180 FOWLR Design/Setup


New member
Howdy, I'm Dave and am setting my main tank up on one end of my upstairs living room, with a 75 gal sump ~10' almost directly below it in the basement, offset by only a few feet lengthwise.

I've yet to decide whether I'll actually build the tank partially into the wall which divides the living room from the master bedroom, or build a stand. More confidence in my framing skills than my furniture building, but am weighing all.

Components I've purchased;

-New Aqueon Pre-Drilled 180 w/MegaFlow Overflow Sys
-used 75 gal tank, (48x18x21") converted to sump
-used ETSS-600 Pro skimmer
-Iwaki MD-55RLT (skimmer)
-(2) Iwaki MD-40RT (sump return)

My immediate questions regard plumbing the sump. It's yet to be drilled. I imagine I'll want to do more internal modifications to it, perhaps even remove all that has been fixed and start over. Pics below. I'm still looking over basic sump designs for my desired system.

First off, Aqueon states each side of the the MegaFlow Overflow Sys is rated for 600 gph.

According to the pump curves, with 10' of head, a MD-40RT will pump 11 gpm, 10% more than above.

Interestingly, the head loss calculator on this site shows 659 gph when I plug in the 40, a pipe diameter of 1.5" and the appropriate other values.

Not knowing exactly how my sump will end up I do know that my returns will take a suction on the opposite end of the sump that the 55 for the skimmer will.

First question; shall I have one large hole (1.5"?) drilled and then 'y' off to each 40's suction or would a pair of 1" holes, one for each pump, be preferable? My first concern is tank structural integrity but just as important is bulkhead leak potential.

The sump in the basement will be placed on a stand who's surface is likely going to be ~ 3' off the floor (main consideration here is optimal height for maintenance).

Second question; knowing the skimmers pump will take a suction off the opposite end, and that this chamber is either next to or part of the chamber where the main tank also drains, will it be preferable for the 55 to take a suction off one side or the other (front or back of end) as opposed to the center line of the end of the tank?

Other thoughts are that I'll run all, including a pair of Tunze Controllable Turbelle Stream 2 6105's and LED's (perhaps 3 Kessel A360W's), with a Neptune Apex Controller.

I plan on an adequate amount of quality live rock and read a 'thumbrule' of 1-2# gal. I also understand that the weight of the rock isn't as necessacarily an accurate a descriptive, as we're interested in the how porous the rocks are. My closest fish shop (75 miles away) seems reliable and the owners have been very helpful and got me good prices on the above (although I purchased the skimmer off the bay).

He recommends Walt Smith Ultra grade rock and offered it @ $4.75/lb. I understand it's not necessary to build the entire structure with live rock, but a more affordable 'base' rock can be purchased.

Perhaps I should also mention my desired stocking. Half of the 4 fish I consider 'must haves' eat inverts, which is a bummer, so no cool shrimp.

These 4 are;
-Yellow Tangs
-Regal Tangs
-Picasso Trigger
-Porcupine Puffer

I read Surgeons can/will be aggressive towards each other, and am not sure if I can keep Yellows and Regals together but also read that each can be stocked as a shoal of 3 or more if introduced together.

I think it'd be pretty cool to have up to 5 Yellows and 3 Regals.

Along with one Picasso and one Porcupine Puffer, I also really like the look of the Huma Rectangle Trigger.

I have yet to determine how many inches of fish I can comfortably accomodate. I do understand it will come down to how well this system handles the bio-load, as well as how much space each fish requires to feel safe.

I would also like a few other fish but have yet to conclude which. A few I'm considering are Dwarf Angels, and like the looks of the Flame, Potters and Koran, for example.

Also interested in a Longnose Hawkfish and Sailfin Blenny.

I do plan on having an RO/DI and likely an ATO.

Last pic is of the end of the room where tank will be. It measures 12'-1" across, with an inset of 34" (notice shelves on right). I plan on placing the main tank ~ 2' to the left of the shelves.

My experience is limited, but I'm a good learner. Had a 75 gallon marine tank with an undergravel filter and magnum set up about 30 years ago. Was doing well untill my wife and the US Navy kilt everything.

Any thoughts/suggestions will be most appreciated.


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New member
Did you consider returning the two iwaki 40's and just get a single iwaki 55 in their place? Save you money on the monthly electrical bill (1.9 amps times two vs 1.6 amps) and also give you the proper flow under what the overflow boxes are rated at?

2-5 times a hour turnover is what you need to shoot for, anything in that area you will be fine.

It's not really inches of fish but the type of fish. 10 inches of puffer is a lot different then 10 inches of queen angel, queen trigger or sea horses :)

I have 3 yellow tangs in my tank.... Works great! Just need to add them together when you get to that step. You can also mix types of the zebrasoma family... So a few yellows and a purple or something like that. You can also do multiple acanthurus tangs as well as other types.... But again its more about the attitude vs inches


New member
A single 55 for return was my initial thought but figured since there are 2 tank outlets I could increase my flow and gain some redundancy with the pair of 40's, throttled back if necessary, one of which will give me adequate turnover. Was also considering the possibility of going to a lower sump flow at night via this controller and alternating which pump shuts down. Don't know how good of an idea that really is, for example whether it may affect skimmer ops.

But one 55 would be perfect. Hmm. I wonder if I've got too much pump for the skimmer. Mfgr recommends either a 40 or 55 but this sure seems like a lot of pump. Would be cool if I could trade a 40 back in towards a controller.
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New member
Viggen, thanks a bunch. Having more pump than overflow, which with the curves and head loss calculator it looks like I presently do, although not by a lot, doesn't seem like the best plan. OK, I think going to a single 55 for the return is a real good idea and will pursue that.

Keep the 55 for the skimmer?


New member
Usually those type of skimmers work better with a stronger pump. Seemed like the smaller one is usually the minimum pump for it to work and the larger one is more ideal..... I have personally stayed away from those type of skimmers due to the electricity and noise they suck up to work. Yes they do work extremely well when given the power pump.....

I do agree that redundancy is great.... However you would be paying almost twice as much in electricity vs a single 55. I also think that turning pumps on/off is asking for problems. They are made to run 24/7 and not turn on and off throughout the day. I personally would not put the pair of 40's on a timer. Instead... Return one pump and trade it in for a 55. Then keep the other iwaki 40 on the shelf incase a put craps out on you and you need a replacement. These pumps are extremely well built and should last well over 20 years with zero maintenance! They just make a bit of noise :( running two 55's you also have the ability to simply swap those if the return pump would go out. Yes you would be w/o a skimmer until a new pump arises but that shouldn't be a problem....