what are the best type? My husband has just purchased some which seem to say both sodium selenite and selenite, 100 ug,, not sure if is the correct compound. The instructions are in small Turkish language/ print n fortunately. Any comments?
had not noticed autocorrect must have worked paper stuck on label to what infact might be Polish says both selenite and selenate, thus my query!
Some here will probably disagree with me, but Sodium Selenite is the right one to buy. I use that, and it works for me. I proved it via my usual digestion test! If I start getting reflux, then it's not the right one. I have low stomach acid so rely on getting the right forms of supplements or else symptoms rapidly return. I take 200 mcg daily. You might want to build up to that amount.
You should retest selenium levels
That’s a high dose to take everyday indefinitely
I take your point, but without it I get reflux after a couple of days. Same if I stop or lower Iodine or Molybdenum.
I suggest you have a read of the link below. It is to a USA site so some details might need to be adjusted so as to apply in the UK.
Selenium
Fact Sheet for Health Professionals
This was the supplement recommended by the late, great SeasideSusie :
She wrote a reply to another member on the subject. Do a search for "Susie" in this thread :
healthunlocked.com/thyroidu...
Using the link should take you to the right reply but the forum has a recurring bug which means it often won't do that, so you'll have to find it yourself within that thread. 
Anything between 100-200 units daily, I usually selenium L methionine, I think that's the type of selenium. It's good to have levels of selenium tested first. Mine were over range with no supplementation
Advice on supplements & iron panel and selenium /zinc tests
Selenium supplements for hypothyroid
SELENIUM SUPPLEMENT HELP
Goitre & supplementing selenium & iodine 
selenium supplement
