There are people with receptor and other problems of the thyroid that have NORMAL TSH but borderline or abnormal one or more of the following tests so you must have these checked:

Total T4 (TT4) AND Free T4 (FT4) Resin T3 Uptake (T3U/T7/T3RU) AND Free T3 (FT3) Reverse T3 (rT3) Thyroid Peroxidase Antibodies (TPOAb) Thryoglobulin Antibodies (TGB Ab) Thyroid-Stimulating Immunoglobins (TSI) AND TSH stimulating Antibodies (TSAb)

If you have negative to all the antibodies Thyroid Peroxidase,Thryoglobulin,Thyroid-Stimulating Immunoglobins AND TSH stimulating then I would supplement with iodine and selenium. You can do 150 mcg (micrograms) of selenium daily but iodine slowly increase. For example week 1 take daily 150 mcg (micrograms) of kelp (iodine), week 2 take 300 mcg daily, week 3 take daily 450 mcg, week 4 take daily 600 mcg. Most people without any antibodies to thyroid function (no sign of Hashimoto's autoimmune thyroid) will do well with 600 mcg to 1 gram (1000 micrograms) of kelp a day.

You should work with a functional/holistic practitioner who supports Paleo and can track and order the bloodwork/hormone panels. Do not try to do this yourself. You need help, but understand the science behind it.

Also read 2 books that cover iodine and selenium well:

Why Do I Still Have Thyroid Symptoms? When My Lab Tests Are Normal: A Revolutionary Breakthrough In Understanding Hashimoto's Disease and Hypothyroidism by Dr. Datis Kharrazian, DHSc, DC, MS, MNeuroSci, FAACP, DACBN, DABCN, DIBAK, CNS - chiropractic doctor

AND

Iodine: Why you need it, Why you can't live without it by Dr. David Brownstein, MD

Chris Kresser, a licensed acupuncturist, (also Paleo) has written a lot on thyroid/iodine, among many other topics on blogposts. He works with clients in his office and through Skype/phone.

I'm not sure on what the ideal balance is in terms of micrograms, but my understanding of selenium and iodine for thyroid health goes like this:

The enzyme that converts T4 to T3 (a "de-iodinase," since it removes one iodine) requires selenium to function properly. (So even if your TSH looks good and even your T4, if you're low on selenium, you likely wouldn't be able to convert to T3 very well.)