[tmz]

What do you mean my alk kit will no longer measure my alk properly?


It will measure total alkalinity poperly but the amount of carbonate alakinity in the total alkainity measure will be less.

Alkalinity is not a thing ;it's a measure of many things( bicarbonate,carbonate ,borate,oxide, silcone, magnesium hydroxide,phosaphte ) that nuetralize acid . Calcifying organisms use carbonate alkalinity for calicification forming calcium carbonate into skeletal mass. carbonate alkainity is the portion of total alkainity provided by carbonate/bicarbonate, usually about 96.5% in seawater at 8.0 pH, of the total alk .
A buffer with a higher portion of borate porvides a lower proportion of cabonate/bicarboante and will will provide more borate alk than normal ; the borate portion is unuseable for calcification. Typically, we measure total alk as a surrogate measure for carbonate alkalinity which is of primary interest for the organisms we keep. The borate doesn't count much in this regard.