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I'm LIVID right now. Been using this Pentair Rainbow chlorinator for 3 seasons now, and my pool has become a chemical nightmare. My CYA levels are through the roof - over 150 ppm! The chlorine is completely useless at this point. I've spent hundreds on shock treatments that do absolutely nothing. This thing is supposed to make pool maintenance easier, but it's just slowly destroying my investment. Anyone else experiencing this?

Oh wow, I feel your pain! I'm on my second cup of coffee just reading this. I had a similar issue last summer - my CYA crept up to 120 ppm before I realized what was happening. The Rainbow chlorinator uses trichlor tablets, which are packed with stabilizer (CYA). It's great for consistent chlorine release, but that CYA just builds up and builds up. Have you tried partial drain and refill? That's the only thing that worked for me, though it was a pain.

From a chemical perspective, this is actually a well-documented issue with trichlor-based chlorinators. The chemical formula for trichlor is C₃Cl₃N₃O₃ - each molecule contains cyanuric acid (CYA). For every 10 ppm of chlorine added, you're adding about 6 ppm of CYA. Over time, this accumulates since CYA doesn't evaporate or break down easily in sunlight. The Rainbow chlorinator isn't 'poisoning' your pool per se, but it's definitely causing CYA accumulation that renders chlorine ineffective. Have you tested your CYA regularly?

As someone who maintains a pool for post-workout recovery, I switched to liquid chlorine for this exact reason. The Rainbow chlorinator is convenient, but that CYA buildup is a killer. When CYA gets above 100 ppm, you need chlorine levels that would be unsafe for swimming to actually sanitize the water. It's like trying to lift weights with improper form - you're putting in effort but getting zero results. Have you considered switching to a saltwater system or liquid chlorine feeder?

**@PatioPrince48** I did a partial drain last week - drained about 1/3 of the pool. CYA dropped from 160 to around 110, but that's still way too high. I'm looking at another drain cycle, which means more water bills and more chemicals to rebalance everything. **@DeckDiver34** I test weekly with a Taylor test kit, but honestly, I didn't understand the CYA-chlorine relationship until it was too late. The pool store just kept selling me more shock. **@WaveRider30** I'm seriously considering a saltwater conversion now. This has been such a frustrating experience.

**@AquaAce** You're on the right track with draining. The formula is simple: if you drain X% of your water, you reduce CYA by X%. To get from 110 ppm to the ideal 30-50 ppm range, you'll need to replace about 60-70% of your water. I'd recommend doing it in stages to avoid stressing your vinyl liner. Also, stop using the Rainbow chlorinator immediately - switch to liquid chlorine or cal-hypo shock (which doesn't add CYA) while you're fixing this.

Ugh, the pool store trap! They did the same to me - kept selling me expensive shock treatments instead of explaining the real problem. I ended up switching to a combination approach: I use the Rainbow chlorinator early in the season when CYA is low, then switch to liquid chlorine mid-summer. It's more work, but it keeps my CYA in check. Also, pro tip: test CYA monthly during peak chlorinator use. That caffeine-like alertness helps catch problems early!

**@AquaAce** If you're considering saltwater, I can share my experience. The initial cost is higher, but maintenance is much simpler once it's installed. No more CYA issues, consistent chlorine production, and the water feels amazing after workouts. It's like switching from manual weight plates to a selectorized machine - more upfront investment but way better long-term results. Just make sure your equipment is compatible before making the jump.