I would suggest also that your cal is a bit on the hi side relative to your alk levels. Let it come down a bit and you will find it easyer to maintain the alk level. At 490 cal your Dkh when balanced to NSW ratios would be 18DKH!! also remember the cal to alk ratio is about 20:1 so a 1 meq alk change will only shop up as a 20ppm cal change.
__________________
|