Preparing IO salt

[stancfii]

When freshly mixed at 35ppt, the dKh is about 11. If I make 5 gallons at 35ppt, what can I add, and how much of it, to drop the dKh to 8-8.5? I assume vinegar would work, but not sure how much to use. I'd like to avoid an alkalinity spike with my water change.

Thanks!

[Wills612]

How long are you waiting to test? What % are your changing? The increase in ALK might be negligible. I change about 10% a week with IO and don't really notice a increase in ALK testing a few hour after a water change. I try to stay stable around 8.5-9.

[bertoni]

Vinegar won't help. It's an organic acid, so when it is consumed by bacteria any alkalinity that it bound up is released. You will need to dose with a mineral acid, such as hydrochloric or sulfuric acid. I tend to avoid working with toxic chemicals, but I probably can find a dosing rate if you're interested.

I agree that the difference in alkalinity from a water change might be very small.

[stancfii]

I suppose you guys are right. It works out to be about a 12.5% water change every two weeks. At that rate, it might bump my dKh by .5, which is harmless enough at this point. I have ~40gal total water volume.