Help and thoughts

[Printerhands]

So I just started my 29g two weeks ago and this past Tuesday I had put my first plants in. And I have noticed that they are yellowing at the edges and are getting dead spots on the leaves. I have determined that the is a potassium deficiency. So I ordered some flourish potassium and should arrive today. My setup goes as follows: a substrate heater cable, 20lbs of sand, 20lbs of Eco-complete, and topped off with 10 lbs of sand. I have a basic CO2 injector going and also a submersible heater. The water temp is at about 75 and last nite I tested the waters and PH 7.6, ammonia .25 nitrate 80ppm and nitrite 5.0. The water was slippery and I also did about 20% WC. I have been dosing flourish and flourish iron and using seachem prime. The plants I have now are crypts and I'm getting more in today through mail along with flourish potassium. Here are pictures of the plants and any thoughts would be helpful.
Thanks

 

[Billbug68]

Crypts tend to melt when moved or replanted, this may be what you're seeing. Even though you're using Eco, they still will appreciate root tabs as well.

 

[Printerhands]

Crypts tend to melt when moved or replanted, this may be what you're seeing. Even though you're using Eco, they still will appreciate root tabs as well.

Alright sounds good. I did order some root tabs and should be here next week. Hopefully they can deal tell then. And I got my potassium in today but no new plants.