Supersoil Grow Help!!

Hey RIU community, long time reader first time action taker. I appreciate all the information this website has provided me and would like to first off say thank you to everyone who posts, replies, and works with one another on behalf of a common passion. The knowledge I have gained from reading thread after thread has not only been eye opening, but extremely fun!

Now to the business at hand. I currently have 4 plants in Subcool's supersoil and they are approximately 2 weeks into flower. The other day when I went to look at them I noticed that one of the growth tops was withered and hanging limp from the plant. I immediately started to investigate, but there seemed to be too many potential problems so I waited a few days and now 3 out of the 4 plants have almost golden or burnt looking leaf tips. I also noticed purple lines running up the stems. The problem seems to be spreading fairly rapidly. My fan leaves have always been a very rich dark green so my immediate thought was nitrogen toxicity. I have only been using the Supersoil and tap water, no additional nutrients or fertilizer. My main concern is if it were nitrogen toxicity wouldn't this have shown up before? Temperatures are on the low side, but the plants have shown no adverse effects to this point so I don't believe they are the issue. Also the damage is occurring on parts of the plant that are much further away from my lights (approx 200 actual watts cfl, not equivalent) than other areas that are unaffected. The plants are from bagseed, but based on plant characteristics I believe that the three effected are all sativas' while the one plant unaffected is a indica. Let me know if you need any more information. I will attach some pictures and would really appreciate any help you may have. Stay up .

How much super soil did you put into your pots? Sometimes I see a burn on plants in SS for abit but once they get used to it they start rockin! Also how well did u mix it? If there is a pocket of amendments that didn't get mixed well it can burn roots!

You may have overwatered. That will kill em dead as doorknobs

I filled 5 gallon pots a little less than halfway with the super soil. I did mix it, but not as well as I probably should have looking back on it. I was thinking possible root binding because of the spotty damage, but that makes a lot of sense that hot spots in the soil could be effecting specific roots or groups of roots as well.

I am fairly confident that it is not overwatering, however because I have been letting the pots dry out really well before I re-water. The damage actually showed up right before I was due to water the plants and the soil was very dry, probably a little too dry in all honesty.

I'd say that your soil is a bit hot but nothing really to worry about.. I have see quite a few people get their plants burned from this supersoil.. And I'm not at all talking bad about it, just think people should cut it with some plain soil

alright I really appreciate the feedback fellas. Max I saw you posting a lot on a previous Supersoil post so I appreciate the feedback in my situation. Hopefully the plants will be able to power through. Its been a crazy ride so far so lets hope this is just another speed-bump along the way.

Any thoughts as to why its only happening to the one strain and not all of my plants. Also is it possible that this is a lack of nutrients? My initial thought was burn as well, but Subcool posted in his thread regarding the soil that if you don't use 7 gallon containers you may need to top dress later down the road. The dark foliage and leaf tips have me thinking overload, but just figured I'd check all possibilities.