Help needed ASAP

Came into a few problems last days my plants stems started turning really red, leafs started becoming discolored and crimpled, I'm suspecting its probably a PH problem but not sure, never had this happen before in my previous grows

currently I have 3 units and this has only affected one unit and i've treated them all the same so i can't quite figure out what is wrong with this one. my tempretures are spot on between 25C-29C, and my nutrient mixes are spot on and my humidity are fine so i've ruled them out as the problems

any help is appreciated It pains me to see them like this!
thanks!
-sumbadazzbud

Not certain but looks to me like a phosphorus (P) deficiency. Make sure pH is below 7 but above 5.5 (I can't tell if you're using soil/soil -less or hydro, adjust pH accordingly in that range) If you have an excess of iron (Fe) and zinc (Zn) they can make phosphates unavailable. Hope that helps.

oh yah, sorry. I'm using amazon aeroponics unit, it has a reservior, i've got 3 of them, each with 7 plants in, but this unit is the only unit that has been effected, and i've been giving them the same feed, I did notice i have a small algae buildup(the green floating on the water type) but I don't think that can have these types of effects on the plants.

I don't know really, on my 1st hydro setup, always did soil/soil-less before though I would speculate algae might reduce available O2 and would likely affect pH. If all the units feed from one reservoir that's unlikely though... How do your roots look? Same color and such as the other units?

Reservoirs are seperate, roots are shiny white

Separate reservoirs? Check the pH of the affected one, the algae could result in a more alkaline solution and possibly induce nute lock-out. You need to get rid of the algae regardless of course as it will clog pumps, filters, air lines, etc. Below is a pic I got from somewhere (maybe here), does it describe your situation?

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