astroboy March 21, 2013 Share March 21, 2013 I need to do a massive water change on a 90 gallon freshwater tank. The RO/DI water is in the basement and the top of the aquarium is maybe 15 feet higher. I have an Eheim 1260, which is listed as having a max head of 12 feet, so I doubt it will pump water from the basement into the aquarium. I also have an Ocean Runner 2500. I was thinking about hooking those up in series, with the output from the first being connected to the input of the second. I'm thinking that if the pressure from the first pump is X, and the second pump is Y, then putting them in series should give a net pressure of something like X+Y. Has anyone ever done something like this? Seems like it should work but I thought I'd ask rather than destroy the impellers or some other unforeseen consequence. Thanks! Mark Link to comment Share on other sites More sharing options...
Neto March 21, 2013 Share March 21, 2013 hmm I am not sure about hooking them up in series, they will probably need to be running at the same speed so you dont force them or overheat them. Also what happends if one stops working? Another option is to run them in parallel? If one gets damaged, the other will still work even though it will have to work harder. Link to comment Share on other sites More sharing options...
jaddc March 21, 2013 Share March 21, 2013 The physics get a bit wonky. But if you had two identical pumps (rated with a head of 10 feet) in series, then the theoretical head would be 20 feet. In practice, inefficiencies would make it about only 15 feet. If they are not identical, then the increased inefficiencies would dramatically reduce any theoretical gain. Is it possible to pump the water with pump A up one floor into a bucket? Inside that bucket is your second pump to move water the rest of the way to the top of the tank. Link to comment Share on other sites More sharing options...
monkiboy March 21, 2013 Share March 21, 2013 (edited) i have a couple iwaki pumps a 55 and 70RLT you can borrow, buy, or use as you wish for a while. they have max head heights of around 28' so i'm sure they'll get the job done. shoot me a PM, if interested. Edited March 21, 2013 by monkiboy Link to comment Share on other sites More sharing options...
Origami March 21, 2013 Share March 21, 2013 I need to do a massive water change on a 90 gallon freshwater tank. The RO/DI water is in the basement and the top of the aquarium is maybe 15 feet higher. I have an Eheim 1260, which is listed as having a max head of 12 feet, so I doubt it will pump water from the basement into the aquarium. I also have an Ocean Runner 2500. I was thinking about hooking those up in series, with the output from the first being connected to the input of the second. I'm thinking that if the pressure from the first pump is X, and the second pump is Y, then putting them in series should give a net pressure of something like X+Y. Has anyone ever done something like this? Seems like it should work but I thought I'd ask rather than destroy the impellers or some other unforeseen consequence. Thanks! Mark Yes, you can do this although, as pointed out, there can be inefficiencies. It's actually one approach to providing protection against a single point of failure in some systems (spreading the return pump failure risk across two units so that there's a very low probability of total loss, even though there's a higher probability of partial loss). Putting them in parallel will not get you additional height, though. Link to comment Share on other sites More sharing options...
astroboy March 21, 2013 Author Share March 21, 2013 i have a couple iwaki pumps a 55 and 70RLT you can borrow, buy, or use as you wish for a while. they have max head heights of around 28' so i'm sure they'll get the job done. shoot me a PM, if interested. Thanks, but this is going to be a one time thing. If hooking the pumps up in series doesn't work I'll just make the kids tote buckets up the stairs. That's why I had them, to support my hobby Link to comment Share on other sites More sharing options...
jaddc March 21, 2013 Share March 21, 2013 Thanks, but this is going to be a one time thing. If hooking the pumps up in series doesn't work I'll just make the kids tote buckets up the stairs. That's why I had them, to support my hobby Link to comment Share on other sites More sharing options...
astroboy March 21, 2013 Author Share March 21, 2013 The physics get a bit wonky. But if you had two identical pumps (rated with a head of 10 feet) in series, then the theoretical head would be 20 feet. In practice, inefficiencies would make it about only 15 feet. If they are not identical, then the increased inefficiencies would dramatically reduce any theoretical gain. Is it possible to pump the water with pump A up one floor into a bucket? Inside that bucket is your second pump to move water the rest of the way to the top of the tank. I'll probably end up doing that. Although, just to see what happens I'll probably hook them up in series first. The pumps aren't identical of course, but I imagine the impeller rotation rates are the same, or multiples of 60Hz, so things might work. It will be an interesting way to spend a Saturday evening. Link to comment Share on other sites More sharing options...
jaddc March 21, 2013 Share March 21, 2013 Cool -- I'd be interested in what happens if you care to share your experience. Link to comment Share on other sites More sharing options...
Origami March 21, 2013 Share March 21, 2013 I was going to do a similar experience linking two maxijets to see what the impact to max head height was. I've built an adapter to take the output from one and push it into to the input of a second. I just need (want) warmer weather and an hour to try it out. Ultimately, the idea was to see if I could put two maxijets in series and have the tandem arrangement perform as an emergency backup to, say, a Mag-3 or a Mag-5. Link to comment Share on other sites More sharing options...
Der ABT March 21, 2013 Share March 21, 2013 i would think the bigger of the pumps furthest away, aka waters source on the floor and then plumbing in the weaker of the pumps up near the ceiling would do the trick but i could be wrong....let the big pump do the initial work and the pump mounted up near the ceiling finish the job. a bigger pump would be much easier and cheaper down the road i would think energy, maint, etc wise piece of mind Link to comment Share on other sites More sharing options...
Integral9 March 21, 2013 Share March 21, 2013 Thanks, but this is going to be a one time thing. If hooking the pumps up in series doesn't work I'll just make the kids tote buckets up the stairs. That's why I had them, to support my hobby Ditto. Got 1 in training already and one more on deck. Is it possible to pump the water with pump A up one floor into a bucket? Inside that bucket is your second pump to move water the rest of the way to the top of the tank. This is what I would do. You could also attach a float switch to the bucket and wire it down to the first pump so it automatically comes on when it needs to fill the bucket. You might want a two way float switch though and put the 2nd float switch in the primary reservoir, so the first pump comes one when it needs to fill the bucket upstairs, but also won't come on if the primary reservoir is empty. Link to comment Share on other sites More sharing options...
zygote2k March 23, 2013 Share March 23, 2013 anyone remember the Simpsons episode where Bart and Milhouse break into the police station? they find 100 bullhorns and link them together, Bart turns it on and says, "testing" and creates a sonic boom. Link to comment Share on other sites More sharing options...
astroboy March 24, 2013 Author Share March 24, 2013 Here are the results from the experiment: The first pump was the Eheim 1260, which fed into the Ocean Runner 2500 through a three foot hose. As it happened, the Eheim all by itself had enough power to pump water from the basement into the aquarium, when the 2500 was turned off. As soon as I turned on the 2500, the flow volume dropped dramatically, like, to 10% of what it was with the 2500 turned off. I tried it three or four times, same results each time. I would have thought there would have been at least a small improvement.... Apparently, there's some sort of back pressure thing going on. Perhaps the forced input from the Eheim made the impeller on the 2500 spin backwards. What I'm thinking is that with these pumps the impellers are going to spin at a certain rate, X, which is probably some multiple of 60 Hz. If there's a big head or some other impedance, I'm guessing the impellers still spin at the same rate, but the flow becomes sort of chaotic. Rather than all the water moving out of the pump, perhaps it just sort of sloshes around. After all, you can put your thumb over the output from a pump and it seems to still spin at the same rate. Perhaps someone out there knows what actually happens. Anyway, if the impeller is set to spin at a certain rate, when water is forced into it, the impeller might act as a brake, since its only going to spin at X revolutions per second, no matter what. Possibly, results would be different with the weaker pump feeding into the stronger pump. I'll set that up in a few days and see what happens. Link to comment Share on other sites More sharing options...
Origami March 24, 2013 Share March 24, 2013 Volute of the second pump adds back pressure. It may have been more than the pump could add. Interesting result still. (Sent from my phone) Link to comment Share on other sites More sharing options...
astroboy March 24, 2013 Author Share March 24, 2013 Volute of the second pump adds back pressure. It may have been more than the pump could add. Interesting result still. (Sent from my phone) I might not have been clear on this: I had both pumps hooked up in series. When the 2500 was off, the Eheim pumped water like a champ. When the 2500 was on, and the Eheim was also on, the volume of flow dropped greatly. The second pump impeded flow very little when it was turned off. Link to comment Share on other sites More sharing options...
Integral9 March 25, 2013 Share March 25, 2013 This. .... the impeller is set to spin at a certain rate, when water is forced into it, the impeller might act as a brake, since its only going to spin at X revolutions per second, no matter what. With similar pumps, you would probably achieve the expected result of doubling the head. Link to comment Share on other sites More sharing options...
jaddc March 25, 2013 Share March 25, 2013 What happens when you reverse the order? Link to comment Share on other sites More sharing options...
Tracy G March 25, 2013 Share March 25, 2013 This. With similar pumps, you would probably achieve the expected result of doubling the head. I don't think it would double. It would still only spin the same speed the best it would do is maintain. Just a guess though Link to comment Share on other sites More sharing options...
jaddc March 25, 2013 Share March 25, 2013 I don't think it would double. It would still only spin the same speed the best it would do is maintain. Just a guess though Based on what Mark observed, I'd hypothesize that the slow pump was applying a drag force which was large enough to reduce the water flow head. Link to comment Share on other sites More sharing options...
Integral9 March 25, 2013 Share March 25, 2013 I don't think it would double. It would still only spin the same speed the best it would do is maintain. Just a guess though No, not quite. But it would be close. Two identical pumps aren't going to have the pushing / shoving match that 2 differing pumps will have, which is what I think the problem is. Which is probably the result of the differing impeller designs of the two brands. eg: If you have 2 people, one standing on the shoulders of the other, they can lift something twice as high as just one guy. If you have two guys standing on the same level, they can lift twice as much, but no higher than only 1 guy can lift. Link to comment Share on other sites More sharing options...
mr.x-ray March 25, 2013 Share March 25, 2013 If you have two equal pumps usually you would get roughly half the value of a second pump and quarter of a third and so on. Say 10 foot head each. 2 Pumps at the same elevation would get you 15ft and 3 would get you 17.5... Magnetic drive pumps don't have enough suction power (sucking from a lower pump) to make a difference. They are designed mainly to push fluids. Link to comment Share on other sites More sharing options...
zygote2k March 25, 2013 Share March 25, 2013 testing... Link to comment Share on other sites More sharing options...
Integral9 March 26, 2013 Share March 26, 2013 2 Pumps at the same elevation would get you 15ft and 3 would get you 17.5... Why would you put both pumps at the same level? I don't think that would be optimal as you wouldn't be maximizing the head from each pump. http://www.engineeringtoolbox.com/pumps-parallel-serial-d_636.html Link to comment Share on other sites More sharing options...
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