Purple underside leaves and stem on tomato seedling
I am almost 2 weeks into growing my cherry tomato seedlings in hydro. In the pictures they're different sizes because some of them were planted between 5-10 days apart from one another. However, the oldest one which has the most leaves, seems to have its leaf tips curled upwards and the underside now is completely purple! I have been giving them seedling/cutting part A+B nutrients by DNF. Ive been given them only 1/4 strength, and the NPK on the bottle shows 2-0-2 on A and 0-1-3 on B. I also adjust the pH downwards everyday using apple cidar vinegar.
I did some research and the only problem i found associated to this was a phosphorus deficiency. I've posted some pics, i hope someone can give me an answer or solution. I was thinking just add a little bit more of solution B to increase phosphorus, but that will also increase potassium as well, so before i start playing with nutes I thought id get some advice from you guys first on what to do. and yes this is my first grow in hydro lol a little more about the setup...
5 - 16watt daylight CFL's (will be adding alot more and higher wattage when these guys get a bit bigger, have y apapters coming in atm)
ebb&flow system, 2.5 gallon reservoir.
if you need more info, let me know.