Alright, help me decide. INT or EXT

Would you rather own an INT or an EXT?


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naps

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I have a IM 20L AIO and now that Tax Season is here, i would like to upgrade to a 50+ gallon tank. I can't decide if i want an Innovative Marine EXT 50/75 or an INT 50/75.

Here is my list of concerns:

I hate AIO's i found out. It is way too tight getting my hands in there, i hate having to pay a premium for "nano" crap that can actually fit in the rear chambers, i feel like mechanical filtration is "good enough" at best. I have a HUGE bubble algae breakout so getting to the return pumps every single day to clean them out is becoming a hassle and inconvenient due to the fact i have to remove the return nozzles in the display side, remove the heater from the back of the tank and put it to the front, which means i have to remove the tank lid and place it, then haphazardly put it back on over the heater wire temporarily, which i am not a fan of.

Here is what i want:
I want to be able to do easy maintenance. Being able to access a wide open sump and clean things without freaking out the entire display side would be awesome. I want real equipment sized for the tank+sump and not this "nano" stuff that i only use because it fits. I would like it to fit closely to a wall, which is why i am thinking INT but ease of maintenance and the ability to fix things or work on things easier is TOP priority which has me on the EXT. I love the smooth, seamless look on the outside of an INT tank but i also love the easyness of an EXT and not having to jam my hands down the internal overflow to fish out an escape artist ot fix a bulkhead.

WHAT DO YOU THINK?!
 

JumboShrimp

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From what I can tell, the objection most people have to an internal overflow is that it takes up a lot of 'real estate' inside the tank, and makes aquascaping a bit more difficult. I think those concerns are over-blown, and if I got an IM 50+ gallon, I would probably get the INT, personally. 😉
 

X-37B

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EXT all the way. I have 3 ext's, 170, 112, 50.
Easy access to all 3 sides.
One side is against the wall but still easy access to my ext 50.
20251214_133114.jpg
 
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edsbeaker

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I like a sump better than an AIO for ease of maintenance and hiding the equipment.

I think EXT vs INT overflow is a trade off depending on your personal taste. I value the extra space and flat back wall of an external overflow, so chose the Ext for both my 75 gallon and 170 gallon. There is really only two negatives, and if you are OK with them you will be happy with it. First, the tank does stick out 5” from the wall requiring a larger footprint. Also be sure having to see the plumbing won’t bother you.

image.jpg
 

PharmrJohn

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INT for me. I've only had EXT and I didn't like the look of all that stuff hanging off the back. I'm willing to give up a little space to avoid overhanging equipment. I just like things to look as clean as possible.
 

exnisstech

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Been tank shopping myself and like the ext. All of my tanks are int and I like the flat back wall look plus the extra room. I always keep my tanks far enough away from the wall that i can fit my arm behind it. I like to mount powerheads on the back unless it's a large long tank.
 

Kiiyo

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Ever the contrarian, I would prefer INT just so I can have the tank up against the wall.
One point I will say to be aware of regarding this. I bought a kessil with the arm mount for my tank that was basically pushed up against the wall, and I couldn't ever fully screw in and secure the arm to the bracket on the rim, so it's important to leave a little space.
 

mfinn

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I love my external overflow with the 3 drain option. My drain has been almost completely silent for 13 years with maybe 2 tweaks.
I made a false wall type thing to conceal the space behind the tank ( piece of wood that conforms to the tank and stand.)
 

dedragon

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I love my external overflow with the 3 drain option. My drain has been almost completely silent for 13 years with maybe 2 tweaks.
I made a false wall type thing to conceal the space behind the tank ( piece of wood that conforms to the tank and stand.)
^ this completely. very easy to cut a piece of wood, or my preference, a piece of acrylic cut to size and the color of the stand. very easy to do
 

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