Whats Happening!!!

[chickenhousekey]

Hey all, I've been in the hobby now for about 3 months, got about 100 or so pounds of live/dry rock, 2" sandbed, and cycled my tank for 6 weeks , I have a 75 gallon Reef display with a 90 gallon sump all water parameters were in check so I was doing a weekly water change, within 3 days pretty much all my fish had gone belly up, and one cleaner shrimp... I did a 50% water change to hopefully correct whatever had fluctuated, after the water change I checked water parameters again and they were out by alot! Worried for my other fish and corals! Any tips on why this would have happened so suddenly, and how to prevent this?

Also I was adding some salt directly into my display tank bit by bit to get my salinity levels back up after the big water change and all my corals seem to be doing fine except for half of my green star polyps, and my green brain still haven't opened back up, kinda worried I may have really stressed them out and that they may not open back up again?

Calcium - 360ppm
Carbonate Hardness - 125.3ppm
Phosphates - 0.25ppm
ph - 7.6ppm
High range pH - 8.2ppm
Ammonia - 0.25ppm
Nitrite - 0ppm
Nitrates - 10ppm

Cheers

 

[Sk8r]

You sure that 'carbonate hardness' reading isn't your salinity?
Here are some useful things to know: salinity can drop a distance and not hurt anything. A RISE in salinity greater than .002 per 15 minutes is pushing safety. Best go slower: that can be lethal.
Salt crystals can burn fish gills or coral flesh. If you need to raise salinity top off with salt water.
Your ph is a shade low, indicating your dkh alk may not be good. Keep dkh between 7.9 and 9: 8.3 is a nice reading.
That ammonia level can harm fish.
That phosphate level can harm corals.
Your nitrates are not that bad.

 

[bertoni]

[welcome]
I agree that most of those numbers are acceptable. The phosphate and ammonia levels could be a concern. I'd get a second opinion on the ammonia kit. They often seem to fail and read ammonia everywhere.

I agree that adding salt directly to a tank is more likely to harm than help. Simply replacing any evaporation with saltwater instead of RO/DI for a while usually will raise the salinity of a system quickly enough to avoid problems without causing rapid spikes.

 

[ColoReefer970]

Have you tested your fresh mixed water?

Adding salt to the tank directly is not good...

A 50% water change with "needs more salt" water can shift things significantly...

Testing your tank and your new water at the same time you can match them even if your instruments are off or you drip fatter drops than everyone else...

I had a bucket of salt that mixed up to 5.6 dkh when the label promised 7.5....a 50% water change without adjusting that would significantly lower my dkh... and most people would just walk away thinking "fresh water, we're good for a week!" Then wonder why dkh took such a dive a week later and start chasing the wrong end of the problem

 

[Reefiez]

I want to say that your fishes could have died from ammonia...

How many fishes did you add in 1 go? New reefers (like me) tend to get super excited and overstock their tank initially. The nitrifying bacteria created during cycling may not have been enough to handle the bioload, and when 1 fish dies, it leads to the ever cascading increase of ammonia and everything dies.

If you could post your stock list (and dates of stocking), and how you stocked your tank, maybe you could get some expert advice on future stocking to prevent livestock loss.

And as Bertoni said, replacing evaporation with saltwater will slowly raise the salinity. I'd also recommend using a refractometer (over a hydrometer) if you aren't already.

I'd also hold off on adding anymore livestock. Keep feeding as normal, and test for ammonia, nitrite and nitrates daily.

 

[ReeferNoob4ever]

It sounds like maybe you added too many things all at once, had an ammonia spike, and now your water change has brought it down. You figure 50% water change means it cut your ammonia in half (roughly). In other words, there was a moment when your ammonia was likely in the .5ppm range which is definitely lethal.