"Kelp stimulates the thyroid gland in iodine-deficient thyroid disease. Excess kelp causes hyperthyroid conditions, including a rapid heartbeat, sweating and nervousness."
This indicates to me kelp is probably not something you need, which is why I suggest alfalfa.
Alfalfa is an accumulator, just like kelp, but are chemically different. Alfalfa *may* contain iodine, depending on where/how it's grown, but typically in nowhere near the concentrations as kelp. If you think you need iodine, try iodoral or lugol's. My guess is you really need selenium as well, of which alfalfa *can* be a good source, again depending on where/how it's grown. I would try that and possibly barley grass as well.
In short, drop the kelp, take lugol's, selenium, and try the grasses or even spirulina to fill the gaps with phytonutrients.