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Mag 5 pumps!! Help please
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bobfish
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Joined: 21 Aug 2006

PostPosted: 2008.03.22(Sat)16:36    Post subject: Mag 5 pumps!! Help please Reply with quote

Hello all! ANd happy easter!

since I have 4 days off I decided to finally go along and make my sump/refugium. I bought a 20 gallon tank and added the right dividers.
I then bought a automatic rapids overflow. Now to get the water back I went with a mag 5 pump. HIgly recommended by everyone I spoke with)
My proplem is the mag. Its an awsome pump! and I mean awsome! BUT it pumps the water way to fast for my over flow to keep up. I ran out and bought a flow adjust valve so that I could mount it onto the pump itself and connect the return then to it. I heard some where that this is a very bad idea. I can't remember why but before I go ahead and silicon it on and wanted evryone opinion. Should I do it or try something else?

please answer asap

thanks in advance
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pH.6.5 temp 78-81 soft water
Med-heavy planted tank
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FloridaBoy
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Joined: 04 Jul 2004

PostPosted: 2008.03.22(Sat)20:36    Post subject: Reply with quote

Your problem is not the mag, it's the feed from the o-box.

First, keep in mind, good flow/turnover is usually desirable.
So, my first choice would be to try and get another style of overflow to "keep up" with the pump. In other words try not to slow down the turnover.

My old overflow boxes had siphon tubes, dumping into a 2 inch flex feed, so if I needed more flow I was able to simply add a second or third siphon tube in the box, which usually evened things out.

If this is out of the question, then my next choice would be to return the pump for a smaller unit more matched to your system. I'm sure Mag makes a slightly smaller unit, I used a Hagen 802 as a sump return on a small tank for years and never had a problem.

I also kept a gate valve on an Eheim in a sump for years and never had a problem, but all pumps are different and you don't want to create too much back pressure by closing it off too much.

Keep tinkering, you'll figure it out. Also, consult your local retailer, they can probably hook you up with a balanced set up.
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Michael L.
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Joined: 20 Nov 2005
Location: Nanaimo, B.C, Canada

PostPosted: 2008.03.23(Sun)9:49    Post subject: Reply with quote

I have never used a mag pump on one of my setups, but I have been using a ball valve on my Eheim return pump for close to a year now.

On another note, silicone is probably one of the worst things you can use to connect plumbing in aquariums. It does not adhere well to PVC or vinyl plumbing. If you are using soft vinyl plumbing, use plastic hose clamps like these: http://www.smallparts.com/products/descriptions/chn.cfm .

If you chose to use solid plumbing, use a suitable chemical welding product and make sure it has plenty of time to cure (I gave it 3 days in the air and 7 days submerged in tap water when I set up my ATO.
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bobfish
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Joined: 21 Aug 2006

PostPosted: 2008.03.23(Sun)10:29    Post subject: Reply with quote

Yeah I think silicon is a bad idea I want something I could take apart if I have to. I have to figure out something. but what about the flow control ?
I'm not talking about keeping it closed while on but simply to be able to adjust the flow to a bit lower. A mag 5 is to strong for my 30 gallon. The Lfs won't take it back because I've already used it. And it cost me 130$ Why is everything so much more expensive in canada?

So flow control valve OK or not?
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38 gallon
pH.6.5 temp 78-81 soft water
Med-heavy planted tank
110 watts power compacts
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Michael L.
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Joined: 20 Nov 2005
Location: Nanaimo, B.C, Canada

PostPosted: 2008.03.23(Sun)12:17    Post subject: Reply with quote

It should be okay to have a ball valve on it. If you are worried about back pressure, get about 1 ft. of vinyl tubing, attach the ball valve to one end, and the other end to the Intake of the pump. Then attach the outflow of the pump to the return line.

This way, it restricts how much water can get into the pump, not how much can get out. This method is the exact opposite of the modification that many people can be seen doing on Nano-Reef.com, where you get a regular pump and drill out the shroud on the intake of a pump so more water can get in.

Let me know if this doesn't make sense and I will post a picture.
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dale
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Joined: 10 Jan 2005
Location: Abbotsford Canada

PostPosted: 2008.03.27(Thu)18:59    Post subject: Reply with quote

Hi Bob,

You can use a valve on a pump and restrict it as much as you want without any problem providing it is on the returnline (outflow) side of the pump and not on the intake side as Micheal suggested (sorry Mike). Restricting the intake may (will) ruin the pump.

Here's how to plumb it using rigid PVC.



The mag drive takes a 1/2" male threaded fitting in the outlet end. Using a threaded to slipfit coupler allows you to use PVC pipe to construct the returnline.
Using a small section of PVC pipe, connect the threaded fitting to a union fitting (this is a fitting that separates and allows you to disconnect the pump down the road for replacement or servicing).
Using another short piece of PVC connect a ball valve. This allows you to adjust the flowrate back to the display.
Using more PVC and elbow fittings continue the returnline up to the display tank.

To substitute flexible tubing instead of rigid PVC follow the same diagram but you will need to use barbed fittings for the union, valve and elbows and plastic hose clamps below the waterline.
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FloridaBoy
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Joined: 04 Jul 2004

PostPosted: 2008.03.28(Fri)10:22    Post subject: Reply with quote

Nice Dale,
that looks like what I had on my old Eheim, it worked great for years.
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Michael L.
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Joined: 20 Nov 2005
Location: Nanaimo, B.C, Canada

PostPosted: 2008.03.30(Sun)22:27    Post subject: Reply with quote

That's exactly how I have my Eheim rigged up in your diagram. Why is it that it damages pumps to have the valve on the intake? I have read conflicting information regarding that on a few occasions but couldn't figure it out either way.
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FloridaBoy
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PostPosted: 2008.03.30(Sun)22:36    Post subject: Reply with quote

Michael L. wrote:
That's exactly how I have my Eheim rigged up in your diagram. Why is it that it damages pumps to have the valve on the intake? I have read conflicting information regarding that on a few occasions but couldn't figure it out either way.


I'm not a pump expert but I think these products are designed to handle a little back pressure or head pressure with no problem, however starving the pump of water at the feed will lead to overheating and early failure.
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dale
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Location: Abbotsford Canada

PostPosted: 2008.03.31(Mon)22:16    Post subject: Reply with quote

To expand on FB's comments,

Here's an internal view of a Mag 5 (and most magnetically driven pumps):



The pump is designed to run with chambers (A) and (B) at about equal pressure and the restriction at (1) does little to change this because the resulting back pressure can flow between (A) and (B).

Restricting (2) however will create negative pressure in (A). The water in (B) flows out faster than water can be drawn into (A). This is called a pressure differential. This unevenness will cause the magnet/impeller assembly to either wobble on its axis or it will draw the assembly forward towards (A). The increased friction (resistance) causes the pump to draw more power in order to turn the magnet/impeller assembly (leading to heat up/burnout) and the wobble/drawing of the assembly causes wear on the ceramic shaft, impeller, pump housing or on all three.

Which is pretty much what FB said anyways.
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