Sodium - not getting enough rather than too much?

You are fine. I believe if I recall correctly that the amount you need in a day is about 500mg, but that would be averaged out so one low day is not a big deal. I can't imagine only having 200mg in a day I had 238mg in my breakfast and that was mostly from the Almond Milk and the All Bran Cereal.

Following potassium on MFP is pretty much a waste of time since I don't believe it is required on nutrition labels, so often even when it is present it is not reported. If you are really concerned add a banana, orange, lima beans, pinto beans, avocado, or lentil to your diet as they are all pretty high in potassium.

BTW, being low in sodium won't affect your weight loss except to maybe make it less likely you will retain water. It can, just like being low in potassium, cause feelings of muscle weakness and various other things as they are needed for the body to function properly. I am guessing you are getting plenty though as someone said if you are concerned your doctor can run a blood test to check your levels.

Following potassium on MFP is pretty much a waste of time since I don't believe it is required on nutrition labels, so often even when it is present it is not reported. If you are really concerned add a banana, orange, lima beans, pinto beans, avocado, or lentil to your diet as they are all pretty high in potassium.

I agree completely!! I was tracking potassium at first and thought OMG!! I was so low! Then I began to really watch it and realized that hardly any entries have it and packaged foods rarely list it. So I started looking it up in nutrition databases and found that I was never under the RDA. Now I don't track it.

But if you are worried, you can always chug a can of low sodium V8 which has over 1500 mg of potassium. Or in your case I guess you don't need to get low sodium.

I'm pretty sure you're getting more sodium than you think, since a number of the items on your food list don't have sodium listed. There's no way something called, "Rosemary & Sea Salt Thins" has 0 sodium.

Same goes for breads and even milks. They have SOME sodium.

The signs and symptoms of hyponatremia (low sodium) vary. The only way a doctor can confirm whether you have hyponatremia is by a blood test. Signs and symptoms of hyponatremia may include:

Drowsiness or fatigue
Nausea
Headache
Confusion
Restlessness
Loss of consciousness or coma
Hyponatremia treatments may include changing the amount of water you drink, or changing the amount of salt in your diet.

References; mayoclinic.com

I've also been struggling with reaching the 3500 mg mark for potassium and have been eating pounds of spinach, as well as bananas twice a day and potatoes. What did you do instead? What do you mean by 'started to really watch it'?

You could try a multivitamin or potassium supplement

Sodium is actually a very important part of your daily diet, to go as low as 300mg a day is dangerous. Your vital organs can start to fail with out the proper amount of sodium, no they are not going to fail over night, but in time all you are doing is damaging yourself.

I would achieve at-least 1,000mg a day and make that a must, if you can try to get 1,200-1,500mg a day. As for what salt you should be achieving this with, always go for sea-salt or himalayan salt. Never table salt, that stuff is literally as beneficial as going in your front lawn and using the dirt you have laying around as seasoning(I'm not joking).