How hard is too hard for tap water

Around 300-500+, "they" say you should think about filtering. I have 300ish (from local water quality report) and do not filter. Is good enough for me. Heck, i even started using soft water due to ease of access and higher GPM rate from that spigot, lol... even "soft" water is fine... maybe not for a "mother" plant you keep for years, but any single grow cycle is definitely not a problem. It might mean that you may need a little less Ca or S than someone else... Still have to observe and adjust based on what you see in the plant, regardless. I'd trust your quality report over a "TDS" pen. It's just a conversion of EC. A cheap TDS pen cannot measure ppm accurately. it measures EC and converts it with a factor that will vary by brand/company/region. The fact you might have 3 unique conversion factors should be enough to explain why it's not accurate, lol. Below is a copy and paste of 3 different ways EC is converted to PPM on these devices " US EC Meter: 1 EC = 0.5 PPM European or International EC Meter: 1 EC = 0.64 PPM Australian EC Meter: 1 EC = 0.7 PPM Knowing this, we can derive these 3 EC to PPM conversion formulas: US EC Meter: PPM = EC × 0.5 European or International EC Meter: PPM = EC × 0.64 Australian EC Meter: PPM = EC × 0.7 " from: https://waternitylab.com/ec-to-ppm-conversion/ Again, these TDS pen ppm values are basically trash. It's an okay ballpark number, but it is not super accurate. i'd trust your water report more than the "300" reading. ---- About chlorine.. first, if your area uses chloramine, leaving it out does nothing. Chloramine will not gas off easily - especially over 24-48 hours... beyond a doubt useless. Second, the levels of chlorine are so low in city water that it is nothing to be concerend about. A plant actually uses "some" chlorine (a trace element), so a little bit is useful. Stagnating water for 24-48hours provides little to no benefit and actually elevates risk of problems if some nasty microbe grows in it during that time. There's no reason to let irrigation water sit out for a day or longer. Also, don't use rainwater thinking "natural is better" - just to clear up a similar myth involving your water. Rain water is just adding all the pollution from your area which likely includes some heavy metals, lol, or screwing up the pH with acid rain etc.