That's great to hear! I'm glad the plants are perking up for you. Be careful with the ppm strength for autos. 500-650 is usually the max. If you are following a guide the numbers are typically for photoperiod plants which take a lot more than autos. Start at 50% strength and slowly ramp up from there. You can always add more but it's harder to fix when there is too much.
There's basically 3 big rules for coco:
1) Always fertigate - that's water + nutrients. Never water only.
2) pH 5.8-6.2
3) Always water to runoff. 20% of volume is a quick guide.
Success! Well, most of the time. Few tweaks here and there but that's the main bits.
Oh, which guide are you looking at?