. I am concerned a T I am using is going ot cause back pressure. I really won't know intil I try but I wanted to know what the signs were. I know that MJ are not good pressure pumps either. Don't want to burn it up.

Thanks

Avi · 11/23/2006, 10:39 AM

Well, it's hard to say exactly what would happen, but most likely, in a simple application, if the pump isn't strong enough, you just won't get the result you want. What is the plumbing application?

Spiffyguy · 11/23/2006, 10:45 AM

I am setting up a mj900 as a return pump for an in tank sump system. I have a bunch of 1/2" CPVC pipe that i am going to use. I could not find a Y to split it off to two locations, so I am going to use a T. I will ahve some hose to connect the pump to the T. I am just concerned the water will either creat back pressure of cavetate (sp?) and create air bubbles.

Spiffyguy · 11/23/2006, 10:48 AM

here is how I plan ot use it.

http://reefcentral.com/forums/showthread.php?s=&threadid=976398

2NDTIME AROUND · 11/23/2006, 12:24 PM

You will alwas get some head presure on the pump. You just have to size the pump with that in consideration.

Agu · 11/23/2006, 12:31 PM

Quote:

Originally posted by Spiffyguy
here is how I plan ot use it.

http://reefcentral.com/forums/showthread.php?s=&threadid=976398

Link doesn't work.

I did something similar with a 160 gph powerhead and it works just fine, distance from the pump to T is about 6"..........

hth,

Spiffyguy · 11/23/2006, 12:34 PM

hmm odd try this one. http://reefcentral.com/forums/showth...hreadid=976398

I am not sure I will be able to get 6 inches but that is similar to what I will be doing. one side will have a longer travel though, about 10 inches.

Agu · 11/23/2006, 12:41 PM

Found the thread, here's how my internal overflow looks,

It's only a 5.5 so it was tight. Your plan should work fine with the MJ900. My one outlet is also longer with an elbow too but that doesn't seem to affect flow from that outlet noticeably. I would highly recommend the adjustable flare nozzles. Once you get it set up if your outlet is too close to the surface it'll create a whirlpool effect and suck air there.

Spiffyguy · 11/23/2006, 04:43 PM

i plan on having 2 Mj900s with two outlets each. on set will be a bit above the sand and the 2nd set will be mid to upper tank with Hydors on them to stir up the flow. All outlets will have a couple of loc line if I can swing it so I can direct the flow if need me. I like the idea of flare nozzles on the bottom ones, that way if the flow is slightly dimished the flare will pick it up. I also plan to do one Mj900 with the mod on it right in the center shooting down the length.

syrinx · 11/23/2006, 08:56 PM

A cheap and dirty- but not inaccurate way to judge head is add 1 foot for every 90 turn or reduction. That would put the head pressure on your piece at 3 ft or so- as one of the restrictiors would be on the pump anyway.

Spiffyguy · 11/23/2006, 09:27 PM

would having the T free it up though. being as ther eis more than one outlet.

syrinx · 11/23/2006, 09:33 PM

good question- it does increase flow, but also is a redirection. The fact you seem to be jumping from smaller soft to larger pvc would no doubt help also. I would have no issues with using the pump this way. When you are doing more standard length plumbing, or making a skimmer- that is the opportune time to remember the 90=1foot ratio.

Spiffyguy · 11/23/2006, 09:38 PM

lol ok. I will run with it and see if I have any issues. I will keep an eye out for bubbles. I guess that can be a sign of cavetating.

11/23/2006, 10:23 AM	#1
Spiffyguy Registered Member Join Date: Aug 2004 Location: St Charles, Mo Posts: 1,633	Back pressure How can you tell if you are getting back pressure on a pump? I am setting up some plumbing and using a MJ900. I am concerned a T I am using is going ot cause back pressure. I really won't know intil I try but I wanted to know what the signs were. I know that MJ are not good pressure pumps either. Don't want to burn it up. Thanks __________________ Spiffyguy Ain't life spiffy!! Click the little red house to see my fish tank. "The cheese stands alone." Current Tank Info: 55 with in tank sump and TBS rock, Aquactinics TX5, Remora HOB oh my. 10 gallon AGA with custom overflow and Aquaclear HOB, Black sand rubble zone.

11/23/2006, 10:39 AM	#2
Avi Premium Member Join Date: Feb 2001 Location: Westchester County, NY Posts: 7,327	Well, it's hard to say exactly what would happen, but most likely, in a simple application, if the pump isn't strong enough, you just won't get the result you want. What is the plumbing application? __________________ I'd keep the whole ocean if my den were big enough Current Tank Info: 120 gallon reef with 210 lbs. of live rock, Aqua-C EV180 Skimmer, Aquactinic double 250W MH with blue plus t5 support; 58 gallon freshwater planted tank using CO2 and T5s; 30-gallon cube with a few fancy goldfish; and a 110 gallon FOWLR

11/23/2006, 10:45 AM	#3
Spiffyguy Registered Member Join Date: Aug 2004 Location: St Charles, Mo Posts: 1,633	I am setting up a mj900 as a return pump for an in tank sump system. I have a bunch of 1/2" CPVC pipe that i am going to use. I could not find a Y to split it off to two locations, so I am going to use a T. I will ahve some hose to connect the pump to the T. I am just concerned the water will either creat back pressure of cavetate (sp?) and create air bubbles. __________________ Spiffyguy Ain't life spiffy!! Click the little red house to see my fish tank. "The cheese stands alone." Current Tank Info: 55 with in tank sump and TBS rock, Aquactinics TX5, Remora HOB oh my. 10 gallon AGA with custom overflow and Aquaclear HOB, Black sand rubble zone.

11/23/2006, 10:48 AM	#4
Spiffyguy Registered Member Join Date: Aug 2004 Location: St Charles, Mo Posts: 1,633	here is how I plan ot use it. http://reefcentral.com/forums/showthread.php?s=&threadid=976398 __________________ Spiffyguy Ain't life spiffy!! Click the little red house to see my fish tank. "The cheese stands alone." Current Tank Info: 55 with in tank sump and TBS rock, Aquactinics TX5, Remora HOB oh my. 10 gallon AGA with custom overflow and Aquaclear HOB, Black sand rubble zone.

11/23/2006, 12:24 PM	#5
2NDTIME AROUND Registered Member Join Date: Oct 2006 Location: HOMOSASSA FL. Posts: 97	You will alwas get some head presure on the pump. You just have to size the pump with that in consideration. __________________ Just another rocky shoal your ship must navigate on the sea of life. Current Tank Info: 120 galon drilled tank with 30 gal sum, refgium, nautilus te skimmer driven by mag7, mag12 return pump. 260 watts pc lighting

11/23/2006, 12:34 PM	#7
Spiffyguy Registered Member Join Date: Aug 2004 Location: St Charles, Mo Posts: 1,633	hmm odd try this one. http://reefcentral.com/forums/showth...hreadid=976398 I am not sure I will be able to get 6 inches but that is similar to what I will be doing. one side will have a longer travel though, about 10 inches. __________________ Spiffyguy Ain't life spiffy!! Click the little red house to see my fish tank. "The cheese stands alone." Current Tank Info: 55 with in tank sump and TBS rock, Aquactinics TX5, Remora HOB oh my. 10 gallon AGA with custom overflow and Aquaclear HOB, Black sand rubble zone.

11/23/2006, 12:41 PM	#8
Agu Registered Member Join Date: Oct 1999 Location: Sarasota, Florida Posts: 30,279	Found the thread, here's how my internal overflow looks, It's only a 5.5 so it was tight. Your plan should work fine with the MJ900. My one outlet is also longer with an elbow too but that doesn't seem to affect flow from that outlet noticeably. I would highly recommend the adjustable flare nozzles. Once you get it set up if your outlet is too close to the surface it'll create a whirlpool effect and suck air there. __________________ Less technology , more biology . Current Tank Info: 30 gallon half cube and 5.5, both reef tanks

11/23/2006, 04:43 PM	#9
Spiffyguy Registered Member Join Date: Aug 2004 Location: St Charles, Mo Posts: 1,633	i plan on having 2 Mj900s with two outlets each. on set will be a bit above the sand and the 2nd set will be mid to upper tank with Hydors on them to stir up the flow. All outlets will have a couple of loc line if I can swing it so I can direct the flow if need me. I like the idea of flare nozzles on the bottom ones, that way if the flow is slightly dimished the flare will pick it up. I also plan to do one Mj900 with the mod on it right in the center shooting down the length. __________________ Spiffyguy Ain't life spiffy!! Click the little red house to see my fish tank. "The cheese stands alone." Current Tank Info: 55 with in tank sump and TBS rock, Aquactinics TX5, Remora HOB oh my. 10 gallon AGA with custom overflow and Aquaclear HOB, Black sand rubble zone.

11/23/2006, 08:56 PM	#10
syrinx Registered Member Join Date: Jul 2006 Location: champaign Posts: 3,160	A cheap and dirty- but not inaccurate way to judge head is add 1 foot for every 90 turn or reduction. That would put the head pressure on your piece at 3 ft or so- as one of the restrictiors would be on the pump anyway. __________________ My views are based on 49years as an aquarist, 25 years as a pro reef consultant, 10 years of owning a LFS, and the results of thousands of customers tanks. But I am always learning.

11/23/2006, 09:27 PM	#11
Spiffyguy Registered Member Join Date: Aug 2004 Location: St Charles, Mo Posts: 1,633	would having the T free it up though. being as ther eis more than one outlet. __________________ Spiffyguy Ain't life spiffy!! Click the little red house to see my fish tank. "The cheese stands alone." Current Tank Info: 55 with in tank sump and TBS rock, Aquactinics TX5, Remora HOB oh my. 10 gallon AGA with custom overflow and Aquaclear HOB, Black sand rubble zone.

11/23/2006, 09:33 PM	#12
syrinx Registered Member Join Date: Jul 2006 Location: champaign Posts: 3,160	good question- it does increase flow, but also is a redirection. The fact you seem to be jumping from smaller soft to larger pvc would no doubt help also. I would have no issues with using the pump this way. When you are doing more standard length plumbing, or making a skimmer- that is the opportune time to remember the 90=1foot ratio. __________________ My views are based on 49years as an aquarist, 25 years as a pro reef consultant, 10 years of owning a LFS, and the results of thousands of customers tanks. But I am always learning.

11/23/2006, 09:38 PM	#13
Spiffyguy Registered Member Join Date: Aug 2004 Location: St Charles, Mo Posts: 1,633	lol ok. I will run with it and see if I have any issues. I will keep an eye out for bubbles. I guess that can be a sign of cavetating. __________________ Spiffyguy Ain't life spiffy!! Click the little red house to see my fish tank. "The cheese stands alone." Current Tank Info: 55 with in tank sump and TBS rock, Aquactinics TX5, Remora HOB oh my. 10 gallon AGA with custom overflow and Aquaclear HOB, Black sand rubble zone.