So before i go into why i'm exploring a closed system for my build let me explain my unique situation. First i have an all tempered glass aquarium (Thanks Sean from Brockton!) meaning no drilling, second my basement floor is not level, my filter room is 6" lower than my display room, third the ceilings in my basement are low due to a bulkhead for my HVAC system and that's not going to move. So i can't raise my tank any higher or else in-tank maintenance will be as imaginary as your girlfriends 
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So because of the unique placement of my tank, i'm exploring the unique benefits to having a closed head system vs open. The primary reason i'm exploring this type of a system is space requirements. In order for a open system to function property, water levels are looking to be equal in both tank and filter, rather pressure. Meaning my filter system needs to be raised off the ground a significant amount (top of aquarium is 60" above filter floor). Any suction system to move water from the tank to the open system will either be consistently running due to pressure gradient, or a pump since i have to go up above the rim of the tank.
A closed system, like i'm exploring, works only when pressure is lowered in the canister portion of the system no matter the height of the filter relative to the tank. Much like smaller canisters, which can be tucked anywhere around a tank, i can slam this canister right on the floor if i wanted. Another benefit of a closed system is humidity control. My home has a significant problem already (poorly constructed) and I've already devised a tight hood for the aquarium. Open systems while they can have lids but not as tightly fitted
Further, I hear you when it comes to canister neglect. But any filter can be neglected with the wrong owner. My design, if it works properly, will incorporate a swirl to help filter larger debris before up flowing through mechanical filter then down a central tube full of bio balls. Just like open systems i've planned back washing and drains into each section. (scrubber pads are easy to lift off the top)
I'll keep you updated as parts come in
. So because of the unique placement of my tank, i'm exploring the unique benefits to having a closed head system vs open. The primary reason i'm exploring this type of a system is space requirements. In order for a open system to function property, water levels are looking to be equal in both tank and filter, rather pressure. Meaning my filter system needs to be raised off the ground a significant amount (top of aquarium is 60" above filter floor). Any suction system to move water from the tank to the open system will either be consistently running due to pressure gradient, or a pump since i have to go up above the rim of the tank.
A closed system, like i'm exploring, works only when pressure is lowered in the canister portion of the system no matter the height of the filter relative to the tank. Much like smaller canisters, which can be tucked anywhere around a tank, i can slam this canister right on the floor if i wanted. Another benefit of a closed system is humidity control. My home has a significant problem already (poorly constructed) and I've already devised a tight hood for the aquarium. Open systems while they can have lids but not as tightly fitted
Further, I hear you when it comes to canister neglect. But any filter can be neglected with the wrong owner. My design, if it works properly, will incorporate a swirl to help filter larger debris before up flowing through mechanical filter then down a central tube full of bio balls. Just like open systems i've planned back washing and drains into each section. (scrubber pads are easy to lift off the top)
I'll keep you updated as parts come in
i also have decided a split filter may be best. Using a 55gal open barrel as a mechanical filter box and heater area that is drawn off of by a closed 30 gal for bio filter. The pump is the lowest point, in order to help it draw and if i need to drain the system.
