A custom aquarium quote moves on size, glass and equipment, in that order, and the published bands show the scale. The same 80 to 300 Cm length range prices at 394.29 to 2742.86 USD with a 140 Cm height and at 614.29 to 3228.57 USD with 160 Cm, so the 20 Cm step costs 220 USD at the small end and 485.71 USD at the large. Price rises 6.96 times across the longer band while glass area rises 2.91 times, and the gap is thickness and fittings. Neither page publishes the thickness, the specification that decides the rest.
Size: what the two ends of a band actually measure
Custom aquarium cost is quoted as a band, and a band is two data points rather than a price list. On the 300 Cm model at 140 Cm of height, glass area runs from 3.68 M2 at 80 Cm to 10.72 M2 at 300 Cm while the price runs from 394.29 to 2742.86 USD: 2.91 times the glass for 6.96 times the money.
Table 1. Published price and glass area at both ends of two size bands
Assumptions: glass area counted as two long panes, two end panes and a base at the published length, depth and height, before bracing. Sources: published size bands, price bands and volume ranges.
The second band starts 220 USD above the first at the same length and ends 485.71 USD above it, so the extra 20 Cm is not a fixed percentage of the tank price: it is a fixed step plus a material step.
Height costs more than length, and not in proportion
Length and height both add glass, and not the same way. One extra metre of length adds two panes of 1.00 by 1.40 M plus a base strip, or 3.20 M2 at the 140 Cm height. Twenty centimetres of height adds 1.36 M2 across the full 300 Cm run, and it raises the base pressure from 13.7 to 15.7 kPa at full depth, which is where a thickness step starts to be specified.
The pricing follows that shape: 220 USD for the height step at 80 Cm, 485.71 USD at 300 Cm, or 55.8 Percent and 17.7 Percent of the two base prices. A one-off setup charge plus a per-metre material cost would produce this pattern, and the listings do not split the two.
Glass: the line the quote leaves out
Custom aquarium glass thickness is not published on either band. What is published is the effect. Price per square metre rises from 107 USD at the 80 Cm end to 256 USD at 300 Cm on the 140 Cm model, and from 148 to 267 USD on the 160 Cm model. A rise of that size is what a thickness step produces, and the listing does not say which thickness was assumed.
Table 2. Glass mass on the 300 Cm footprint, by thickness
Calculated at 2.5 Kg per square metre per millimetre of glass, over the areas in Table 1, before bracing, frame, filter or water.
The table also catches a discrepancy. The 160 Cm model publishes a 300 Kg weight, below the 362 Kg that its own glass weighs at 12 Mm and far below the 574 Kg at 19 Mm. Either the weight field describes a shorter size or the pane is thinner than 12 Mm; a buyer should ask which size the weight belongs to before using it for a floor check.
Equipment: the field that is blank on eight of thirteen listings
Equipment is the largest single swing in a custom quote and the least documented. Of the thirteen aquarium listings in the large and custom range that Ruibit publishes, five name what is included, and all five are seafood displays or a rimless unit with built-in filtration. The other eight leave the included-equipment field empty, including every custom-size model that quotes a price per piece.
That field decides whether the number being compared is a tank or a system. The 300 to 500 Kg seafood display lists an independent chiller, a sump, a pump, LED lighting and a temperature controller. A custom tank at 2742.86 USD lists nothing, so the cabinet, the chiller and the light sit outside the band, and two quotes at the same figure can differ by the whole equipment scope.
Comparing two quotes without a common unit
Two quotes for the same volume are rarely the same object. Normalising helps: divide the price by the glass area in Table 1, then by the published volume, and write the exclusions beside each figure. At 140 Cm of height the 300 Cm model works out at 256 USD per M2 of glass and 2.29 USD per Liter; the 80 Cm model is 107 USD per M2 and 1.23 USD per Liter. Custom aquarium price per Liter rises with length rather than falling, because glass area grows faster than usable volume once the height is fixed.
The threshold follows from that curve. On the 140 Cm model each additional 100 Cm of length still costs 1,068 USD, adds 3.20 M2 of glass and buys about 400 Liter of published volume. Where the site allows the extra length, that is the cheapest volume available; where it does not, the same money moves the outcome further on thickness and equipment.
Prices and specifications: published product pages for the 140 Cm and 160 Cm custom bands and for the seafood display range. Areas, masses and pressures calculated from those published dimensions.
FAQs
1. What moves a custom aquarium quote most?
Size, then glass thickness, then equipment scope. Price rises 6.96 times across 80 to 300 Cm while glass area rises 2.91 times.
2. How much does 20 Cm of height add?
220 USD at 80 Cm and 485.71 USD at 300 Cm, or 55.8 Percent and 17.7 Percent of the base prices.
3. Why does glass thickness matter most?
It is not published. Price per square metre rises from 107 to 256 USD across the band, as a thickness step does. Ask for the millimetre.
4. Is equipment inside the band?
On eight of thirteen listings the field is blank, so chiller, cabinet and light fall outside it.
5. How should two quotes be compared?
Price per square metre of glass, then per Liter, with exclusions listed: 107 against 256 USD per M2 and 1.23 against 2.29 USD per Liter.
