Accomplished my 30 gallon water change (weekly). Question- Would like to know how many mls of trace I need to add at the w/c- using Greg's Plantex CSM + Boron at 1 tsp per 167 mls. Is this set to establish a certain iron level? Didn't see in the EI what the desired level of iron @ w/c should be. My seeing eye dog needs a day off once in a while!