Ph value goes up..

[onad75]

I have a Ac Jr and i am wondering why my Ph value go up everytime i hook up my serial port to my comp. My normal Ph value is around 8.0 but as soon as i plug the serial port the value goes up to 10.0 or higher.
Why is it happening?

Thanks

[bill-e]

Ground loop. You need the serial ground isolator.

[theop]

Could you post a link to what this is exactly or where to get one?

Is it just this? http://www.marinedepot.com/ps_ViewItem~idProduct~NS7115.html

[bill-e]

That's it.

[onad75]

Thanks for the reply, but man $45 to fix that? why they design this controller like that.

[NeveSSL]

Probably to keep the initial cost down. :)

Brandon