Fish keep dying but parameters are normal

[kryan13]

I’m new to Reef2Reef but I’ve had a saltwater tank for a couple of years now. I don’t have an AIO tank so I can’t answer your question about water levels in various chambers. That said, you are correct that you should do weekly 10% water changes with salt water and that you should top off the tank/replace water lost through evaporation daily with fresh water.

When water evaporates it leaves behind the salt (and other minerals) so your salinity will rise unless you replace evaporated water with fresh. Weekly water changes with salt water help with nutrient export so your phosphates and nitrates don’t rise too much, replenishes trace elements consumed by tank inhabitants (though this is more of an issue if you have corals and I’m not sure whether you do), and allows you to maintain a steady salinity.

Does this help with next steps? What are your hopes for this tank?

Thanks! I guess I’m just not sure how to know how much fresh water to replace. Like, how do you know how much evaporated…just eye it? I would love to add another fish or two and some coral. I would mostly just like anything new to stay alive (all my original stuff - crabs and watchman gobie stay alive but anything new I add - fish, snails - dies after a couple weeks.

 

[Amelanchier]

I drew a line with a sharpie on the side of my tank at the water level back when i first filled my tank. You can do this now, just make sure your salinity is where you want it and draw the line where your water is. I manually top off daily to bring the water level back to that line. When I do a water change I first top off to the line, then do the water change, refilling the tank back to the line.

If I were you I’d run the tank the way it is now for at least a couple of weeks, checking parameters regularly just to make sure everything is staying in line now. Then I’d start trying to add things in again a couple of snails or a single fish at a time. Since it was taking two weeks for animals to die in the past, I’d wait at least three weeks to make sure the new inhabitants were doing well before adding in anything else.

good luck!