I have seen too many smart and established reefers both have issues and report no issues with fish and LC. I feel that nobody should be posting that they have any idea of what is going on and everybody should at least post a quick warning like Dr. RHF did on page one. We are not talking about some thumb suckers new to the hobby posting about deaths or successes with the neighbor spraying for weeds, hand lotion crashing tanks, etc. It does appear that if you use a sock or some appropriate media to catch the flocculant, then there are minimal reported issues among hobbyists that you can trust. This is just too easy to implement, so why risk it?
As for corals, lowering too fast, too low or riding a roller coaster of stripping water down and then aragonite release back up is usually bad in the long term. Go slow and everything appears to be OK. I helped a local with a tank over 1.0 and he added 2 drops of raw LC (swimming pool stuff) a day down his overflow (which ended up in socks) - it took almost a year for him to get to .05 and nothing was harmed or damaged. Tanks don't just get to 1.0 overnight, so don't expect them to lower any faster.
GFO will bind to an equilibrium with the water and always leave something behind. LC will scavenge all that it can find. I would think that GFO is safer at low numbers than LC. However, I have not tried this.
If you want to keep things that don't care about higher po4 levels, then don't mess with it. There is some awesome self awareness and likely happiness in this. If you do want to keep some corals, sensitive inverts, microfauna, etc. that will suffer or die with higher po4 levels, then you have to do something. It is too bad that more do not understand what they want to keep long term and what is required to keep said things. If I had a softie, LPS tanks with a few stags, I would not chase any numbers at all, but that is not me. I do not QT fish, just long isolation/introduction in real reef tanks, so I rely on microfauna in the sand and rocks to eat/destroy tomonts when they fall off of fish... and these do not do well with higher po4 levels. I like my shrimp, cucumbers, snails, etc. to at least try and reproduce. Some of the acropora that I like to keep don't do well with hither po4 levels either, but I am not ever happy with just the acropora that don't seems to care about po4 at all, of which there are many.
Lastly, I have done some reading and it appears that LC is LC. There is no reason to waste money on a reef-based supplement when you can use swimming pool LC at a fraction of the cost. If anybody has any different information, then please post since I would love to know about it.
