Here we go again...

[labrown]

We did another water change, about 30 gallons in a 55 gallon tank, and when we put the last 10 gallons in, the two firefish died, and now my yellow tang is acting weird, not swimming much, struggling to breathe it seems. But I can't imagine there isn't enough O2 in the water because the water was agitated a lot when we added the new water. My levels are all fine, ammonia and nitrite at 0, nitrate at a very reasonable level, and pH, spec gravity and temp are all fine. I can't figure out what is going on. Last water change we lost our two cleaner shrimp. I am totally at a loss, any suggestions would be greatly appreciated!!!

Specs, 55 gal FOWLR, about 35 lbs liverock ( l know we need more) Two false perc clowns, small yellow tang, many snails and a pencil urchin.

[Bill S]

What is a "reasonable" level?

What are you measuring your salinity with?

Where are you getting your water from?

What salt are you using?

I can tell you, I can do a 5 gallon change on our nano, which really holds about 9 gallons. NOTHING is affected by it...

[labrown]

What is a "reasonable" level?
ph, 8.2
Ammonia, 0
Nitrite, 0
Nitrate, less than 20

What are you measuring your salinity with?
Two separate hydrometers, and I've had them checked to make sure they are accurate

Where are you getting your water from?
The tap, then adding essential elements

What salt are you using?
Instant Ocean

[labrown]

Both my yellow tang and my hawkfish seem to be breathing heavily too.

[Bill S]

Well, you kind of have me stumped. So, here we go:

Your hydrometers - are they the "swinging arm" type, or the floating kind with a long thin top of glass. If they are swinging arms, please throw them away.

Tap water: Please. Just use RO/DI water. Yeah, I've used tap water for years - about 30 years. 5 years now with RO/DI and MUCH better results. Sometimes tap water is just fine, sometimes it isn't. With BIG water changes, it just isn't worth the risk. Sometimes chlorine dissapates, sometimes it doesn't. RO/DI water is cheap. Fish/inverts aren't.

[labrown]

I have heard of RO/DI water but don't really know what it is...

Oh, and both of my hydrometers are of the swinging arm type, but I've never seen a different type.

[C.Mydas]

My first thought was chlorine. You can smell the chlorine in our tap water (Pflugerville). Chlorine takes 24 hours to dissapate out of water. Switch to RO/DI, like Bill recommended.

[opium89]

Tap? Egads man. My tap water isn't even suitable for drinking. I hope you're at least using a dechlorinator. You've more than likely poisoned them.

[labrown]

Tap? Egads man. My tap water isn't even suitable for drinking. I hope you're at least using a dechlorinator. You've more than likely poisoned them.

For at least 4 months I used the exact same tap water and never had any problems with it. I've had the same fish for about 6 months now and only within the last month have I been having problems with it.

[labrown]

Chlorine takes 24 hours to dissapate out of water.

Very interesting fact. I am sure I will switch, once I figure out what RO/DI is...