A strong 600 GPD under-sink option — the Q3-600A alkaline variant is worth the extra $5
The Q3-600 delivers 600 GPD tankless filtration at a competitive price with a 4.9-star rating across 88 real-world reviews. The standard 7-stage model handles contaminant removal well. The Q3-600A adds inline alkaline remineralization for $5 more — the lowest cost to add remineralization we've seen on a tankless system. Unless you specifically want flat-TDS RO water, the Q3-600A is the easy pick. The main gap vs top competitors is certification depth — SimPure holds NSF 58 (RO membrane) but not NSF 42 or 401 that Waterdrop carries.
- 4.9 stars across 88 reviews — exceptional early rating
- 600 GPD — no-wait tankless output
- Q3-600A adds alkaline remineralization for just $5 more
- Touch panel with CF / RO filter life indicators
- NSF/ANSI 58 certified (SGS tested)
- 12% Awin commission — highest in the under-sink category
- Clean under-sink footprint, white design
✓ What we like
- NSF 58 only — no NSF 42 or 401 vs Waterdrop
- 88 reviews vs 1,000+ for Waterdrop G3P600
- SimPure is a newer brand — less name recognition
- Contaminant removal percentages not all published
✗ What to know
Specs at a Glance
| Spec | Q3-600 | Q3-600A |
|---|---|---|
| Price | $329.99 | $334.99 |
| Stages | 7 | 8 |
| Flow Rate | 600 GPD | 600 GPD |
| Tank | Tankless | Tankless |
| Remineralization | ✗ | ✓ ALK inline |
| Certification | NSF/ANSI 58 | NSF/ANSI 58 |
| Filter Indicators | ✓ Touch panel | ✓ Touch panel |
| Amazon Rating | 4.9 ★ (88) | 4.9 ★ (14) |
| Commission | 12% (Awin) | 12% (Awin) |
Q3-600 vs Q3-600A: Which to Buy
The $5 difference is the easiest decision in this review. For $5 the Q3-600A adds an 8th stage — an inline ALK remineralization filter mounted directly on the faucet line. That filter adds calcium and magnesium back to the RO-purified water, raising pH toward alkaline and restoring mineral taste that the RO membrane strips out.
The only reason to choose the standard Q3-600 over the A variant: you specifically want near-zero TDS output for applications where demineralized water matters — aquariums, certain lab uses, or steam irons. For everyday drinking water, cooking, and coffee, the Q3-600A is the better product at essentially the same price.
What It Removes
The 7-stage RO filtration process in both models covers the full contaminant spectrum:
- PP sediment (×2) — removes particulates, rust, and turbidity
- Carbon block — reduces chlorine, chloramines, and VOCs
- RO membrane — removes lead, arsenic, nitrates, fluoride, PFAS, chromium, heavy metals, and dissolved inorganics (NSF/ANSI 58 certified)
- GAC post-filter — final carbon polish for taste
- PP post-filter — final particulate guard before the faucet
- Q3-600A only — ALK inline filter — adds calcium and magnesium, raises pH
Both remove fluoride at the RO membrane stage. See our full guide: Does reverse osmosis remove fluoride?
How It Compares to the Competition
| Feature | Q3-600A ($335) | Waterdrop G3P600 ($299) | iSpring RCC7AK ($229) |
|---|---|---|---|
| Flow rate | 600 GPD | 600 GPD | 75 GPD (tank) |
| Tankless | ✓ | ✓ | ✗ (tank) |
| Remineralization | ✓ ALK | ✗ | ✓ AK stage |
| NSF 58 | ✓ | ✓ | WQA |
| NSF 42 / 401 | ✗ | ✓ | ✗ |
| Filter indicators | ✓ Touch | ✓ App | ✗ |
| Best for | Remineralized tankless | Max certifications | Budget + alkaline |
The Q3-600A is the only 600 GPD tankless system in this comparison that includes remineralization. The Waterdrop G3P600 has broader NSF certifications (42, 58, and 401 vs SimPure's 58 only) and a much larger review base. If certifications are the deciding factor, Waterdrop wins. If you want tankless speed plus alkaline water in one package at this price, the Q3-600A has no direct competitor.
Filter Replacement Schedule
The touch panel on both models monitors CF (carbon filter) and RO membrane life separately — one of the more useful features at this price point since you don't need to track replacement dates manually.
- PP sediment filters: every 6–12 months depending on source water turbidity
- Carbon block: every 12 months
- RO membrane: every 24–36 months
- GAC / PP post-filters: every 12 months
- Q3-600A ALK inline filter: every 6–12 months
SimPure sells replacement filter kits through their site and on Amazon. Annual filter cost runs roughly $60–90 depending on water quality and which stages need replacing in a given year.
Who Should Buy the Q3-600
Good fit if: you want a 600 GPD tankless under-sink system, you'd like alkaline remineralization included (Q3-600A), or you want the SimPure brand's 12% affiliate commission and strong early ratings.
Consider Waterdrop G3P600 instead if: NSF 42 and 401 certifications matter to you, or you want a brand with a longer track record and 1,000+ reviews.
Consider iSpring RCC7AK instead if: budget is the priority — the RCC7AK delivers alkaline RO at $229 with a tank system and WQA certification.