Meed Help with pH in hyposalinity tank

[Mark NJ]

I am treating approximately 4 fish (approx 12 inches of fish total) with hyposalinity in a 40 gal breeder and a 10 gal sump. It's been a week now and all are doing better but the ph is very unstable. I am doing constant water changes because I had an ammonia spike. The hypo-sal water goes in at 8.3 but a few hours later it's way down to what I am estmating as 7.9 on the color chart. Tank and sump are bare bottom. and I have about 15 lbs of liverock in there that I added from my dark sump (very little life) I siphon all food twice a day. I have 4 filter sponges in the sump to help with bio and salinity is .009-.010. I am adding a buffer called Buffer 8.3 by Kent Marine I think but it won't stay stable. At the same time I don't want to stress the fish with pH swings. What can I do or add to help stabilize pH in this tank. I have 5-6 weeks of treatment left. Any help would be immensely appreciated.
Thanks all, Mark

 

[kevin2000]

Hypo tanks have 2/3'rd less SW than normal tanks so alkalinity (buffer) tends to be low - hence the PH instability. You can add baking soda to bring alk up to normal.

 

[magnetic1]

Would one recommend using the same Kalk dosing water into QT?

 

[kevin2000]

<a href=showthread.php?s=&postid=12052886#post12052886 target=_blank>Originally posted</a> by magnetic1
Would one recommend using the same Kalk dosing water into QT?

No. All you need is to add a bit of baking soda or commercial buffer to fix the problem. Kalkwasser has the risk of adversly impacting PH and you don't give a rip about calcium in a QT.

 

[Mark NJ]

Thanks guys. Baking soda it its