Return pump and plumbing question

[gregghia]

#1 Is a Mag 12 too much for a 75 gal? I bought this and figured more push is better than less. The return plumbing does not have to go far to get back to DT... maybe 3 feet.
#2 Are 2 90 degree elbows OK in teh return plumbing or should I avoid 90? Seems like its gonna be easier to plumb but I feel like pressure will be lost....
Thanks

 

[frankthetank]

I'm just learning about this... but a Mag12 seems kind of big. Am I wrong guys?

 

[gregghia]

Yeah I was thinking a 7 or 9.5 but I got talked into a 12 for the flow... I have a 75gal AGA with overflow that is not in the corner but rather off set to the right....
Probably be about 4-5 feet of plumbing from sump to tank with 2 90 degree elbows. I will use a ball stop in the plumbing as well. Of course I would rather have more flow than not but also don't want to create a problem.
Can I stay with Mag 12 or go down to 9.5 or 7????

 

[frankthetank]

Well, I was thinking a 7. I was told to get a 5 for my 46, but I got a quiet one 2200 instead just because of price difference. A 12 seems too big to me.

 

[andy51632]

How much flow can your aga overflow handle? If it is like my 75gal aga overflow system it can only handle 600GPH. You won't need such a big pump because your overflow system won't be able to handle it. I would trade down to a smaller pump if that is the case.

 

[gregghia]

bump... anyone else have opinions on Mag 12 on a 75 gallon RR tank. My sump is a 30 gal. Also anyone have ideas on the 2 90degree elbows?

 

[f14peter]

I have a Mag7 for my 90g AGA, which gives me close to 500GPH at the 4-foot +change head, perfect for the 600GPH overflow.
I don't know for sure, but I think a 90-degree elbow in a pipe system essentially adds 1-foot of head.

 

[inawe]

At the present time I have a Mag 9.5 in my new 75g and am working on getting rid of my "in-house hurricane"! Like you, I only need about 3 feet of lift, so I figure I have a flow rate of somewhere around 800gph! The gushing noise from the overflow is terrible, probably because I'm trying to force 800g through a place meant for only 600g! I would look for the lightening to begin with a Mag 12!

 

[weberian]

Has anyone every tried heating up the PVC a little and putting it on a pipe-bending tool? I can't stand the head loss myself.
It's easy to lose your head over head loss.

 

[weberian]

Can you pull a 180 with spa-flex?

 

[turningtim]

The return pump size is based solely on the size of the overflow and what you intend on keeping the display tank. FO and softies 10-15x, LPS 15-20x, SPS 20-30x tank volume. Also what size is the drain in the OF 1" will only drain 600 gph so calculate head pressure of the pump at given head and make sure it is less but close to what the drain will handle.
Sump size will play a large part in turn over too. If you run a small sump then chances are that to much flow will result in micro bubbles getting back to the DT.
Also remember that backwash in a power loss must be calc'd in order to prevent a flood from the sump.
You MUST think of the system as a whole not just parts. All components have to work together or it will not function correctly!
HTH
Tim

 

[turningtim]

Originally Posted by Weberian
Has anyone every tried heating up the PVC a little and putting it on a pipe-bending tool? I can't stand the head loss myself.
It's easy to lose your head over head loss.

You can fill the pipe with sand and then heat to bend. But you will need some sort of heat tape to get uniform heat across the piece you are trying to bend. Spaflex can be heated with a heat gun to insure that it keeps its shape. Just don't pinch it!
Over all head is something that will always need to be delt with. But just have the proper pump and all is well......

 

[weberian]

Thanks, but have you done 180 degree bend with Spaflex? In other words, is it flexible enough to make a U-tube? I've never handled the stuff.

 

[turningtim]

Never needed to bend it that much. Yes it is fexible but its stiff and it has 1/8" thick wall. I would imagine that you could bend it that much but don't know if it would stay. Besides I always use clear plastic for u-tubes, they're cheap and you can see air inside......
Lowes and HD carry it, its in the tubing section (not plumbing). Check it out you'll see what I mean......

 

[halcyon_diver]

Pressure Loss varies is pipe size..
1" PVC 90= 2.5 feet of pipe
1" PVC 45= 1.0 foot of pipe
3/4" PVC 90= 2.0 feet of pipe
3/4" PVV 45= 0.5 feet of pipe
1" ball valve = 0.5 feet of pipe
3/4" ball valve= N/A
hope this helps

 

[weberian]

I just meant the shape of a "U", but I was thinking of a return line coming in over the lip of the tank. Two 90's plus a third to direct the flow to horizontal is a lot of head loss.
I'm going to try the sand-packed PVC bend. At least that'll eliminate two of the 90's.

 

[halcyon_diver]

Web..as was suggested before, you could fill the pipe with sand and gently heat it...ive done it before with a heat gun...just need to heat slow and bend slowly as well...i have made 90 degree and 45 degree bends but have not tried a 180...good luck and i hope this helps

 

[turningtim]

Originally Posted by Weberian
I just meant the shape of a "U", but I was thinking of a return line coming in over the lip of the tank. Two 90's plus a third to direct the flow to horizontal is a lot of head loss.
I'm going to try the sand-packed PVC bend. At least that'll eliminate two of the 90's.
That would be cool if you could. I'm wondering if the spa-flex filled with sand and then heated would do? I think I have some scrap, I may have to try that.

 

[gregghia]

Going back to the original part of the post....
I am running a Mag 12 on the overflow rated for 600 GPH. I BARELY have the ball stop valve restricting so i am almost at full flow. Its awesome.
I had to cut the bottom off of the mega-flow return pipe by about an inch to lower it as to let the water level actually drop some and I opened up the hole at the top ever so slightly to let it suck in more air. That thing is purring. Its not siphoning either its all gravity baby.
I think the best thing I did was I originally had my drain going to the sump with 2 90s. I replaced that part below the union with 1 45 elbow and now its a straight shot to the sump. Water is gushing down!

 

[sankysyuck]

If I were you I'd stick with the 12, especially if you plan on using 90's. As long as you put a ball valve somewhere on the return line you can adjust it to wherever you want. So if the flow rate is a little strong you can just turn the ball valve down and bam! no more problem. You do know that when you use PVC it will clog over time and the hole will reduce down to about a quarter of the size correct? Therefore a stronger pump may help you in the future.