Upgrading to Mag 18

I have been running a Mag 5 on my 90 gallon reef and have recently decided to upgrade to a mag 18. I was looking at the instruction manual on the Danner website and it says to use at least 1 1/2" pvc for the outlet. So, I figured "why not go for the 2"... ", until today when I went to look at the 2" ball valve and other parts at Home Depot. I was wondering if anyone else has used 2" PVC for a pump this size and if it would really make a difference over the 1 1/2"? It just seems like it would take up alot of space and might just be overkill, but I wouldn't mind running it with 2" if it really made a difference.

I also plan to run this pump externally. Anyone have any good or bad experiences with this as an external pump?

 

Hi DoTheEvo I'm currently running a Mag 18 on my 125 which I believe is 2' longer than your 90 watch the output on that thing not sure yours may be different im using 1 1/4" OD x 1" ID Vinyl hose from home cheapo. I spoke with someone from Danner Supreme and with that size hose at 3' 8" of hose and the 1" duck bill attachment on the end equals 6' of head pressure you will get 1125 gph. Hope this helps.

 

I've see this guys tank in person and he runs a Mag18.. I couldn't even hear the thing. He runs it submersible and says it doesn't add much heat.(no chiller).
ReefGodsCreations

 

Do you mean with 1 1/4" or 2"? Did you just call the number on thier website?

So it really doesn't add too much heat? I would love to run it in the sump, but with summer just around the corner I really want to keep the temps down. Dont know what to do. :-/

Thanks for your help guys.

 

No I meant just what I said I got the website of the Mag 9.5 box and went thru the contact us link then spoke with live tech support. Im Aim2pleez69 on You-Tube check out my video. Hope your overflow can handle that much water.

 

and not for nothing but Danner wasn't any help to me, the flow rating chart that comes with the pump is acquired with 2" PVC and it doesn't have the turns you'll have in your application So me and a buddy did an experiment we place the pump with the amount of hose I listed above and the duck bill attachment in a 30 gallon trash can full of saltwater we than placed and empty salt bucket at the exact same hieght of the rim of my tank and timed how long it took to fill the saltbucket then converted those seconds into minutes and then minutes into 1 hour.

 

That pump I think has a 3/4" inlet and 3/4" outlet. If you open up the pipe to 1-1/2 or 2", you will lose most of the pressure. It depends on what you want to use the pump for though. If it is only for your single overflow return, then a mag 7 is fine. The only reason why you'd want a bigger pump than that would be if you want to run the skimmer and other accessories off it, or use it solely for a closed circulation loop.

 

I have a 90g with a Magdrive 18 for about 4 yrs now and it works awesome. Quiet as a mouse and I dont see the "heat issue" that some ppl talk about and I have the pump in the sump. I dont use a chiller, just two fans. The plumbing is as follows; 1" pvc from the pump to the bottom of the drilled hole(about 5' long) which gets reduced to 3/4" pvc( about 2' and 3' of LocLine spary bars). The Magdrive company states that their pumps can be installed either internally or externally, but I've heard differently on the external application. Its not that it cant be done, it can, its just that the pump wont last as long as if it was installed internally. The water helps to keep it cool. As far as my GPH, I really dont know, but if I had to guess, I would have to say some where between 900-1200GPH flow.


Luna

 

I'm not sure what the benefits are of running that much water through your sump but I don't think going to 2" plumbing is worth it. You can get an estimate for how much the gph is going to change with the head loss calculator here. You might get an extra 50gph or so going from 1.5" to 2".

Reef Central Online Community

FWIW using a return pump for in-tank flow isn't very efficient. With that mag 18 you're using about 145 watts of power to get approximately 1300gph of flow.

One Koralia 4 (just as an example) is about 1200gph of flow and uses 8.5 watts.

Maybe that's not what you're planning on using it for, just something else to consider if you hadn't already.

 

You have a really cool tank Hevgotdat4u. I might try that same experiment to get a better idea of what the gph will be, thanks. I will be upgrading my overflow along with the pump to a CPR CS202 which I believe is rated for 1500 gph.

This pump will just be a return. I currently have a Mag 5 on almost 7' of PVC to the tank, I got a little crazy with the elbows n' such, and that is at about 150 gph. In the tank, I have 2 Koralia 3s and a Koralia 4 on a natural wave wavemaker, but I am still getting dead spots in the corners where brown algae is accumulating. So, I decided to upgrade to a bigger return and overflow and thought "why not go big...". "Go big or go home", right? I also wanted to get something that would be able to handle a larger system if I ever decided to get a bigger tank (which I probably will).

Thanks for the great calculator Screwtape.. going to 2" would only give me an extra 50 gph and I dont think it is worth it either.

As far as running the pump externally, I have heard from a number of people now that the heat issue isnt too much of a problem. So, the whole external thing is out. I have had enough spills on my floors, I would like to avoid any more. Thanks for the input Luna.


Thanks for all your help. I updated my sig so that you guys can get a better idea of what I have going on.