Answer: Ideal TDS range: 50-150 ppm for most people. Here's the breakdown: 20 ppm: Not "too low" from purity standpoint - very safe. But long-term consumption (>6 months) may contribute to mineral deficiency if diet is also low in minerals. Children, elderly, pregnant women should avoid ultra-low TDS (<30 ppm) for extended periods. 150 ppm: Not "too high" - still very safe and well within WHO guidelines (<300 ppm). Provides good mineral content from water. Many find this range most palatable. Recommendation: Target 50-100 ppm for optimal balance. If you have balanced diet with vegetables, dairy, meat, ultra-low TDS (<30 ppm) is fine - you get minerals from food. If diet is limited or concerned about minerals, aim for 80-120 ppm. BIS (Bureau of Indian Standards) recommends <300 ppm for drinking water; WHO has no lower limit but suggests some mineral content is beneficial. The "perfect" TDS is personal based on taste preference, health status, and diet - anywhere in 50-150 ppm range is excellent.

Answer: Mineralizer cartridge is safer in most cases. Here's why: TDS Controller (Bypass method): Mixes pre-filtered water (sediment + carbon filtered, but NOT RO filtered) with pure RO output. Pros: Free/cheap (built-in), easily adjustable, quick TDS increase. Cons: Bypasses contaminants if input water quality is poor, not safe for bore water or untested water, requires clean municipal supply. Mineralizer Cartridge: Adds beneficial minerals (calcium, magnesium, potassium) to already-purified RO water. Pros: Safe regardless of input water quality, adds only clean minerals, no contamination risk, controlled mineral addition. Cons: Costs ₹400-₹1,500 for cartridge + installation, needs replacement every 12-18 months, less adjustable (fixed TDS increase). When to use which: Use TDS controller if: Municipal water supply (chlorinated, tested safe), input TDS 200-800 ppm, want adjustability, low budget. Use mineralizer if: Bore water or untested source, input TDS >1000 ppm, areas with known contamination (coastal, industrial), want maximum safety, have children/elderly at home. Best approach: If using TDS controller, test input water professionally first (₹1,000-₹3,000 for complete analysis). If any contamination detected (heavy metals, bacteria, nitrates), switch to mineralizer method only.

Answer: 250 ppm is NOT normal for RO system - investigate immediately. This indicates either: (1) Membrane failure (most likely): RO membrane should reduce TDS by 90-95%. If output is 250 ppm, membrane is severely compromised. Calculate rejection rate: if input is 500 ppm, rejection is only 50% (FAILED - should be >90%). (2) TDS controller set way too high: Possible but unlikely to reach 250 ppm unless input TDS is extremely high (>2000 ppm). DO NOT just reduce TDS controller! This treats symptom, not cause. Proper diagnostic: (a) Turn TDS controller to full MINIMUM (or bypass it completely); (b) Drain tank and refill; (c) Test output TDS with controller off - this is pure membrane performance; (d) If still >100 ppm with controller off, membrane has failed - replace urgently (₹1,500-₹4,000); (e) If drops to <50 ppm with controller off, membrane is OK - it was just controller set wrong - safe to adjust controller; (f) If between 50-100 ppm with controller off, membrane is aging - plan replacement within 6 months. Safety concern with 250 ppm output: If caused by membrane failure, contaminants (heavy metals, bacteria, chemicals) may be passing through. Stop drinking water until diagnosed. Use bottled water temporarily. 250 ppm won't immediately poison you, but long-term consumption of poorly filtered water defeats purpose of RO system.

Answer: Low TDS water (<30 ppm) is NOT dangerous for most healthy adults with balanced diet. The "mineral deficiency from RO water" fear is often exaggerated. Here's the science: Fact 1: Water is minor source of minerals. Even mineral-rich water (300 ppm) provides only 5-15% of daily mineral needs. 85-95% comes from food (vegetables, dairy, meat, grains). If you eat balanced diet, water TDS doesn't significantly impact mineral status. Fact 2: WHO position. WHO states low-mineral water does NOT cause deficiency in healthy people with adequate diet. However, WHO acknowledges very low TDS water may contribute to deficiency in specific populations: children with poor diet, elderly with low food intake, people with absorption issues, areas with diet already low in minerals. Fact 3: Possible long-term effects (debated). Some studies suggest ultra-low TDS water may: leach small amounts of minerals from body, alter electrolyte balance slightly, taste flat leading to reduced water consumption. Effects are subtle and long-term (>1 year). Practical recommendation: Healthy adults, balanced diet: <30 ppm RO water is perfectly safe. No need to increase TDS. Children, elderly, pregnant: Target 50-100 ppm for peace of mind. Install mineralizer (₹400-₹1,200). Vegetarian/limited diet: Consider 60-120 ppm range. Athletes, high sweat loss: Higher TDS (80-150 ppm) may help electrolyte replacement. Bottom line: Very low TDS water is safe. If concerned, add mineralizer to reach 50-100 ppm. But don't stress if drinking 20-30 ppm - just maintain good diet with vegetables, dairy, fruits, and you'll get all needed minerals from food.

Answer: Very bad idea - defeats entire purpose of RO purification! Here's why: Why some people try this: Misconception that RO "wastes water" (reject water) and "wastes membrane life". Logic: If I use more bypass (higher TDS controller), less water goes through membrane, less reject water, longer membrane life, save money. Why this is dangerous: (1) Contaminants bypass: TDS controller adds PRE-filtered water (not RO filtered). If you set it to achieve 200+ ppm output, you're bypassing 50-70% of water AROUND the RO membrane. This means heavy metals, bacteria, nitrates, fluoride, arsenic (whatever is in input water) are going into your drinking water. (2) Membrane failure undetected: With high bypass, you can't tell if membrane has failed. Output TDS stays high due to bypass, masking membrane problems. (3) False economy: You "save" ₹1,500 on membrane replacement but potentially expose family to contaminated water for months/years. Medical costs from waterborne illness far exceed savings. Reject water and membrane life facts: (a) Modern RO systems with good inlet pressure produce 40-60% purified water, 40-60% reject (not 90% waste as myth suggests). (b) Membrane life is determined by input water quality (TDS, hardness), not reject ratio. High bypass doesn't save membrane - replacing pre-filters regularly does. (c) Reject water can be reused for cleaning, plants, mopping - not "wasted". Correct approach: Set TDS controller for 50-150 ppm output maximum. Replace pre-filters every 6-12 months to extend membrane life (₹400-₹800). Replace membrane every 2-3 years as scheduled (₹1,500-₹4,000). Don't compromise water safety to save a few hundred rupees annually.

Answer: Some variation is normal (±10-20 ppm), but 40 to 90 ppm swing indicates a problem. Small variation is normal because: (1) Water temperature: Cold morning water flows slower through membrane, higher rejection (lower output TDS). Warmer afternoon water flows faster, slightly lower rejection (higher output TDS). Difference: ~10-15 ppm. (2) Inlet water pressure variation: Peak usage hours (morning, evening) may have lower municipal pressure. Lower pressure = slightly worse membrane performance. Difference: ~10-20 ppm. (3) Tank water age: First glass from freshly filled tank vs last glass from tank sitting 8 hours may differ slightly due to mineralizer contact time. Difference: ~5-10 ppm. Large variation (40 to 90 ppm) indicates: (1) Input water TDS varies dramatically: Municipal supply switches between sources (reservoir vs bore water). Test input TDS morning vs evening. If input varies 300 ppm to 800 ppm, output variation is expected. Solution: Install input water storage tank to buffer TDS swings. (2) TDS controller valve malfunction: Bypass valve sticking or pressure-dependent operation. Morning high pressure = less bypass (40 ppm). Evening low pressure = more bypass (90 ppm). Solution: Service/replace TDS controller valve (₹300-₹800). (3) Aging membrane with pressure-dependent performance: Worn membrane performs OK at high pressure (40 ppm morning) but poorly at low pressure (90 ppm evening). Solution: Replace membrane if >2.5 years old (₹1,500-₹4,000). (4) Booster pump cycling: If booster pump turns on/off based on tank level, pressure varies. When pump is running = lower output TDS. When pump is off = higher output TDS. Solution: Check pump operation, adjust pressure switch. What to do: Test input water TDS at different times. If input is stable but output varies >30 ppm, get professional diagnosis. Likely TDS controller or membrane issue.

Answer: Not necessarily defective - mineralizer performance depends on contact time and water flow rate. Why TDS increase may be less than expected: (1) Too fast flow rate: Mineralizers need contact time with water for minerals to dissolve. If water flows too fast through cartridge (high system pressure, large diameter tube), contact time is short, less minerals dissolve. Typical mineralizer needs ~30 seconds contact time for full mineral release. (2) Mineralizer capacity/size: Small inline mineralizers (₹400-₹600) increase TDS by 20-40 ppm only. Larger cartridge-style mineralizers (₹800-₹1,500) increase TDS by 50-100 ppm. Check specification of your specific model. (3) Needs flushing/activation: Brand new mineralizers sometimes need 2-3 full tank flushes to activate fully. Initial TDS increase may be low, then increases after few days of use. (4) Installation position: If installed on high-pressure line (before tank), water flows too fast. Better on low-pressure line (between tank and faucet) for more contact time. How to increase TDS from mineralizer: (a) Add flow restrictor: Small capillary tube that slows water flow through mineralizer, increasing contact time. Available from RO parts suppliers (₹50-₹150). (b) Upgrade to larger mineralizer: Replace small inline type with cartridge style in filter housing. More mineral stones = more TDS increase. (c) Install second mineralizer in series: Two mineralizers double the contact time and TDS increase. Simple but effective. (d) Check installation flow direction: Mineralizers have arrow showing flow direction. If installed backward, doesn't work properly. Is 25 ppm enough? 25 ppm is still very low but safer than 15 ppm for long-term use. Ideally target 50-100 ppm. If your current mineralizer can't achieve this, consider upgrading or adding second one in series.

Answer: These terms are often used interchangeably but have technical differences: 1. TDS Controller: Generic term for any mechanism that adjusts output TDS. Can refer to either bypass valve method or mineralizer method. "TDS Controller" on Kent/Livpure typically means bypass valve. 2. Blending Valve (Bypass Valve): Mechanical valve that mixes pre-filtered (non-RO) input water with pure RO output water. How it works: Takes water from line AFTER sediment/carbon filters but BEFORE RO membrane, and mixes it into output AFTER RO membrane. Adjustable: Yes - turn valve to control how much bypass water mixes in. Effect on TDS: Increases TDS by adding back minerals from input water (but also adds any contaminants that weren't removed by sediment/carbon filtration). Safety: Depends on input water quality - safe if municipal chlorinated water, unsafe if bore water or contaminated source. Cost: Usually built-in (₹0) or ₹200-₹800 to add aftermarket. Names: Also called "TDS Controller", "Bypass Valve", "Mixing Valve". 3. Mineralizer Cartridge: Post-RO filter cartridge containing natural mineral stones (calcium, magnesium, potassium carbonate). How it works: Pure RO water passes through mineral stones which slowly dissolve minerals into water. NO bypass of input water - only adds clean minerals. Adjustable: Not easily adjustable. Fixed TDS increase based on cartridge capacity. Some have flow restrictor to vary contact time slightly. Effect on TDS: Increases TDS by 30-100 ppm depending on cartridge size and contact time. Only adds beneficial minerals, no contaminants. Safety: Very safe - minerals are added AFTER RO purification. No contamination risk regardless of input water quality. Cost: ₹400-₹1,500 for cartridge, replacement every 12-18 months. Names: Also called "Alkaline Cartridge", "Remineralization Filter", "Mineral Cartridge". 4. Alkaline Mineralizer: Special type of mineralizer that not only adds minerals but also increases pH to 8-9 (alkaline water). Contains calcium carbonate, magnesium oxide which are alkaline. Summary - Which to choose? Want adjustable TDS, have safe municipal water: Blending valve. Want maximum safety, have bore water: Mineralizer cartridge. Want alkaline water benefits: Alkaline mineralizer. Don't want any adjustment: Pure RO (no controller or mineralizer).