Hydro - Ec Variations - how do you deal with them ? What the hell is going on in my soup ?

while some molecules are too large to fit in through roots, the plant itself does not select what it uptkes... if it is in solution, it's coming in. You have hydro nutes, so these are all chelated/fixated/ready to be used by plant. It's all getting absorbed in this context. So, evaporation can cause a rise in EC. If soilless, as long as you get a healthy runoff (at least 10%) you should avoid any climbing EC levels. In hydro, you simply can add a proportional amount of ph'd water to fix your EC level. Your meter's error% could cause fluctuation in data collected that is not tied to any change in the water or substrate. is it also supposed to be measured at 25C? i cannot recall if that impacts measurement of EC or not... the equipment's error should be considered, if necessary. for the pH .. it's a bit concerning.. it should not shift unless microbes are causing it... evaporation will cause it to rise, but this should not be a significant amount lost to evaporation if done righ. pH is the balance of h30+ and oh- in solution... that determins acid v base, then strength is about molarity, or how much per volume... evaporation will increase whichever way it is leaning on pH scale, but like i said above, you should be limiting how much evaporation is occuring and therefore it should not be a major factor in pH swings. Microbes are the thing to worry about. they'll eat your nutes and evacuate different molecules that may be result in a different pH than before.... and they continue to do so, so it adds up quickly over time. if you aren't going below 5.8 i wouldn't worry. Good hydro nutes should be buffered. If you find swings common, try a different brand (assumes you can rule out microbial causes) Regardless of what the peanut gallery says, i would never let pH drop below 5.8. I'd stick to 6-6.2 as it is better for calcium and another molecule or two to avoid 5.8 and below. EC is easier to keep consistent.. you control the mix. If your rez is covered, should avoid effects of evaporation. A little increase due to evaporation is nothign to worry about.. if it is not minimized, you may want to find ways to reduce the rate of evaporation (like a covered rez). You should always worry about pH .. and EC. Small changes are no problem. Observe and react to plant to find those thresholds and act premeptively in future. Environment and genetics will cuase fluctuation of what a plant can and cannot handle. there is no 1 answer. If you are being careful, i'd keep eye on it but if it keeps oscillating in same small range, i'd chalk it up to equipment precision.