Don't post much though I wanted to share some thoughts pertaining to the unknown. I've asked this question in different ways over the past 5 years in different forums as well as searched for information with out much help. Like a lot of you I've been reefing for over 20 years now with great succes though we moved to Florida over 5 years ago and since they we have noticed issues since we have our own well and have a whole house RO then our reef water goes through a reef RO/RI to product 0 TDS (standard pratice for successful reef keeping). Since we moved we've set up a few different reef tanks over the years with no difference in husbandry then any of our others but have had barely any success growing corals worth measuring like we used to. We've come to the concusion there is something that can not be seen in our water that could be pathogens, other metals or carcinogens we can not measure since we are not testing for them simply put. I've recently seen a video stating there is other things in water that has 0 TDS.
If this is a plasuable issue we have, this means we are not alone and there are other things that we all should be testing for beyond 0 TDS, this could be a reason in which some have success while other do not. Taking it a step further imagine if this is true and you keep adding the same top off water that has this 0 tds but you continuing adding these other harmful substances. If your corals are not uptaking them its only increasing the concentrations and making things worse. Pretty much this is what we have seen and why our system does actually get better with larger water changes.
IMHO its possibly the holy grail of reef keep that no one knows about or wants to address since 0 TDS may not be a bar to reach thinking all is fine.
If this is a plasuable issue we have, this means we are not alone and there are other things that we all should be testing for beyond 0 TDS, this could be a reason in which some have success while other do not. Taking it a step further imagine if this is true and you keep adding the same top off water that has this 0 tds but you continuing adding these other harmful substances. If your corals are not uptaking them its only increasing the concentrations and making things worse. Pretty much this is what we have seen and why our system does actually get better with larger water changes.
IMHO its possibly the holy grail of reef keep that no one knows about or wants to address since 0 TDS may not be a bar to reach thinking all is fine.