Is my ph meter is the problem or the water. Im using ro water but i adding silica force xpert about 2ml for 10litre water for just buffer.After that i stir

That actually sounds pretty normal to me not necessarily a broken meter. What you’re describing (pH slowly drifting down after 30–60 seconds) is something you often see, especially in nutrient solutions. When you stir, oxygen gets in and CO₂ exchange starts happening, which can slightly shift the pH. Also, nutrients themselves can keep reacting in the water for a bit, causing that slow drop. A few things to check to be sure everything is fine: Make sure your meter is calibrated regularly (at least every 1–2 weeks) Clean the probe gently, deposits can affect stability Always measure after letting the solution sit for a few minutes (which you already do 👍 Temperature differences can also cause slight drift A fluctuation of about 0.1 is totally acceptable and nothing to worry about. If the value keeps drifting continuously or jumps around a lot, then I’d suspect the probe. But a slow drop like you describe is usually just normal solution behavior, not a broken device. So in short: your meter is most likely fine 👍 Injoy your Grow.

bro steady stimming but this is a ditchweed take ................"I haven't spot-checked my pH in 4-5 years, bwahah. Good soilless/hydro nutes don't drift." ph drifting is the number one tool that hydrotek uses to hit the absorption about the entire chart, past that, when your plants drink in ratios commensurate to the cultivar, the environment, and so on...so at some point, theyll be uptaking water more than nutes for example...again causing drift. dude is applying the trump method for covid testing to his plants water lol, if he doesnt test then there is no issue bro your issue with the silica is your time frame. ten minutes for silica to bond with water is not it. idk if someone on here told you that, or chat, or a bottle....but the common forms of silica delivery would be more on the scale of '1 hour' for a quick and sloppy/dirty whip up of quick nutes and a '24 hour' to assume full bonding. you can help yourself by mixing better. a food grade auger bit and a corded drill and time. really hope you figure this one out before following some of the other advice here. "stop testing your water ever" "add other salts that you never add before silica" and more lol

There are several things you need to know, the first is that the silica must be added first and then the rest of the fertilizers and it is normal that it makes the pH fluctuate, the second I recommend that you always cut the water with half of that of the tap . Buy a nice submersible pump to turn the water

I used a silica supplement in the past, it was 1 ml/L recommended dose. It dropped my water to PH 4.0 from 7.0 so what I did was mix silica 1st give a good stir and then added PH Up to get to a PH of 6.0 before adding any other nutes. The bottle recommended mixing nutes in that order.

Because there’s no Calcium carbonate (CaCO3) and no Magnesium carbonate (MgCO3) in your RO water to stabilize your pH… RO process strips out the calcium and magnesium that provide this stability.

heck, just get the 4-color strips and be happy with .5 pH resolution, it's good enough and probably cheaper / less hassle over time. Once you have stuff measured out to balance the pH, it's not going to change if you use the same fertilizers and same RO water. there's a callibration process. Check your manual. Ensure that is not the problem, first. If it swings drastically, there's a lack of pH buffer. If this is soilless/hydro context, i'd strongly consider a different fertilizer if the pH is swinging all over the place. What green claws mentions is worth looking into, too. check you manual. Even the cheapies adjust for temperature but it's possible it doesn't and then anything that deviates from i believe a default of 25C needs to be calculated/adjusted for temperature. You can google that math. forever buying callibration fluid and having to store the device properly is a pain in the ass. buy a 100-pack of pH strips and just spot check, occasionally. Like i said, if it's a soilless/hydro context good products will result in consistent pH. If it's a soil fertilizer, your rootzone biome will help regulate pH. Check runoff of soil to guesstimate how that's working out. Be a bit forgiving with runoff readings... it will never be 100% representative of the medium. learn what 'normal' is then only worry if it's progressing in either direction over time. I haven't spot-checked my pH in 4-5 years, bwahah. Good soilless/hydro nutes don't drift.

Also if there's no temperature on the pen it won't ever give an accurate reading.

Hi. If you have a temu pH pen it's probably that what needs calibrating. This is why I went to living soil. Hate pH pens, if you want to do a proper job of it buy blue lab pH pen, there truncheon for ec levels are cool and never need calibration.. Good luck