Hydro-cooled miners · A2, A3, A4 series

Coolant for Bitdeer SealMiner Hydro

Q: What coolant does a Bitdeer SealMiner Hydro use?

Deionized or distilled water with a corrosion inhibitor, plus ethylene or propylene glycol antifreeze at 20 to 50% depending on how cold the site gets. The finished coolant must meet the water-quality limits in Table 3 of Bitdeer's Hydro Series Cooling User Guide: pH 7.0 to 8.7, chloride under 20 mg/L, sulfate under 10 mg/L, hardness under 1 mg/L, and copper, iron and aluminum ions under 0.5 mg/L each.

Q: Can I use automotive or heavy-duty engine antifreeze in a SealMiner loop?

It is not a good fit. Heavy-duty engine coolants are usually precharged with nitrite for cast-iron cylinder liners and are often buffered above the 7.0 to 8.7 pH window in the guide. SealMiner cold plates are aluminum, and the finished fluid has to hit the Table 3 limits.

Q: What glycol concentration should I run?

Pick the lowest concentration that covers the coldest fluid temperature the site will see, plus margin. Per Table 2, 40% ethylene glycol freezes at about -25 °C and needs at least 11.3 L/min per server; 30% freezes at about -16 °C and needs 11.0 L/min. Lower concentration moves more heat, so do not over-specify.

Q: How much coolant does a SealMiner Hydro container need?

Each server holds only about 0.7 L. The fill volume is set by the piping, dry cooler, plate exchanger and buffer tank, so take it from the system designer's fill schedule. A 275-gallon tote is about 1,040 L.

Q: Can I flush the system with tap water?

No. The guide calls for deionized water at 5 µS/cm or less for the pre-fill flush, for no more than 8 hours, then a complete drain before the coolant goes in. Tap water leaves chloride and hardness that attack the aluminum plates.

Q: How often should SealMiner coolant be tested and replaced?

Table 4 of the guide sets pH, conductivity, reserve alkalinity, appearance and inhibitor level every 2 months, and microorganisms, ions and metals every 6 months. Bitdeer recommends replacing the coolant after about one year of use.

Q: Can copper fittings be used anywhere in the loop?

No. Bitdeer prohibits copper in the circulation system because copper next to aluminum cold plates causes galvanic corrosion. Stainless steel piping and a stainless pump are recommended.

For Bitdeer SealMiner Hydro: A2 Hyd, A2 Pro Hydro, A3 Hydro, A3 Pro Hydro, A4 Pro Hydro, A4 Ultra Hydro. Blended and shipped from Taylor, Texas, with a certificate of analysis on every lot.

See the coolant Get a tote quote

The short answer

Quick answer

SealMiner Hydro units run on deionized water with a corrosion inhibitor and an ethylene or propylene glycol antifreeze, mixed to the freeze point your site needs. The cold plates are aluminum and copper is not allowed in the loop, so we supply a nitrite-free inhibited ethylene glycol premix (40% EG) for freeze-exposed sites and deionized water for the pre-fill flush.

Hydro-cooled bitcoin mining containers with rooftop dry coolers at a Texas site at sunset, with Alliance Chemical IBC totes and drums of coolant staged on the concrete pad

What to order

The products that fit this spec, and what each one is for.

Primary fill

Inhibited Ethylene Glycol 40/60, Nitrite-Free

40% ethylene glycol with a nitrite-free inhibitor: no nitrite, silicate, borate or amines. Freeze protection to about -22 °C (-8 °F), which covers a Texas cold snap with margin. Fits the 40% row of Table 2.

Freeze point: about -22 °C (-8 °F) · Quart to 330-gallon tote · COA with every lot

See sizes and pricing TDS SDS

Flush and make-up

Deionized Water ACS Reagent Grade

Conductivity under 1 µS/cm, well inside the 5 µS/cm flush limit in the guide. Use it for the pre-fill flush and for evaporative top-off only.

Quart to 330-gallon tote · COA with every lot

See sizes and pricing TDS SDS

Need a different concentration? We blend to the freeze point you specify, in pails, drums and 275- or 330-gallon totes.

What Bitdeer requires

The coolant rules from the manufacturer's published documentation.

CoolantPure or distilled water + corrosion inhibitor + EG or PG antifreeze, ratio set by freeze point

Wetted materialsAluminum alloy, stainless steel, EPDM, FEP

Not allowedCopper anywhere in the loop (galvanic attack on the aluminum cold plate); carbon-steel weld slag; cast-iron pumps

Coolant per serverAbout 0.7 L; the fill volume is set by piping, dry cooler and tanks

Flow at 40% glycol11.3 L/min or more per server; inlet 20 to 53 °C normal mode, 20 to 43 °C high-hash mode

Pressure350 kPa max at the server inlet; 3.5 bar relief valve on the system

Pre-fill flushDeionized water at 5 µS/cm or less, no longer than 8 hours, drained completely before filling

ReplacementTest every 2 to 6 months (Table 4); replace after about one year of service

Freeze point by glycol concentration (Table 2 of the guide)

Glycol	Freeze point, EG	Freeze point, PG	Min. flow per server
20%	-8.8 °C	-7.4 °C	10.7 L/min
30%	-15.7 °C	-13.2 °C	11.0 L/min
40%	-24.8 °C	-21.5 °C	11.3 L/min
50%	-37 °C	-33.6 °C	11.7 L/min

Source: Bitdeer Hydro Series Cooling User Guide, 2026-07-13 (Sections 2 and 3, Tables 1 to 4).

Spec check, line by line

Initial coolant requirements (Table 3 of the guide) against our supply

Parameter	SealMiner requirement	What we supply	Status
pH at 20 °C	7.0 to 8.7	Set to 7.0 to 8.7 at blending for SealMiner orders; measured value on the lot COA	Meets
Chloride	< 20 mg/L	Blend water ≤ 0.4 mg/L (deionized water specification)	Meets
Sulfate	< 10 mg/L	Blend water ≤ 1.0 mg/L	Meets
Total hardness (as CaCO₃)	< 1 mg/L	Blend water Ca ≤ 0.1 and Mg ≤ 0.1 mg/kg (about 0.7 mg/L as CaCO₃ at the limits)	Meets
Copper and iron ions	< 0.5 mg/L each	Blend water Cu ≤ 0.01 and Fe ≤ 0.01 mg/kg	Meets
Aluminum ion	< 0.5 mg/L	Not on the standard COA; ICP result available per lot on request	On request
Reserve alkalinity	2.9 to 3 mL	Measured per lot (ASTM D1121) and reported on request	On request
Microorganisms	< 100 CFU/mL	Not tested; freshly blended with deionized water in closed totes	Not tested
Appearance	Clear, no precipitate	Clear, colorless liquid	Meets
Nitrite	Not specified	None. Nitrite-free sodium benzoate inhibitor (SDS Section 3)	Meets

"Meets" rows are taken from our controlled specifications: the product technical data sheet and the deionized water specification we blend with. "On request" values are measured per lot and sent with your order when you ask.

Questions

What coolant does a Bitdeer SealMiner Hydro use?

Deionized or distilled water with a corrosion inhibitor, plus ethylene or propylene glycol antifreeze at 20 to 50% depending on how cold the site gets. The finished coolant must meet the water-quality limits in Table 3 of Bitdeer's Hydro Series Cooling User Guide: pH 7.0 to 8.7, chloride under 20 mg/L, sulfate under 10 mg/L, hardness under 1 mg/L, and copper, iron and aluminum ions under 0.5 mg/L each.

Can I use automotive or heavy-duty engine antifreeze in a SealMiner loop?

It is not a good fit. Heavy-duty engine coolants are usually precharged with nitrite for cast-iron cylinder liners and are often buffered above the 7.0 to 8.7 pH window in the guide. SealMiner cold plates are aluminum, and the finished fluid has to hit the Table 3 limits.

What glycol concentration should I run?

Pick the lowest concentration that covers the coldest fluid temperature the site will see, plus margin. Per Table 2, 40% ethylene glycol freezes at about -25 °C and needs at least 11.3 L/min per server; 30% freezes at about -16 °C and needs 11.0 L/min. Lower concentration moves more heat, so do not over-specify.

How much coolant does a SealMiner Hydro container need?

Each server holds only about 0.7 L. The fill volume is set by the piping, dry cooler, plate exchanger and buffer tank, so take it from the system designer's fill schedule. A 275-gallon tote is about 1,040 L.

Can I flush the system with tap water?

No. The guide calls for deionized water at 5 µS/cm or less for the pre-fill flush, for no more than 8 hours, then a complete drain before the coolant goes in. Tap water leaves chloride and hardness that attack the aluminum plates.

How often should SealMiner coolant be tested and replaced?

Table 4 of the guide sets pH, conductivity, reserve alkalinity, appearance and inhibitor level every 2 months, and microorganisms, ions and metals every 6 months. Bitdeer recommends replacing the coolant after about one year of use.

Can copper fittings be used anywhere in the loop?

No. Bitdeer prohibits copper in the circulation system because copper next to aluminum cold plates causes galvanic corrosion. Stainless steel piping and a stainless pump are recommended.

Quote a fill

Tell us the site, the number of totes or the system volume, and the date the coolant has to be on site. We reply with pricing, freight and lead time.

Bitdeer and SealMiner are trademarks of their respective owners. Alliance Chemical is not affiliated with or endorsed by Bitdeer. Requirements are quoted from Bitdeer's published Hydro Series Cooling User Guide (2026-07-13); confirm against the current guide and your warranty terms before filling.