bulkhead flow ratings

the Undone guy · #1 07/19/2005, 09:15 AM

Is there a website anywhere that lists flow ratings for bulkhead sizes?

I ordered my new tank to have a hole that will fit a 1.5" bulkhead like everyone recommended; but now i'm seriously thinking of getting a new pump before I get everything setup. Jeff mentioned yesterday that he believed a 1.5" bulkhead was rated for a mag 12 (1200GPH), but I'm not sure if he was certain or not? =)

drfostersmith.com has mag-drive pumps 15% off right now so a mag12 is $90 and a mag18 is $101. I wouldnt mind spending the extra $10 for the 18 if it would help my system. So does TOO much GPH = bad for the system?

opihi · #2 07/19/2005, 12:58 PM

i wouldn't say it's bad for the system, and you can always put a couple of bulkheads to redirect unwanted flow back to your sump.

another thing to consider is heat transfer. i've never used a mag 18, but my old mag 12 used to get kinda hot.

opihi · #3 07/19/2005, 01:03 PM

flow rate post in DIY forum:
http://archive.reefcentral.com/forum...ight=flow+rate

make sure you read the entire thread, as the ninital estimates are clearly high.

the Undone guy · #4 07/19/2005, 01:31 PM

thanks jeff, i know im wanting to go higher flow so i figure a bigger pump would do the job (especially since they're on sale!). My mag 7 gets decently warm but the water cools it to a good temp, and since the water is flowing so much it doesnt heat up the tank to anything above 80 degrees. I dont want to over-do it, but then again if there is potential for more flow why not?

In that post they said the 1.5" bulkhead ranges from 1200-1600 GPH, is that fluxuation due to different pipe configurations? Like T-s and Elbows lowering the max flow? So if it was going straight down you could potentially get up to 1600GPH?

And you want to match the up and the down flow correct? I mean if you have say 1400GPH flowing down into your sump, you want 1400GPH flowing into your tank right?

opihi · #5 07/19/2005, 02:02 PM

i suppose potentially you could get 1600 GPH if you minimize bends in the drain. i'm not going to make like i understand fluid dynamics though, so i would just try to shoot for ~1400 GPH and call it a day.

just build a bypass into your plumbing so if the flow is too strong, you can adjust it w/ ball valves and redirect extra flow back into your sump.

also, i'm not sure how a mag18 handles head pressure, so you should try to calculate your head pressure first, then find the pump that best delivers w/ the HP your plumbing will have.

opihi · #6 07/19/2005, 02:04 PM

Quote:

Originally posted by opihi
i wouldn't say it's bad for the system, and you can always put a couple of bulkheads to redirect unwanted flow back to your sump.

another thing to consider is heat transfer. i've never used a mag 18, but my old mag 12 used to get kinda hot.

i just reread that and i meant to say ballvalves, not bulkheads.

LVfishguy · #7 07/20/2005, 02:03 AM

Just a not Magnetic drive pumps are really bad on keeping hteir head pressure. I don't know the acutal specs but a mag18 will get nowhere near 1800 GPH. I would go with the bigger pump and redirect the flow like Jeff had said.

Desert Fish · #8 07/20/2005, 03:09 AM

12-1400gph is about all a 1.5" bulkhead will handle. An External pump would be better since bigger pumps produce significant head and this eliminates the problem to a large extent. Dolphin and Gen-X make good int/ext pumps that will do the job and Gen-X especially has proven very reliable. Use a pump that will pump more than you need and use a globe or gate valve on the pump discharge to fine tune to your overflow capacity. This eliminates piping back to the sump. Use multiple outlets on the tank return to allow puting current where you want it.
BTW many reefs now run 20 to 40x tank volume so your only constrain it what your surface skimmer can handle

mike bracken · #9 07/20/2005, 11:19 PM

I have a dolphin 2100 plumbed through 1.5" pipe. Its 2100 gph at 4' of head, low heat transfer great pumps.

Desert Fish · #10 07/21/2005, 12:43 AM

Just to be clear - I believe you are talking about a1.5" pump discharge line not a tank overflow.
You are right though, Dolphin Ampmasters are very good long lived pumps - use 6 of them myself.

the Undone guy · #11 07/21/2005, 01:05 AM

I am speaking of a 1.5" bulkhead used in the bottom of a tank overflow box....

the Undone guy · #12 07/21/2005, 10:53 AM

ok now you guys have me confused =) From what I understand Chris is saying that MAG drives lose their headpressure very easily and desert fish recommends going with a dolphin or a gen-x int/ext pump.

now jeff said to shoot for 1400GPH which i think would be about right when you take into account head pressure and what not.

First question, are the Gen-X pumps such as this one: http://www.marinedepot.com/md_viewIt...product=PI1117 internal? I really dont have the plumbing or room to handle an external pump otherwise i'd be all for it. And the only reason I ask because it says nothing about being an internal pump.

So I think my real internal debate is between the Mak4 Gen-X pump, and a MAG. I tried the RC Head Loss calculator http://www.reefcentral.com/calc/hlc2.php and plugged in some ROUGH estimates of what my plumbing might have with both pumps and the MAG18 go 1310GHP while the Mak4 only rolled in at 1064GPH. Now im not sure if that has to do with the rating of 1800 to 1190. But what I did notice was that the MAG lost 4.56 feet of head pressure while the Gen-X only lost 4.37. Now that's such a tiny amount im not sure if it matters....

Im just hoping you guys can help me sort out my confusion

and is that head pressure loss calulator even acurate?

opihi · #13 07/21/2005, 12:22 PM

Bobby, the title on the MD link you sent reads "Gen-X PCX40 1190 GPH External Water Pump"

they can't be run in your sump.

another thing for you to consider is the noise that the pump will make, considering this new tank will go in your bedroom. i hear that Gen-x pumps are similar to Iwakis. if that's true, there's no way i'd put one in my bedroom. My iwaki's pretty quiet, but it does sound similar to a refridgerator, or a pretty quiet air conditioner... it would bug the heck out of me.

did you try plugging the Mag24 into the calculator? i don't know how accurate it is, but i'd imagine it's pretty reliable.

the Undone guy · #14 07/21/2005, 08:08 PM

yea I think i'm going to with a MAG24. One thing i forgot to take into concideration is the output pipe diameter. The actual outlet on the MAG24 is 1" compared to 3/4" on the 12 and 18. And by adjusting what diameter pvc to use for the return i can adjust the GPH to just over 1400GPH which is right where i want to be.

What exactly happens if you have more flow than your Bulkhead can handle, just a simple overflow? I'm thinking of keeping the return plumbing VERY simple so I can adjust PVC diameter without having to redo a complicated return line. And if im doing all of these test under fresh water conditions, will it change enough to notice under salt water conditions? (head pressure etc etc)

What do you think?

Desert Fish · #15 07/21/2005, 08:39 PM

The Gen-X models GX-6000 (1200gph@4.5ft) and the GX-8500 (1850gph@4.5ft) are submersible and I recommend above Dolphin aquasea because of stronger impeller design - the only part that can break.
The Dolphin ampmasters (external)are just about the best presently on the market - low speed (1750 rpm), high volume,low running cost, very low heat transfer, low noise - much quieter than Iwaki and cheaper. The Gen-x externals are high speed pumps (3000rpm) and have increased friction heat and noise for that reason.
Don't try to run at max capacity, especially on the overflow - capacity gets shot to hell ( and your floor) if a turbo gets adventurous.

opihi · #16 07/21/2005, 09:38 PM

FWIW, you can upsize your plumbing by using reducer fittings to connect it to your pump. i'm using 1.5" plumbing with 1" I/Os on an Iwaki 55

>>What exactly happens if you have more flow than your Bulkhead can handle...

wet floors.

i liked ampmasters for all the same reasons, but they have one major drawback-- the leaky seals. maybe you'll be one of the lucky ones who doesn't get one... i wasn't.

the Undone guy · #17 07/22/2005, 12:21 AM

so neither of you think the mag24 would be a good idea? =P

Jeff you are completely right about me needing a quiet pump, currently i'm perfectly content with my Mag7 because it's quiet, stays cool, and keeps working like a charm. (knock on some wood) Its difficult to find the GenX pumps...i wouldnt mind finding a more reliable place to buy than a place i've never heard of if i were to get a GenX pump.

Right now Desert Fish has me torn between a Gen-X8500 and a Mag24....arg!

Desert Fish · #18 07/22/2005, 12:46 AM

Jeff- Doplphin addressed that issue in July last year by changing the seal and coating the shaft - but you have to order one specifically for high abrasive marine reef use.
If it helps - the 8500 is available for 110.00 complete

LVfishguy · #19 07/22/2005, 08:19 AM

Well bobby, I have never acutally used a GenX pump but I can tell you that Mag24's are pretty noisey. I don't think that I would use that pump in my bed room...

Desert Fish · #20 07/22/2005, 02:18 PM

Bobby, Tried a PM box full. try again later. Yes I have three running oldest 2 years. Quiet, reliable. I'll be in LA next Monday and could pick up one if you want

the Undone guy · #21 07/22/2005, 03:19 PM

Quote:

Originally posted by Desert Fish
Bobby, Tried a PM box full. try again later. Yes I have three running oldest 2 years. Quiet, reliable. I'll be in LA next Monday and could pick up one if you want

had no idea that your PM box had a limit

shoot me over some prices, i saw those ones online for about $90 not sure if they're the same.

Desert Fish · #22 07/22/2005, 04:57 PM

I can get it to you Wednesday for 105.00 - gotto charge tax.
Same pump as shown in your custom aquatics address.
They are wrong about the pump- it operates perfectly both as a submersible and as an external.
Let me know if you want any livestock or other drygoods as well.

Gary

Desert Fish · #23 07/22/2005, 04:58 PM

Sorry - that was supposed to be a pm

opihi · #24 07/24/2005, 01:42 AM

Quote:

Originally posted by Desert Fish
Jeff- Doplphin addressed that issue in July last year by changing the seal and coating the shaft - but you have to order one specifically for high abrasive marine reef use.

i guess that's good news... i really liked the pump until it started leaking... i got replacement seals that were supposed to have taken care of it in 2003. so i was just really disappointed when those started leaking too.

how expensive are the new seals?

Desert Fish · #25 07/25/2005, 04:57 PM

Jeff - send it to Dolphin Pumps in FLA. $75.00 for seal & return shipping. Labor covered by 9 year warrenty.