What doesn't?
Adding calcium chloride doesn't lower alkalinity?
Most of the time people only change a small percentage of the total amount of water of their tank. If people only change about 5-10% of the total column, then even if the ALK is at 10-13, it doesn't make that much of a different at all. I am curious as why it is so important to add acid into it to lower the ALK to 8 or 9?
Of course, if you are going to change like 50% or so, then it will be a big deal.
No, not in any measurable degree, as long as the dose is reasonable. If you dose enough to cause a precipitation event (a snowstorm), that's be a bit different. That takes a large overdose, though.Adding calcium chloride doesn't lower alkalinity?
Also knowing.my tank has been a steady 10.5 alk, should I leave 11 alk of of instant ocean, and just raise the calcium?
What calcium are you getting with the IO? May not need to raise it.