For most buyers, an OEM aquarium order is a black box. You send a drawing or pick a size, you pay, and weeks later a crate appears with a tank inside. Between those two moments sit six process stages, and each one is a place where quality — or cost — quietly enters the product. This document walks that sequence as it runs in a working glass-tank plant, notes what each stage controls, and what a buyer should verify at every step. It is a reference, not a pitch; where specific figures appear, they are published listing data or values a factory should confirm on its own spec sheet.
Stage 1 — Glass cutting
The process starts with the raw pane, and this is where the most consequential decision was already made before any cutting: the glass type. Float, ultra-clear and low-iron glass come from different raw-material specifications, and the difference (primarily iron content, which reads as a green edge cast in thick panes) cannot be corrected later. Ruibit's Jiangxi plant builds its display lines from ultra-clear/low-iron stock — the spec sheet rates transmission at 91.5% — and quotes thickness per size rather than applying one chart to all tanks, because water pressure scales with depth, not with length.
Cutting itself is CNC-controlled on straight panels. What a buyer should verify at this stage: that the factory can state a dimensional tolerance for its cuts, and that edge condition after cutting is treated as a controlled parameter rather than an afterthought. A supplier that cannot put a number on cut accuracy will also struggle to put numbers on everything downstream.
Stage 2 — Edge processing
Raw-cut glass edges carry micro-fractures from the cutting wheel — invisible, but they concentrate stress exactly where the silicone seam will later live. Edge processing (grinding and polishing) removes that damaged layer. Two specifications matter:
- Flat polish : the edge is ground smooth and uniform, which affects seam adhesion and handling safety.
- Bevel or arris : corner softening that improves both safety and the optical finish where panels meet.
Polished edges are one of the fastest ways to tell a premium build from a commodity one without opening a spec sheet; run a finger along a finished edge and the difference is immediate. Ask the factory which edge process their standard line uses, and whether it changes for larger panels.
Stage 3 — Bonding and curing
The tank becomes a tank here. Panels are assembled with structural aquarium silicone — a Wacker 121-class adhesive — applied with tooled seams so the bond line is free of air pockets. Two engineering points deserve emphasis:
- Seam width and glass thickness interact. The silicone joint is sized relative to the panels it joins; changing thickness without revisiting the seam spec is a design error.
- Surface drying is not full strength. Structural silicone reaches its rated bond strength on a documented cure schedule, not on a calendar guess. Rushing cure time to meet a ship date is the classic shortcut behind "mystery leaks" that appear in month three — which is why cure is treated as a controlled step before any water touches the tank.
Stage 4 — Water testing and QC
Before a tank is allowed anywhere near a crate, it is water-tested. This is the control point that makes a warranty clause meaningful: a 1-year warranty on a tank that was never filled at the factory is a promise about a process that didn't happen. Ruibit water-tests every finished unit before crating and keeps the QC step in the order timeline for a reason — the test is part of the manufacturing sequence, not an optional extra.
Compliance sits at this stage as well. The 100-gallon ultra-clear line carries CE, UKCA and RoHS documentation, and the supplier itself holds TÜV Rheinland verification (an assessment of the facility, not a per-unit certificate — worth knowing the distinction when a certificate is shown to you). Electrical components run 110–240 V, which simplifies stocking for U.S. and EU markets under one SKU.
Stage 5 — Packing
Glass tanks fail in transit for one reason more than any other: the crate lost its shape under load, and the tank inside absorbed the shock. Export packing therefore follows a repeating formula across serious factories: reinforced wooden framing, foam isolation between glass and wood, and fumigation-free lumber so the crate clears customs without fumigation holds.
The numbers are worth asking for before the PO, because they are your freight estimate. Two published examples from our catalog: the low-iron 100-gallon reef system crates at 120 × 60 × 145 cm, 286 kg gross; the 300-cm stream tank goes out at 310 × 60 × 135 cm, 580 kg gross. Multiply gross weight by the ocean rate (about US$0.84/kg via Maersk, 50 kg minimum, ~17–24 days transit) for a defensible freight estimate — "free shipping" is never free, only folded in.
Stage 6 — Delivery and documentation
OEM lead times on the fish tank lines run 7 days for 1–20 pieces (1–50 on the custom line), with larger quantities quoted per order. Shipping terms on the listings span EXW, FOB, CIF and DDP — the choice between them is a risk-allocation decision (insurance, freight and customs sit with whoever the term assigns them to), and it belongs in writing before production, not after. The same applies to the commercial documents: packing list, invoice, and any certificate the destination market requires. A tank that is perfect and paperless is, at the border, a tank that does not exist.
Common misconceptions
"A sample proves production quality." A hand-built sample demonstrates design, not repeatability. Production quality lives in the process controls above; ask what a production unit shares with the sample (same glass spec, same silicone, same test) rather than assuming.
"Glass thickness follows a universal chart." It does not; depth, span and bracing interact. The correct answer to "what thickness" for your size is a number from the factory's own engineering sheet for that exact dimension.
"Cheaper packing is a reasonable saving." Packing is roughly 1–3% of a premium tank's cost and 100% of its arrival condition. Saving it is the highest-leverage false economy in the industry.
"Certificates are per-unit guarantees." Some are (CE/UKCA/RoHS relate to the product's compliance); some are facility assessments (TÜV-type supplier verification). Ask which one you are being shown.
Appendix — process reference
Q: What information should I send to get an accurate OEM quotation? A: Target dimensions (length × depth × total height, noting whether height includes the cabinet), species and water type (they set glass and filtration spec), cabinet finish, voltage market, and destination port. The more fixed the parameters, the closer the first quote is to the final invoice.
Q: How long does a full OEM order take? A: On the standard fish tank lines, 7 days for 1–20 pieces once the drawing is confirmed; the custom large line quotes 7 days for 1–50 pieces. Drawing-based work for genuinely new dimensions adds an approval cycle before production.
Q: Is low-iron glass standard or an option in OEM builds? A: The display lines referenced in this document are built in ultra-clear/low-iron glass as standard. Specify the glass class in your drawing regardless — it protects both sides from an assumptions dispute later.
Q: What does a water test actually prove? A: That the assembled seams hold water at the factory, under controlled conditions, before the unit is committed to a 17–24-day ocean crossing. It does not replace the buyer's own arrival inspection — which should happen before the crate leaves the dock, not after the tank is installed.
None of this is proprietary — any competent glass-tank factory runs a version of it, and a good one will walk you through theirs. The point of reading about it is knowing which questions separate a process you trust from one you hope for; in OEM buying, that difference is usually just a spec sheet away. The reef system listing , the custom large line and the 100-gallon ultra-clear line all publish the stage-level data discussed above; a request for their process checklists is a normal part of due diligence.
