Oh. I forgot, but I meant to reply to the comment by keith_r.
You are correct that they are detrivores, which means they eat tiny little morsels of deteriorating plant and animal proteins, teeming with bacteria and zooplankton, laying on or bouncing along the bottom. They are benthic feeders and benthic dwellers. Do not use PVC drops for Redclaw habitat or stack any habitat up for them to dwell in, as they do not make anywhere near efficient use of them, waste their energy pushing them around and they are not naturally high-rise apartment dwellers. Properly designed Cherax habitat is available on the net, and truly is more than worth the extra expense. Over the decades of its useful life it will pay back thousands of times its cost in increased survival rates and production.
Next "iodide" is a negative ionic oxide of iodine of the first order, as such they are fairly unstable and easily enter into other chemical reactions. Due to this Iodide compounds are normally used to add into feeds and foodstuffs for terrestrial animals to guard against iodine deficiency, which is destructive of the ability of the thyroid to control metabolism, often resulting in mental retardation.
Normally, sufficient iodine is naturally present in most seafoods in generally greater percentages than in terrestrial animals, because these oxides are water soluble, washing out of our soils and into our waters. It is highly unlikely that you will ever see a Redclaw deficient in iodine, tho' it is possible.
What you will see is Redclaw, or any other crustacean, which are deficient in Calcium, which is what they use to quickly harden their carapace, or exoskeleton, immediately after moulting.
I am always happy to help anyone who wants to do successful aquaculture, if you contact me.