Lost 4 fish in 2 days only one still alive, need advice.

[Dkeller_nc]

Just a note, but there's a reason some of us are skeptical of the low alkalinity causing fish deaths. One of the standard methods for preventing/treating ich in a quarantine tank is lowering the specific gravity of the water to 1.010, and in a rapid manner (typically less than a day to go down to that hyposalinity).

Approximately speaking, the alkalinity of seawater that was at 8 dKH at 1.026 would then be about 3 dKH. Moreover, one doesn't typically monitor/dose alkalinity reagents in a quarantine tank, so after 10 days to 2 weeks, the actual alkalinity will be far lower.

 

[RobertT]

Just a note, but there's a reason some of us are skeptical of the low alkalinity causing fish deaths. One of the standard methods for preventing/treating ich in a quarantine tank is lowering the specific gravity of the water to 1.010, and in a rapid manner (typically less than a day to go down to that hyposalinity).

Approximately speaking, the alkalinity of seawater that was at 8 dKH at 1.026 would then be about 3 dKH. Moreover, one doesn't typically monitor/dose alkalinity reagents in a quarantine tank, so after 10 days to 2 weeks, the actual alkalinity will be far lower.

My salinity is a stable 1.025 and tested below 2 dKH sat morning at 1.025. I know KH and PH affect each other I don't think salinity has anything to do with KH. I kind of understand say, assuming each scoop of salt mix contains X amount of alkalinity. Salinity is just a measurement of salt content you can still have a dKH of 8 and 8 PH with salinity at 1.010/brackish. I know this because I have a 29gal brackish tank at 1.010 with a PH above 8 without dosing anything.

 

[Dkeller_nc]

Correct. Up to a point, specific gravity and alkalinity are independent parameters. What I'm getting at is that when treating fish in a QT with hyposalinity, normal ASW is diluted. No attempt is made to increase the alkalinity over what it would be after dilution, which, depending on the original seawater mixes' alkalinity, will be in the 3-ish range initially, and a good deal lower than that after several weeks.

 

[RobertT]

Correct. Up to a point, specific gravity and alkalinity are independent parameters. What I'm getting at is that when treating fish in a QT with hyposalinity, normal ASW is diluted. No attempt is made to increase the alkalinity over what it would be after dilution, which, depending on the original seawater mixes' alkalinity, will be in the 3-ish range initially, and a good deal lower than that after several weeks.

I understand what you were trying to say. But if you have ever kept freshwater tanks and tested the KH you would find that R/O water(at least in my tanks) has a DKH from 4.4 to 6.7 without adding anything. The water that comes out the tap where I live has 10.8 dKH. That stacks with whatever is being added. water source does matters of course.
To the Ick treatment, you described. A few hours a day in a harsh environment vs long term (which my fish endured) may yield much different results. Although now I'm curious as to many fish may have died from said treatment or similar treatments and Ick was falsely blamed as the cause of death.
I've been to several LFS in my area the last few days(I have about a 100 to choose from), they all rule out diseases or parasites and all agree with the exception of one who believes my PH is the cause and KH the indicator. My understanding is a PH from 7.3-8.4 is fine, mine was 7.8ish at the time, but that guy believes anything under 8.0 will kill.

 

[Dkeller_nc]

I'll let others chime in, since you should hear this from more than just one person, but a pH of 7.8 will not kill or adversely affect any saltwater reef fish. Period.

You can look up what I'm describing - it's the "hyposalinity treatment for ich". It typically runs for 4 weeks at a continuously low specific gravity of 1.009 - 1.010. Deaths are rare, and generally are the result of a fish that is already so weakened by ich that it wasn't going to survive anyway. I've not lost any fish doing this, out of at least multiple dozens.

 

[RobertT]

I'll let others chime in, since you should hear this from more than just one person, but a pH of 7.8 will not kill or adversely affect any saltwater reef fish. Period.

You can look up what I'm describing - it's the "hyposalinity treatment for ich". It typically runs for 4 weeks at a continuously low specific gravity of 1.009 - 1.010. Deaths are rare, and generally are the result of a fish that is already so weakened by ich that it wasn't going to survive anyway. I've not lost any fish doing this, out of at least multiple dozens.

I understand what Hyposalinity treatment for ich is and how it works. Water parameters outside of salinity are required to be buffered especially using RO/DI such as PH or you can kill the fish . Also, osmotic shock can kill the fish if salinity is raised too fast. I was just wondering how many do it wrong then blame the parasite.
To my point, if you're doing Hyposalinity treatment right and buffering the water your dKH should never be as low as you described and wouldn't be a fair comparison to what was happening in my tank.

 

[Dkeller_nc]

Take a look at the instructions on the 'net for hyposalinity. Generally speaking, no addition of alkalinity reagents to the base saltwater is advised.

 

[RobertT]

Take a look at the instructions on the 'net for hyposalinity. Generally speaking, no addition of alkalinity reagents to the base saltwater is advised.

I have, you are at minimum required to buffer PH. Raising PH RAISES KH, raising KH RAISES PH. If people are doing it properly, they should be checking and buffering all the water parameters. to be on the safe side.
Tank update: Since I have removed the carbon and Phosguard Sat and began dosing KH to bring it up to normal my dKH has been holding a consistent 8. I have not had to dose for 2 days now. So it would appear at this point my LFS was correct that my media was the cause of my KH being removed at such a rapid pace. And as a side benefit my PH has also raised above 8 and staying a consistent 8.3.