Red Sea Reefer Inner Downpipe S-850/S-1000 & G2 900/S-850/S-1000
Water type
Saltwater + Reef
Fits
Reefer-S 850, Reefer-S 1000, Reefer-S 850 G2, Reefer-S 850 G2+, Reefer 900 G2, Reefer 900 G2+, Reefer-S 1000 G2, Reefer-S 1000 G2+
Part no.
43315 (R43315)
Red Sea Reefer Inner Downpipe S-850/S-1000 & G2 900/S-850/S-1000
The genuine Red Sea inner downpipe for large Reefer overflow boxes. Part number 43315, fitting the Reefer-S 850, Reefer-S 1000 and the G2 and G2+ versions of the Reefer 900, Reefer-S 850 and Reefer-S 1000 — the inner sleeve that sets the water level and downflow rate into the sump.
Key features
- Genuine Red Sea part 43315 — matches the factory fitment exactly, no adapters or trimming.
- Sold singly — the standalone inner downpipe only; it doesn't include the outer downpipe or the separate sump connector pipe set.
- Correct diameter and seal profile for a direct swap into the overflow box on the models it fits.
Will it fit my tank?
| Fits | Does not fit |
|---|---|
|
|
We haven't been able to confirm whether this part also fits the newer G3 generation of these sizes — if you have a G3 model, check with us before ordering rather than assuming fitment.
Not included
This is the inner downpipe only. The outer downpipe and the separate sump connector pipe set (Red Sea part R42493) are not included and are sold separately.
Suitable for, and not suitable for
- Suitable for: replacing a cracked, warped or leaking inner downpipe, or restoring proper silent overflow function after biofilm buildup has changed how the overflow drains.
- Not suitable for: the Reefer 3XL 900, XXL 750, or any other Reefer size not listed above — each has its own dedicated part.
Care and maintenance
Clean downpipes during major maintenance. Biofilm buildup inside overflow plumbing is the most common cause of gurgling or splashing noise that develops gradually rather than appearing overnight — a clean is worth trying before assuming the part has failed.
Warranty and delivery
Covered by your rights under Australian Consumer Law. Standard parcel delivery.
Goes well with
- The matching outer downpipe — if both are original and one has failed, check the other for wear at the same time.
- Sump connector pipe set (R42493) — a related plumbing spare for the same Reefer size range.
Common questions
Will this fit my Reefer 900 G3?
We can't confirm that — Red Sea's G3 generation may use a different part. Contact us with your model before ordering if you have a G3.
Is the outer downpipe included?
No, this listing is the inner downpipe only.
What symptom does this part usually fix?
A cracked, warped or heavily biofouled inner downpipe, or persistent overflow noise that cleaning hasn't resolved.
Does it fit the Reefer 3XL 900?
No — the 3XL 900 uses a different part, R42486.
