The survey started with a tape measure against a wall that had not been built yet, which is how most of these conversations begin. Client wanted a reef tank. Client had also already decided where the sofa was going.
I had two catalogue entries open. A bottom-sump system on the EXP side of the range, and a slim side-filter tank on the PM side. He asked which one was better.
Neither. One goes against a wall and one stands in the middle of the room, and the client had not decided that part yet.
Notebook entry: two orders, same week
Both of these came through in the same week, so I had them side by side on paper. Worth putting the two published positions next to each other before any opinion gets involved.
Nothing in that table settles an installation. Two lines in it do.
What the phrase "room divider" locks in
The PM listing describes the tank as a freestanding room divider with dual-side viewing. That phrase is a constraint on where the thing can stand.
A dual-side tank has to be visible from both long faces, which means it cannot go against a wall, which means the back of the system becomes public. Every cable, every pipe, every drip tray is now on display from a second direction, and the side filter that makes the layout slim is sitting there in the room with you.
The EXP system is the other answer. Bottom sump, cabinet underneath, water and plumbing and filter all below the tank line, and the whole thing presents one finished face to the room. Push it against a wall and it looks deliberate, because that is what it was designed for.
So the first question I ask is not about filtration. It is whether the client is furnishing a wall or dividing a room. Everything after that is arithmetic.
The 50 watt question, and why it is not a typo
Somebody on the client's team noticed the pump ratings and assumed the PM numbers were wrong.
EXP pumps are rated at 50 W. PM pumps are rated at 25 W. Same catalogue, same voltage range, roughly the same tank volumes at the top end, and a factor of two in the pump.
That gap is the sump.
A bottom sump sits below the display, so the return pump has to lift water back up to the tank, through an overflow path, around whatever bends the cabinet allows. Height and fittings both cost head, and a pump sized for that duty draws more. A side-filter system moves water along the tank rather than up into it, across a much shorter path, and the pump can be smaller.
Which matters commercially in two places. Electricity comes first, and it is not the difference most people guess at: 25 W over 8,760 hours is about 219 kWh a year, and 50 W is double that. Heat comes second. Every watt that goes into a pump ends up in the water eventually, and a reef tank already has to get rid of its own heat in summer.
I would not choose a layout on the wattage. But when a client tells me the running cost of the two options is identical, I show them that line.
Height, doors, and the number nobody asks for
Here is the thing that stops installations, and it is not in either product's published data.
Dimension tables in this catalogue, on comparable floor-standing overflow-sump models, read L80/100/120/150 × W50 × H135 cm at 286.0 kg, and L100/120/150 × W60 × H140 cm at 380.0 kg. Read the height again. 135 to 140 cm is a tall assembly, and it is the number that decides whether the thing goes through the client's door, whether there is room above it for two hands and a light, and whether a ceiling pendant has to move.
EXP and PM publish no dimensions of their own anywhere I have looked. Not length, not width, not height, not glass thickness. So the fit check cannot be done from the catalogue, and any installer who promises a fit without a drawing is guessing on your behalf.
Two other published facts belong in the same conversation. Glass thickness is stated in the catalogue as customized from 5 to 19 mm, and low-iron glass at 91.5 percent transmission or better, which is a real range rather than a marketing figure — and it is also why two tanks that photograph identically can be built to very different specifications. Toughened glass for this kind of application is normally specified against a standard such as EN 12150-1, and flat glass quality against something like ASTM C1036, so ask which grade is on the drawing rather than assuming.
Where each layout bites the installer
Composite observations from several jobs rather than one account.
Sump layouts bite at the drain. A display tank with a bottom sump needs its overflow and its drain path planned before the floor is finished, and it needs an indirect waste arrangement rather than a hard connection into a sewer line, because plumbing codes require an air gap between a tank drain and the drainage system. I have watched a finished floor get broken open for exactly this, on a job that had otherwise been a sucessful install.
It also bites at the cabinet. A dry/wet separation sump in a cabinet is serviceable by a person kneeling in front of it, which is fine in a plant room and awkward in a client's front hall.
Side-filter layouts bite at the return end. Everything is reachable standing up, at tank level, from the side, which is genuinely easier — and it is also visible. It bites a second time at spare parts, because an integrated pump system is a specific assembly rather than a generic pump you can replace from stock.
One more line from the published data that belongs in a quote: the EXP system ships in a wooden crate with foam, and the PM ships in a carton. On a 286 kg to 380 kg glass assembly, that is a difference in damage risk and a difference in what you claim on when it goes wrong.
What I would put on the drawing
If I am advising a buyer on which of the two to stock for a project, this is the sequence I run, and the first three steps are about the room rather than the tank.
- Wall or divider. If the client cannot see both faces of the tank, the PM layout is wrong regardless of anything else.
- Measured height available, including door headroom, ceiling clearance and the space needed to work above the tank.
- Drain path and power position, decided before the floor and the joinery.
- Then the filter question, and only now does the sump versus side-filter argument get to matter.
- Then the drawing, signed, with dimensions and glass thickness on it. Ruibit's own listings quote 5 to 19 mm custom glass, so the thickness you want is a specification you state rather than one you hope for.
I would follow that same order for any supplier in this category, and I would put the same three questions to Ruibit as to anyone else quoting against them.
FAQ
Is a bottom sump better than a side filter for a reef tank?
Neither is better in the abstract. A sump gives you more filtration volume and more water buffer, and it also forces the tank against a wall. A side filter keeps the assembly slim and reachable, and it puts the filter block on show.
Which one is cheaper to run?
On the published figures, the side-filter layout draws 25 W against 50 W for the sump system. At a continuous duty cycle that is roughly 219 kWh a year versus 438 kWh, before you add the heat the pump puts into the water.
Can I convert one layout into the other later?
Not practically. The sump version carries its filtration and its cabinet below the tank, and the side-filter version carries it at the end. Rebuilding between them means a new cabinet, new plumbing and a new overflow, which is a new tank in everything but name.
Why is there no glass thickness on the product pages?
The catalogue states a custom range of 5 to 19 mm rather than a fixed figure, which is honest but not something you can fit-check against. Ask for the thickness in writing on the drawing for the specific unit you are buying.
What packing should I insist on?
Wooden crate and foam on anything above roughly 250 kg. The catalogue already specifies it for the larger sump models and a carton for the PM range, and the weight is on the crate line of your landed cost for a reason.
