Yellow bottom fan leaves w/brown spots, plants losing smell and about 36 days in veg

had a slight root prob with algae growth in my reservoir using organic products so i got some canna cannazym and general hrdoponics calimagic and added them to the fox farm grow big and big bloom nute setup i already had running the week before (saw signs of nute burn after adding big bloom so cut all nutes for about 5 days) , 3 days after starting to use nutes again and my plants have yellow bottom fan leaves w/brown spots, plants leaves curling down and whole thing is just losing the dank smell it had before it was pruned and about 36 days in veg. Help is needed this is my first grow ...

Do you have a air stone in the res,also is it light tight,Has long has the mid section and the plant top look ok then you should be ok,most plant's will have the odd leaf turning yellow and falling of even in veg,don't panic and start adding this and that over something that might just be normal,if the plant has gone through a algae problem then it will take time to recover from it,has long has the res,is light tight and the nutes have air going to them then you should not get this problem again.Get some good air flow through the plant full stop.The brown spot's may be something has simple has just getting nutrients,on the leafs.Has for losing smell,i have never come across this problem before,so can't really answer,i have had plant's change smell like my jack herer smell's of mint during veg then go to a heavy hazy skunk smell in flower

No air stones just a simple air pump

put a air stone in the res,spaghetti tubing going to a air stone they make them in all different shapes now i have found the ball's to be better,if you can and you are not doing a grow like a nft
and are useing a medium then add a extra air ring to the bottom of the pot, with air been sent from a pump to the ring the plants will thank you for it,and you will have great white root's.By this i mean i do auto pot so i have a air stone in the bottom of the tank,sending air to the trays,but i still add a air ring to the bottom of the pots so the small film of nutrients the roots are sitting in has got plent of air going to it you can hear it bubbling,this is ideal,cost nothing to do but makes a big difference,even in soil grow's,i did my friend one not long ago in soil,just a air ring in bottom of pot then thin layer of clay balls,to cover the ring.Then just fill with soil add plant,have the air ring on 24/7,it increased his end result,and he had far fewer problems.Growing in auto pot's the medium coco / clay balls is just there for the first 7/12 days till the root's hit the bottom of the pot then the coco is just there to support the plants,all the feeding is done through the bottom,i never feed the coco after the first week or so

thanks will do any advice on the size i need to get?

hi , the higher the oxygen in the water the less chance of alge and root rot ect , and if u keep ur water temp around 19-22c convert for farnhite google ,, cooler water holds more oxygen ,

good luck