Brownish leaves in the centre veins?

Hey there! It sounds like you're having a bit of trouble with your grow, but don't sweat it, happens to the best of us! So, you're thinking it might be a pH issue, but you don't have a kit to check it. No worries, we'll try to figure it out. First off, you mentioned the roots touching metal, but you removed the homemade air stone, so that shouldn't be the problem anymore. Since you're using fresh feed and water with Advanced Nutrients, it's unlikely to be a nutrient issue unless you've made some big changes lately. Without being able to test the pH, we'll have to rely on observing your plants. Keep an eye out for any signs of trouble like yellowing leaves, curling, or spotting. That can give us clues about what's going on. For now, try using distilled water if you can, and don't overfeed your plants. Also, if you're using tap water, let it sit for a day or two to let the chlorine dissipate. If things don't improve or get worse, it might be worth investing in a pH testing kit. Keeping the pH in check is super important for your plants' health, so having the means to monitor it is a good idea.

growdiaries.com/diaries/197639-seedsman-peyote-wi-fi-cbd-2-1-grow-journal-by-techdco I grew this strain before it did really well for me but always looked a bit hurt and was colourful on the leaves in late veg and early flower. I would check your lighting as well. 400W at 45" seems ok, but I don't know your light it might be getting to much. Curling leaves is sign of heat or light stress from my experience. And that coloration on the leaves looks more like PH issues to me then Calcium, the feed your using has 3% Ca and N. Maybe it needs more, I'm not to speclized in hydro growing. https://www.advancednutrients.com/products/ph-perfect-sensi-grow-bloom/

Looks like calcium is needed like others have mentioned. Add some at the bottles recomended dose.

the roots touching or not touching metal will make no difference whatsoever . for having no ph testing capability its looking remarkably healthy A weekly calcium/magnesium supplement wouldnt go astray Good luck mate 👍

Es el principio de una deficiencia de calcio. Agregue una dosis más grande de calcio a la solución nutriva.

Calcium deficiency. Nothing to do with touching metal.