What would cause blue water?

[Floridafishy]

Tank had a 90% water change 4 days ago, to include new live sand and coquina shells to combat algae and yellowing water. New water with live sand and coquinas sat in a covered bucket for over a week prior to use in tank. Water was crystal clear until today; water is now blue. Minimal algae present around the lid, green-brown in color.

About 60% new water plus some old water and all the sand from before the water change are in the vase to the right, containing one tiny fish of same species. About 8 coquinas were added to improve water 2 days ago. Vase showed improvement in one day. No signs of blue.

The rest of the old water is in a bucket, no signs of blue.

The air hose got pinched the day before and was pinched for no more than 12 hours.

My only guess is somehow the air stone, which is practically new, is releasing blue dye for some reason after 3 weeks of use. What would turn the water blue?

Do I need to do another water change to save the fish from the unknown blue?

[farfromsea]

I don't have enough experience to answer why it would be blue but I would definitely change all of the water because I don't think it would be good for the fish. I would take the air stone out and put it in another container and check if it releases dye. Of course you need some air circulation in the tank so don't take it out I guess if that is the only thing providing circulation...

[mcgyvr]

Is the airstone blue? if so thats your answer..

[Ron Reefman]

It's been my experience that coquinas do not survive in an aquarium very well if at all. In the ocean they live in the edge of the water where they dig in the sand and are regularly exposed to the air. The few times I've put them in my tank (10+ years ago when I was starting in the hobby) they all died within a couple of weeks.

Sorry, I have no idea about the blue water. It may or may not be harmful, but since we don't know, I'd try changing it.

[Floridafishy]

farfromsea: The logical reply, thanks. I placed blue airstone in a small container with water; 10+ hours later, it's still clear.

mcgyver: Lots of other solutions remain, mine was only a guess. Hearing from others that may have experienced sudden dye release would be a better way to know with more certainty.

Ron Reefman: Thanks for the information. I originally looked up ways to clear water after I added coral like an idiot beginner and discovered coquinas remove toxins, so I thought I'd add in some for tank trial #2. We'll see how long they live.

Fish seem okay; starting the water change now.

[farfromsea]

Seems like if the air stone is blue like mcgyver said then that would be the culprit. Did you put the air stone in saltwater to see if the saltwater has some sort of reaction with it to cause it to leech blue?

How did the water change go?