mag 12 outlet diameter

snazlord · 10-02-2003, 12:18 PM

mag 12 comes with 3/4" return line, but i THINK the instructions that came with it (which i've since lost) said to use 1.5" for maximal flow rate.

question: can anyone confirm this, and/or does anyone know what the best diameter outflow to use on a mag 12 is? I know it's a balance between the additional weight of the water column with larger diameters versus the additional friction/pressure with smaller diameters, but can't remember for sure what the best diameter would be.

tdwyatt · 10-02-2003, 01:05 PM

flow at 1.5" is much higher due to decreased frictional loss (really a LOT). Head losses are not affected per se by pipe diameter, only in terms of the losses due to friction of a smaller pipe. (Ask Galileo whijch falls faster, feathers or cannon shot?

)

MyReef · 10-03-2003, 09:18 AM

For best results Danner recommends going to the next size diameter tube/pipe when plumbing their pumps...so the MAG 12 would be best using a 1" line....

snazlord · 10-03-2003, 03:33 PM

well, there's one vote for 1" and one for 1.5".

FWIW, i'm going to use 1.5" (the 1.5" goes straight up about 3 feet, then splits (1.5" Y ) into two 3/4" conduits (one for the return line and one to the skimmer)

Casey · 10-03-2003, 04:04 PM

1.5 all the way dude

thefatman · 10-03-2003, 08:28 PM

i had the same question when i installed my mag18 for my cls, and just didnt quite understand the concept.. but now i do

of course, it's too late to yank the cls hoses now, or i'll have a nice flood on my hands

however, i have a genx4100 as my return pump, running through 3/4" flexible tubing. would i get better flow from it if it were on a 1" hose instead?

Casey · 10-03-2003, 09:08 PM

Quote:

Originally posted by thefatman
i had the same question when i installed my mag18 for my cls, and just didnt quite understand the concept.. but now i do

of course, it's too late to yank the cls hoses now, or i'll have a nice flood on my hands

however, i have a genx4100 as my return pump, running through 3/4" flexible tubing. would i get better flow from it if it were on a 1" hose instead?

Yes

Joel · 10-03-2003, 10:29 PM

I didn't understand the concept either until I got the new tank with 2 3/4" returns. It was getting late so I hooked up only 1 1" drain (had to drill the sump cover for an additional 1" drain) but both returns and promptly overflowed my 135. I am using the same Mag 9.5 that I was in the 90 and never had an overflow problem. But I only had 1 return. That immediately told me that I had a lot more return volume loss in the old tank than I thought. I guess any future tanks I set up will always have oversized pipe.

MyReef · 10-04-2003, 01:23 AM

If you want less friction loss use the 1.5", but you will get less velocity. IF you want good velocity use the 1". FWIW, I have 3 AMpmaster 3000's and 2 are plumbed with 1 1/2" all the way to the outlet but I reduce to 1" the other uses all 1 1/2" included the outlet....I get much better flow with the 1" line....

If you are splitting the pump outlets also, you will reduce the flow to almost nothing with 2 or more outlets on 1 1/2" line....

Been there done that changed the plumbing...JME