plumbing for mag 18 return lines

[dutt7]

i currently have a mag 24 with 1" pvc pipes for my return line. it gets to the top of the tank and tee's off into 2 3/4" pvc lines. I want to down grade to a mag 18 and was wondering what everyone thought about using the same lines. i know the mag comes with a 3/4 male threaded fitting, but I could go from that and get a 1" to 3/4" coupling to make the connection. does anyone think that this may affect the pump in a negative way?

[Nano_reeflover]

It will be fine. I used a 1'' to 3/4'' reducer on the output of my mag 9.5 and it worked great.

[Fast Fred]

Agreed! You should be fine.

[dutt7]

i guess i'll go ahead and try it. i really liked the amount of flow i had, just heat of the water was uncontrollable. not to mention the 18 consumes alot less energy than the 24.

[hahnmeister]

It will work, but for the most flow, two 1" lines or a single 1.5" line are what the mfg suggests.

[tabndust]

mine was ran with 1.5 return split into four .75's at the tank and i got pretty decent flow

[dutt7]

well i got the 18 and have it hooked up. it still provides good flow. and still keeps the tank pretty warm. not as hot as 24 but still warm.

[mstrianse]

What size tank do you have? I was thinkingabout getting a mag 18 for my 180rr.

[dutt7]

its a 150 with 40 gallon sump

[kgross]

If you want max flow out of your pump change out your lines to 1 1/4 inch or 1 1/2 inch rather than the 1 inch. If you only want ok flow out of the pump stick with your inch line and it will work fine just use a reducer where you pipe mounts to the pump.

Kim

[bapski]

not meaning to hijack OP. but since you guys are talking about pumps, might as well throw this question.

i have 130 gal. FOWLR tank with a mag24 running a closed loop with SCWD. i am using only 3/4 lines. would this just be fine? or is it way too overkill?

reason i only have 3/4 lines is because ive upgraded my pump from a mag12 and used the 3/4 pvc pipes.

im using the mag12 as a return pump for my fuge.

[kgross]

Overkill, not even close with your plumbing. I think it is very hard to go to much flow on a saltwater tank, unless you are trying to replicate a very calm lagoon envirenment.

Bapski, with the plumbing that you have you are introducing a lot of heat and wasting electricity with your mag 24 pump. if you want max flow out of that pump you need to upgrade the plumbing to atleast 1 1/2 inch, then split it off and only put 1/2 the flow through the squid. With the 3/4 inch lines you are getting less than 1000 gph out of that 2400gph pump. Depending on how much head you have it could be as low as 500 gph with the squid on it.


Kim

[bapski]

<a href=showthread.php?s=&postid=7189306#post7189306 target=_blank>Originally posted</a> by kgross
Overkill, not even close with your plumbing. I think it is very hard to go to much flow on a saltwater tank, unless you are trying to replicate a very calm lagoon envirenment.

Bapski, with the plumbing that you have you are introducing a lot of heat and wasting electricity with your mag 24 pump. if you want max flow out of that pump you need to upgrade the plumbing to atleast 1 1/2 inch, then split it off and only put 1/2 the flow through the squid. With the 3/4 inch lines you are getting less than 1000 gph out of that 2400gph pump. Depending on how much head you have it could be as low as 500 gph with the squid on it.


Kim

im kinda newbie. would you be kind to elaborate further? 1 1/2? at least? i was thinking of putting back the 1" that i tried for a mag7 (one of the guides i read suggested using 1" pvc pipes for a mag7).. hmm.. think ive got $$ left to assemble another closed loop..

am not sure what you mean by only putting 1/2 the flow to the SCWD.

[kgross]

To elaborate, the flow through the pipe creates friction in the pipe, the faster the water flows through the pipe (against the edge) the more friction is created. If you go with a large diameter pipe (with the same flow) the speed of the water next to the pipe is much lower so you have much less friction in the pipe. The friction in the pipe creates extra pressure that the pump has to overcome to pump water. The way a centrifugal pump works is that it puts out less flow if it has to pump against more pressure. So by going with large pipe you will get much more flow.

For example using the head loss calculator here on reef central, with your mag 24 pump and 10 feet of 3/4 pipe (horizontal not vertical) with no other fittings you will only get 1200 gph out of that pump. If you change the pipe to 1 1/5 inch you get over 2100 gph out of the same 10 feet of straight pipe. If you add elbows and other fittings you will decrease the flow even more with the 3/4 pipe.

On the squid, the reason I say to only put 1/2 the flow through the squid (or even better move the squid to your return rather than you closed loop), is because of the head pressure that the squid creates the intake and outlets of the squid are normally less than 1/2 inch inside so you create a lot of friction, plus the gears that make the unit work create friction causing a lot of head pressure and slowing down the flow. If you put a T on your closed loop and run part of the water through the the squid you can valve it so you are only trying to push say 600 gph through the squid you should be able to get close to 1000 gph out of the other returns, or just use the squid on your return and get the full 2000 gph + out of your mag 24.

Just to give you another example with that same mag 24 pump if you move the pipe up to 2 inch you will get over 2300 gph. For an ok rule of thumb if you want to move around 500 to 750 gph use atleast 1 inch, 750 to 1250 gph use atleast 1 1/4 and over 1200 to 2000 use at least 1 1/2, for over 2000 you will want atleast 2 inch pipes unless you have a high pressure pump.
Kim

[bapski]

by putting 1/2 flow to the SCWD this would mean id have to get something like this? http://www.marinedepot.com/md_viewItem.asp?idproduct=FT2573

think having the scwd will be out of the question since i have a UV sterilizer attached to it.

thanks for your input btw. really appreciate it. im attaching pic of my closed loop setup from my pump. i would really appreciate more ideas. thanks again.

http://img.photobucket.com/albums/v347/bigboygelo/100_3671.jpg