Metering Pump Accessory Kit

Scope: accessory package required to put the three procured Grundfos DDC 6-10 AR-PVC/V/C-F-31I001FG metering pumps into service. The pumps were procured bare, with power cords only, so each mineral channel needs a complete suction, discharge, and injection accessory set: MP-101 for magnesium sulfate (MgSO₄), MP-102 for calcium chloride (CaCl₂), and MP-103 for sodium bicarbonate (NaHCO₃).

Recommendation

Do not buy three full-price Grundfos installation kits unless convenience is worth the premium. The official Grundfos 95730501 kit is the clean reference package, but at current distributor pricing it is roughly $347 per pump from Burt Process.

The better value path is:

1. Use Grundfos-compatible pump connection hardware at the DDC head.
2. Use commodity food/lab-grade bottles and tubing.
3. Use a reputable injection valve from Grundfos, Blue-White, LMI, or Stenner.
4. Keep the whole channel on one tubing standard: preferably 1/4 in ID x 3/8 in OD if converting to US accessory parts, or 4/6 mm if staying with the original metric Grundfos format.

McMaster-Carr is useful for tubing, clips, grommets, small NPT adapters, and mounting hardware. It is not the best first stop for the pump-specific DDC connection pieces or the final injection valve. For those, use a dosing-pump supplier such as Burt Process, Cannon Water, Pollardwater, Ferguson, Serv-A-Pure, Fresh Water Systems, or a Grundfos distributor.

Flow Direction

The DDC is not gravity-fed. It self-primes from the reservoir and meters under pressure.

concentrate bottle
  -> foot valve / suction lance
  -> suction tube
  -> DDC bottom port
  -> DDC top port
  -> discharge tube
  -> injection check valve / quill
  -> treated-water line

The upward arrow on the pump head is the pump-head flow direction. The bottom port is suction/inlet; the top port is discharge/outlet.

Reference Kit

The official kit is useful as the baseline for what a complete channel should contain.

Item	Notes
Grundfos 95730501	I006 PV/V/C-1/4"x3/8"-NL; PVDF body, FKM gaskets, ceramic valve ball; 1/4 in ID x 3/8 in OD tubing; no level switch. Burt Process lists it at ~$347.
Grundfos 95730503	Similar I006 PV/T/C-1/4"x3/8"-NL variant with PTFE sealing material, listed in Grundfos Product Center.
Grundfos 95730496	I006 PP/V/C-1/4"x3/8"-NL; polypropylene/FKM/ceramic version, listed by Grundfos as fitting DDA, DDC, DDE, and DMX up to 30 L/h.

Grundfos-style install kits normally include pump connections, a foot valve, an injection unit, PE discharge tubing, PVC suction tubing, and a bleed / deaeration tube. A surplus or open-box 95730501 around $75-$125 is a good buy. At $347 each, build the kit yourself.

Buy List Per Pump

Function	Recommended Part / Spec	Suggested Sources	Qty
Concentrate reservoir	1-2 L food-grade HDPE or PP wide-mouth bottle with screw cap. Prefer translucent HDPE so level is visible.	U.S. Plastic 2 L Diamond RealSeal HDPE bottle, U.S. Plastic 2 L rectangular HDPE bottle, Nalgene / Thermo Scientific lab bottle via lab suppliers.	1
Reservoir cap penetration	Drill the supplied cap and add a grommet or small bulkhead for the suction tube. Add a second small vent hole or filtered vent if the cap seals tightly.	McMaster-Carr grommets / bulkhead fittings; U.S. Plastic caps if spares are needed.	1
Pump connection hardware	Grundfos DDA/DDC/DDE pump connection package matching the chosen tube size. If using US accessories, ask for the U7U7 style connection set: 0.17" x 1/4", 1/4" x 3/8", 3/8" x 1/2". If staying metric, ask for U2U2 / I001: 4/6, 6/9, 6/12, 9/12 mm.	Grundfos distributor, Burt Process, Ferguson, Pollardwater, Xylem, or Grundfos Product Center.	1 inlet + 1 outlet set
Suction tubing	Clear PVC, PE, or FEP tubing; keep short. Use the same size as the pump connection. For US path, use 1/4 in ID x 3/8 in OD.	McMaster-Carr polyethylene/PVC tubing, Blue-White / LMI / Stenner tubing, Cannon Water.	2-4 ft
Foot valve / strainer	PVDF or PP foot valve with strainer and ceramic/chemical-resistant check. For the cleanest build, use the foot valve that matches the chosen injection-valve brand and tubing size.	Blue-White foot valve 71001-107 for 1/4 in ID x 3/8 in OD tube; Stenner foot/check accessories; Grundfos foot valve or rigid suction lance.	1
Discharge tubing	Opaque PE, FEP, or PTFE-compatible dosing tube. Same size as pump outlet and injection valve. For US path, use 1/4 in ID x 3/8 in OD.	McMaster-Carr polyethylene tubing; Blue-White / LMI / Stenner metering-pump tubing.	6-10 ft
Injection valve / quill	Do not omit. Use an injection fitting with check valve, not a generic open tube. Preferred budget choice: Blue-White PVDF/FKM for 1/4 in x 3/8 in tube.	Blue-White A-014NK-6A PVDF/FKM, 1/2 psi, 1/4 in x 3/8 in tube; Blue-White C-395NK-6A PVDF/FKM, 6 psi, diaphragm-pump style; LMI 37356 for 3/8 in OD tube; Stenner ball check valve family.	1
Process-line tee / port	Female NPT port matching injection valve, usually 1/4 in or 1/2 in FNPT. Use material consistent with the injection manifold.	McMaster-Carr, Swagelok, Parker, sanitary fitting supplier, or existing skid plumbing vendor.	1
Bleed / deaeration return	Small tube from DDC bleed connection back to the bottle, if the installed pump head uses the bleed port during priming. Grundfos literature calls this 4/6 mm or 0.17 in x 1/4 in.	McMaster-Carr tubing or Grundfos-compatible small tubing.	1-2 ft
Bottle restraint and labels	Clip, tray, or small secondary containment tub; labels for MgSO4, CaCl2, and NaHCO3.	McMaster-Carr, U.S. Plastic, lab supplier.	1 set

Multiply the quantities above by 3 for the full skid.

Best-Value Configuration

Use a US tubing ecosystem for the three new accessory channels:

• Tubing: 1/4 in ID x 3/8 in OD PE/PVC/FEP dosing tube.
• Pump fittings: Grundfos DDA/DDC/DDE U7U7-style connection pieces.
• Injection valve: Blue-White C-395NK-6A if you want the diaphragm-pump style 6 psi spring, or A-014NK-6A if you want a lower 1/2 psi cracking pressure. Both are PVDF/FKM with 1/4 in x 3/8 in tube connection.
• Foot valve: Blue-White matching 3/8 in OD foot valve, or equivalent PVDF / PP foot valve with strainer.
• Bottle: 2 L HDPE wide-mouth bottle from U.S. Plastic.

Expected cost is roughly $110-$180 per pump, depending on how expensive the Grundfos pump-head connection pieces are. That is a meaningful savings versus the $347 full kit while keeping the critical check-valve and pump-connection parts in the industrial metering-pump ecosystem.

Acceptable Budget Substitutions

• Bottle: U.S. Plastic / Nalgene / lab HDPE is preferred. A generic food-grade HDPE bottle is acceptable for bench testing, but use a real cap seal and restraint before final install.
• Tubing: McMaster-Carr PE/PVC tubing is fine if the dimensions match the fittings exactly. Do not mix 4/6 mm with 1/4 in x 3/8 in.
• Injection valve: Blue-White or LMI is the best price/performance tier. Stenner is common in water treatment and acceptable, but verify pressure rating, elastomer, and tubing size. A generic McMaster check valve alone is not ideal because it usually lacks the injection-quill geometry and tubing compression interface.
• Foot valve: Less critical than the injection valve. PP/PVDF with strainer is fine for these dilute mineral concentrates.

Material Guidance

The mineral concentrates are dilute MgSO4, CaCl2, and NaHCO3 solutions, so the material burden is modest. Good choices:

• Best: PVDF body, FKM or PTFE seals, ceramic or PTFE ball.
• Good: PP or PVC body, FKM/EPDM/PTFE seals, ceramic ball.
• Avoid: brass, copper, plain steel, unknown elastomers, and unlisted Amazon fittings in wetted service.

Open Procurement Checks

• Confirm whether the pump heads still have their suction/discharge valve bodies installed. If the bare pumps are missing the valve bodies themselves, buy the correct Grundfos valve kit before buying tubing.
• Confirm whether the final injection manifold wants 1/4 in FNPT, 1/2 in FNPT, or a sanitary tee with an NPT adapter.
• Choose exactly one tube standard before ordering: metric 4/6 mm or US 1/4 in ID x 3/8 in OD.