I bet your Mg is low in the salt you are using for your water changes. The best thing to do is setup to do a water change and measure the Mg, Ca and alk of the new freshly mixed water. Most times you will have to adjust the mix to meet what you are trying to maintain in your tank. Once you start doing that you should see less swings in your parameters.
__________________
-Joe
TOTM Sept 2002 | Reefland April 2004 | CORAL Magazine Nov 2007
Featured Tank "Coral Reef Aquarium" 2011 | Reef Spotlight 2018
Current Tank Info: 270G SPS Tank, 140G sumps, 35G Frag Tank, Ultra Reef Akula UKS-200 Skimmer, Apex, Giesemann Spectra 3x250W MH 4x80W T5, 2xReefbrite Tech 72" Blue LED, Triton Dosing, ARID C30 Algae Reactor, Maxspect Gyre
|