water change question

[Animal-Chin]

My sps don't like big changes and here is why...

I carbon dose with biopellets and a reactor. Because of this I keep my alk at 7 as any higher and my acro's burn their tips. So I have a dosing schedule that keeps my alk steady at 7 all the time.

My salt mixes WAY higher than that. I've measured my instant ocean alk at 13 before but its always higher. If I do a larger water change (say 20%) my alk will swing that day to 8 or 9 and the next day my acro tips will burn. It will drop over the next few days though.

Considering I run a phosphate and nitrate reactor my main reason for water changing now is to add trace elements back into the water. For me doing smaller weekly changes accomplish this and don't create the alk swings I'm trying to avoid.