Beth, I am having a MAJOR problem with hyposalinity

[pontius]

since Friday, I have been trying to lower the SG for hyposalinity. the starting SG was 1.025, and now 3 days later, it is only down to 1.020. I have been steadily adding freshwater. just today, I have replaced 7 gallons of saltwater with freshwater and the SG has not budged at all today. I would guess in all that I have put in 20 gallons of freshwater since Friday. I don't see anyway possible that it's only moved this much. with the lights and equipment, the tank evaporates approx a gallon a day....not nearly enough for the SG not to be moving at all.
I have a refractometer that is perfectly calibrated (tapwater comes out at 0) and is less than a month old. I also have 2 swing arm hydrometers that both concur with the refractometer....1.020.
I don't see anyway possible that a 72 gallon tank with 20 gallons of freshwater could have an SG of 1.020. what is going on??!?!

 

[tjake68]

i started hypo today i went from 20 to15 with 15 gallons of freshwater i have a 65 gallon tank i did3 water changes today and it dropped no problem ive done this before the hard part is getting the salinity back to 20 21 i use a refractor are u sure yours is calibrated right you should have dropped more 10gallons usally drops me 4% i guess every tank is diffrent lol

 

[pontius]

a few more things to add:
the 125 I am currently cycling has an SG of 1.025. I did a taste test, the 125 is a *little* more salty tasting than the 72.
at one point tonight, after adding 3 gallons of freshwater, I tested that tank water to the sump water back to back. the tank water said 1.020, the sump water said 1.010??? so I took a large cup and dumped a couple gallons from the sump into the main tank. an hour later, both the tank and sump read 1.020.
I have been adding a ph buffer the whole time, and the ph is 8.3. but at this rate, it's going to take 50 gallons or more of freshwater, I don't see any way that the ph won't crash.

 

[pontius]

Originally Posted by tjake68
i started hypo today i went from 20 to15 with 15 gallons of freshwater i have a 65 gallon tank i did3 water changes today and it dropped no problem ive done this before the hard part is getting the salinity back to 20 21 i use a refractor are u sure yours is calibrated right you should have dropped more 10gallons usally drops me 4% i guess every tank is diffrent lol
water straight from the tap at room temperature is 1.000, so I'm pretty sure it's right. but even if it were not, it should still be dropping some.
but if you did 15 gallons in a day with no problems and only got a .005 drop, I guess I am safe to do more, that is another thing I was worrying about.

 

[beth]

To do hypo on a 125 is going to take a lot of water change outs. Are you keeping up with pH?

 

[pontius]

the hyposalinity is in the 72. the 125 is the one I'm cycling. I've been putting in a ph buffer and checking the ph

 

[fedukeford]

Originally Posted by Pontius
a few more things to add:
the 125 I am currently cycling has an SG of 1.025. I did a taste test, the 125 is a *little* more salty tasting than the 72.
at one point tonight, after adding 3 gallons of freshwater, I tested that tank water to the sump water back to back. the tank water said 1.020, the sump water said 1.010??? so I took a large cup and dumped a couple gallons from the sump into the main tank. an hour later, both the tank and sump read 1.020.
I have been adding a ph buffer the whole time, and the ph is 8.3. but at this rate, it's going to take 50 gallons or more of freshwater, I don't see any way that the ph won't crash.
O MY GOD, did u seriously taste water out of your tank, with all the fish poo , and bacteria??

 

[pontius]

of course I did. you've never done that?

 

[92protruck]

your sg readings sound about right to me. Adding 1/5th of tank volume ro/di should drop about 5 points. For hypo, most people change out 1/5th every 12 hours to get down to hypo conditions in about 48-36 hours. In your case, thats about 15 gal every 12 hours. If you've only changed 20 gal in 4 days I'd say your readings are about right.

 

[diane4]

I did hypo on a 90 gallon tank and I took a long time to do it. I never dropped more than a point, maybe 2 in 1 day in SG.
I think the slower the better. I think your doing fine going slower and steadier. It gives the fish more time to adjust. It is even more important to take it very slowly when you are on your way back up with salt increases.
Take your time. I wound up stretching my whole hypo ordeal on my 90 gallon tank over 2-3 months. I kept them in hypo for about 6 weeks. I know that is to long, but it cured the ich and the fish all pulled through fine.
My advise from things I learned from Beth, and from my experience with it - take it slow. Good luck to you.

 

[beth]

It is difficult to do hypo in a large display, to say the least, but safer than trying to keep a bunch of fish in an uncycled QT for a month. Of course, there are limits to doing this, like reef tanks, or dsb's.