New pinpoint pH meter porblem with MH

[regal]

Reading from pinpoint pH meter with AC adapter goes wild when the MH came on this am. No problem when changed back to battery. Must be interference from the ballasts. MH ballast from championlighting (blueline). Any suggestions.

 

[cali_reef]

Try plugging the PH monitor adaptor in a different outlet.

Certain MH ballasts will cause interference to other electronics, my Icecap MH ballast used to cause all the X-10 stuff go nuts. You can try using a noise filter like this one with the ballast:
http://www.marinedepot.com/md_viewItem.asp?idproduct=YNS3313

 

[alrha]

just use the battery. the adapter is known to affect the readings due to noise. just leave it off and turn it on when you want a reading, the battery will last forever. and if it means spending $2 on a new battery every year, that will be the cheapest thing about your tank.