Fish dying!!!!

normally i would agree that turning a uv off would not cause this large of a problem, normally the tanks bacteria would compensate. but the tank is only 4 months old the bacteria is not established. and any changes cause larger reactions.

 

This is true, but it isn't going to kill the fish. My system ran successfully at 7.8 for awhile and there are other members on here that run about that same as well.

 

I understand what you are saying about only being 4 months old, but then I guess what you are saying also would have to do with how much LR is actually in the tank. Also, what kind of bacteria are you talking about killing as well? With the params all being good, the tank has been cycled and there should be a good deal of beneficial bacteria to take care of the bioload which would have nothing to do with the sterilizer of course.

 

its not the bacteria i say could be killing the fish. its lower oxygen levels from turning the uv off, thats allowing more bacteria to colonize in the water itself.
which would eat oxygen.

i learned the hard way about what a bacteria imbalance can do in our tanks.

 

I get my water from RO/DI unit I have and I keep my salinity at 1.024. I did start dosing with Kent Marine Purple Tech about a week before they started dying. I also purchased a PH buffer to bring the water to 8.4. The UV has been turned back on and I pointed the powerheads towards the surface for more oxygen exchange. All I have left are a wrasse and a dartfish. I guess I should wait a couple of weeks to see if they survive to buy any more fish.

 

surface agitation is really important its what helps oxygenate the water. without it gases are trapped in the water. maybe that was your problem?

i have never used kents purple tech, so i haven't a clue whats in it. but unless you over dosed it i don't see it being the problem.
your ph is low but as stated above others run their tanks at that ph without a problem. my tank suffered from low ph i went threw so much buffer till i than went to kalk. it worked but is something you really need to read up on before starting to use it. not sure if you have ever used it or read up on it? if not used properly it can cause problems.
recently i tried a product called blue life clear fx pro, it says on the container it stabilizes ph. i thought... ya right. i bought it for the carbon and gfo. well i put it into my reactor and in a week i thought why is my ph so high. i started to adjust my kalk. till finally i realized i no longer needed the kalk the clear fx pro had resolved my high alk and low ph that i could never get right no matter what i tried.
the clear fx pro did not work as well in just a high flow area i didn't see these results till it went into a reactor. oh its in the bag still but in a reactor. i read you have a canister filter? it might work just as well in there? that i can't be sure of since i have a sump. but from what i under stand canister filters force water thew them. it might be worth a try.
i have had to the clear fx pro on line. but recently my local store got it in for me.

the stuff says it will last 3 to 4 months, but for me it lasted 2 months, when i seen my ph starting to drop again i changed the bag and the ph went back into range... night 8.0 day up to 8.3

 

The Kent recall was for carbon, not salt.
Not knowing what's in Kent Purple Tech, I would stop dosing it, especially if you don't test for the things that are in it. Maybe an iodine overdose, if that's an ingredient in that product.
Also, you didn't list your ammonia reading.

 

I'm using Instant Ocean salt and keeping it at 1.024 and have an instant ocean hydrometer. I turned the uv light back on. I use RO/DI water. My powerheads were not pointed towards the surface before, now they are. I also started using a PH buffer to bring the PH to 8.2. Have not tested for copper but have not lost one of my inverts. Right now, all that is left is one wrasse and a dartfish. Maybe turning the uv back on, pointing the powerheads towards the surface for more oxygen and raising the PH will help. We will see. Thanks for all the advice

 

I haven't tested for ammonia cause I can't find the test kit but I figured my ammonia would be zero if my nitrates and nitrites were also zero.

 

If you have prime or amquil plus or something similar that may help save the fish that are still alive.its not a fix for the problem but it may help.it has saved my butt afew times and many others aswell