Mag 12 or 18, Opinions

[Strength&Honor]

Well I was discussing ealier wether orn ot to go with 1 in or 1 1/4 in bulkheads (as some may remember) but finally decided to go with 2 1 inch bulkheads that will both be overflows into my sump. Now that this is decided I cant decide wether or not to go with a mag 12 or 18 pump for best results and best sump usefullness.

At my head ft the mag 12 will push out 11 gph while the mag 18 will put out 1300 gph. I thought I was firm on going with a 12 but havent been able to find a used one and have a very good option on a 18. However I dont want to push my overflows to the max and want some leway... I dont really plan on using the sump return for flow addition in the tank but I dont mind it.

What I was wondering is a 18 going to push the 2 overflows (one dorso standpipe and one just open standpipe) to the absolute max and thereby hindering the overflows surface skimmering abiilty, or would a 18 be ok? Any advice and opinions is appreciated

(I dont know how much 2 inch bulkheads can handel gph wise also)

 

[Krish]

Well, I'm also one who doesn't like to push things to their limits. I'm not sure what your overflows are made to handle, but just going on the CPR overflows, you can look at the chart I copied and pasted below that tells you how much each overflow can handle using the different bulkhead sizes. Not sure if it is exactly the same, but may give you some idea. As for which one to go with, I personally don't like more than 800 gph of flow through my sump, but that's just me. I like the flow slow enough to give my skimmer more time to catch the junk passing through, but others may argue, the more water passing through the more junk the skimmer gets a shot at so I guess there's a pro and con to both. Also, I've heard that the mag18 produces a lot more heat than the mag12, but I've personally never experienced it first hand so I can't say for sure. If you have the opportunity to get the mag18 and are afraid to push your overflow to the limit, then you can just put a ball valve on the output which will slow it down to where you want it and then if you decide down the road you want more, then you just open the valve. HTH and good luck

Model Flow Rate Outflow Size Width
CS50 300 GPH 3/4" Bulkhead 6 1/2"
CS90 600 GPH 1" Bulkhead 8"
CS100 800 GPH 1" Bulkhead 10"
CS102 1400 GPH 2-1" Bulkheads 10"
CS150 1600 GPH 1 1/2 " Bulkhead 10"

 

[mgoblue]

go w/ mag12's.
i remember anythting over this
makes too much noise.

 

[Krish]

Welcome to RF "mgoblue"

 

[mfinn]

If you used the 1-1/4 or even 1-1/2" bulkheads you wouldn't have to worry about the pump. You could use one (pump)or the other without worry. Why not just go with the bigger ones. You still have to drill the holes and you still have to buy the bulkheads, if you spend a $1 more on the bulkheads, so what.
It sure doesn't hurt anything and it will give you more options in the long run.

 

[bc_slc]

If you don't really care about the extra flow provided by the return pump, and your bulkheads are 1inch x2, then I would go with the Mag 12. It will provide a nice supplemental flow to the tank, will use less electricity, likely be less costly up front, be less noisy and not stress the overflows.

Mat