Color of leaves

Go with what 0011.. wrote.

you overwatered. you dont water SOIL daily !!!! SOIL needs wet/dry cycle for roots to get oxygen. now you have magnesium problems. ph is most important if you grow in soil, you MUST adjust it to 6.2-6.5 value.

Get the strips. The ph-probes require constant buying of stock solutions to callibrate it and even to store it. the probe gets scratched or damage, it's trash. I've used about 20-30 strips out of hundred in 3 years, lol. Spending 6-7 dollars every 5 years or more is much cheaper than a ph-pen. get the .5-reso / 4-color strips and it's easy to assess. Always water entire substrate, and don't leave dry pockets. Wait for top 1" to dry and repeat. simple as that. Don't deviate. A little runoff is fine, and over time you can dial that in to minimize leaching of your pre-amended nutes in the FFOF soil. If you need to dilute the substrates concentration of nutes, that's when you want to get some purposeful runoff. FFOF is known to be a hot soil. if you have been fertilizing before it is needed, you made it even hotter. You probably don't need to feed for 6 weeks or so, maybe up to 8 weeks in some cases. i'd wait for a hint of yellowing at bottom of the plant before starting to ramp up fertilization. Even then don't start at full, maybe 1/4 or 1/2 depending on the state of the plant. So, what you see is more likely due to overfeeding than underfeeding given the information above. I wouldn't overreact unless it starts to progress fast. Just stick to water-only for a bit. I wouldn't even try to get extra runoff at this point. How you react should be about the rate of progression and confidence in the diagnosis. Also, adding more is much easier than taking excess away, so always be confident before adding "more," if you continue to use FFOF, make a note of when the plant needed supplementation so you can pre-emptively provide it without the symptom showing next time. soil pH is good around 6.5-6.8.