Without knowing what was used to dye the coral blue, I would hold off on putting it in the tank. Assuming that bleaching was all that was done to the white pieces, they should be safe to add to your tank. HTH
Adding to the above questions, how long of a time period are we talking about here...over a few days? I've had my xenia shrivel up for a few days from toying with the current flow and direction. It returned to it's original condition a fews days later. You may have just shocked it by moving it.
I've used the kalk/hypodermic needle method on aiptasia in my early reefing years. Good luck talking the drugstore into giving them to you...I've tried, you need a perscription to get anything needle related from them. If you don't know anyone inside the medical profession, your best bet is...
I use two seven gallon aquatainers (camping drinking water tanks. They have an on/off spigot making it easy to fill directly into the sump. They're not too heavy to move around when full and are relatively cheap ($7-$8). I have kept pre-mixed water for well over a month with no adverse...
I don't think legthening the pipe will create any adverse conditions for this particular skimmer. Keep in mind that the remora is not a venturi or traditional downdraft skimmer so "chopped" air will not be pumped up the inlet pipe. Where I can see this increasing the bubble size...
I can think of two options here...1) Run the water level in your sump high. I wouldn't do this one since any power outage might overflow it. 2) Fabricate a base to stand the skimmer on in the sump, extend the tube your powerhead attaches to so it is fully submerged again, and (optional) extend...
Since Limestone is primarily composed of calcite and is essentially calcium carbonate (CaCO3), it should be no harm in adding it to your tank (considering Limestone is ancient sea floor). The aragonite reef sand many reefers use is a polymorph of calcite (same chemistry, different structure).
