Conductivity readings affected by fluorescent lights

badonkadonk · 07/29/2008, 12:12 PM

My AC3P conductivity readings drop by about 10 ms/cm whenever my T5 fluorescents (2 x 48") for the refugium, located about 6 feet from the AC3P, are on. The conductivity probe is in a drip cup over the sump about midway between the refugium and the AC3P. I tried plugging the AC3P transformer into a separate circuit, but that didn't seem to make a difference. I assume it is the physical proximity of the probe/leads/AC3P to the fluorescent lights. Anybody else see this? Solutions? (the readings drop by between 5 and 15 ms/cm, so it is not a simple matter of subtraction - though the readings when the lights are off are stable at 52-53). TIA

clp · 07/30/2008, 09:43 AM

Make sure that the ballast as well as the ballast hood is electrically grounded. I also recommend installing the cond. probe in a drip cup if you haven't already done that.

Curt

07/29/2008, 12:12 PM	#1
badonkadonk Registered Member Join Date: May 2005 Location: Malibu, CA Posts: 227	Conductivity readings affected by fluorescent lights My AC3P conductivity readings drop by about 10 ms/cm whenever my T5 fluorescents (2 x 48") for the refugium, located about 6 feet from the AC3P, are on. The conductivity probe is in a drip cup over the sump about midway between the refugium and the AC3P. I tried plugging the AC3P transformer into a separate circuit, but that didn't seem to make a difference. I assume it is the physical proximity of the probe/leads/AC3P to the fluorescent lights. Anybody else see this? Solutions? (the readings drop by between 5 and 15 ms/cm, so it is not a simple matter of subtraction - though the readings when the lights are off are stable at 52-53). TIA

07/30/2008, 09:43 AM	#2
clp RC Sponsor Join Date: Aug 2001 Location: San Jose, CA Posts: 4,311	Make sure that the ballast as well as the ballast hood is electrically grounded. I also recommend installing the cond. probe in a drip cup if you haven't already done that. Curt