Yugang Reactor Help

[renesis]

Hey guys, needing some expert insight on my 90P build regarding the Yugang reactor . I’d like a sanity check on sizing.

System

• Display: 90 × 45 cm outside, 10 mm glass, so ~88 × 43 cm inside (~3,780 cm²), rimless, lidless.
• Sump: 20-gallon long (76 × 30 cm, ~2,280 cm²), 3 chambers, loose lid.
• About 220 L total water.
• Return enters below the surface; no deliberate surface agitation.
• BeanAnimal overflow, with the main draining underwater (no cascade).
• Currently cycling on tap water: KH 13, GH 12. The plan is RO remineralised to KH 3–4.

Reactor

• Horizontal Yugang, 3" Sch40 PVC (ID 77.9 mm), 46 cm long.
• Outlet rotated to near the limit of what my plumbing allows, so the pocket is much smaller than half-full.
• CO₂ flow meter at about 9 mL/min. That’s slightly over what it dissolves, so it gives small occasional burps.

What I measured

• Plateau: pH 6.80 at KH 13 ~ 60 ppm (pH/KH estimate). Degassed baseline pH at 8.2.
• Overnight decay after CO₂ off: k ≈ 0.12/h (half-life ~5.7 h). That implies a CO₂ exchange rate of ~4–7 cm/h, i.e. a calm surface.
• Working the 1/17.7 rule backwards from my reactor area (~180–358 cm² depending on rotation), my effective loss area is ~1,100–2,200 cm², against ~6,060 cm² of real water surface (display + sump).

Am I just way off on my surface agitation? I have mild ripples, but nothing overly agitating, but even without taking the sump into account, I should be seeing way more loss right? I'm planning on keeping neocaridina, so aiming for a 30-40ppm max, but even on my min setting I see ~55-60 ppm.



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