Estimating Dissolved Organic Carbon Levels With Chlorine Demand

Dan_P · 10/07/2017, 12:50 PM

Chlorine demand is the difference between the amount of chlorine added to a sample of water and the measured amount. The magnitude of chlorine demand has been shown to correlate with the amount of dissolved organic carbon (DOC). When the concentration of DOC decreases, chlorine demand becomes smaller. Might chlorine demand be useful in monitoring trends in DOC of aquarium water, or skimmer and GAC reactor performance? Test results to this point are encouraging.

Chlorine demand reduction of aquarium water, presumably because of DOC reduction, have been observed for both GAC reactor and skimmer effluents. A change in magnitude of chlorine demand reduction might be useful in deciding when to replace the GAC or to clean the skimmer. A forty day study of the effluent of a GAC reactor indicates no change in chlorine demand reduction so far.

Trends in DOC levels in aquarium water have not been seen because of the small number of observations. Weekly observations will continue for a few months longer. Daily and hourly observations are also planned. Because ammonia also reacts with chlorine, the amount of chlorine demand attributed to ammonia in these measurements needs to be understood. Ways to simplify the analysis are being explored and will be posted.

10/07/2017, 12:50 PM	#1
Dan_P Registered Member Join Date: Aug 2014 Posts: 1,432	Estimating Dissolved Organic Carbon Levels With Chlorine Demand Chlorine demand is the difference between the amount of chlorine added to a sample of water and the measured amount. The magnitude of chlorine demand has been shown to correlate with the amount of dissolved organic carbon (DOC). When the concentration of DOC decreases, chlorine demand becomes smaller. Might chlorine demand be useful in monitoring trends in DOC of aquarium water, or skimmer and GAC reactor performance? Test results to this point are encouraging. Chlorine demand reduction of aquarium water, presumably because of DOC reduction, have been observed for both GAC reactor and skimmer effluents. A change in magnitude of chlorine demand reduction might be useful in deciding when to replace the GAC or to clean the skimmer. A forty day study of the effluent of a GAC reactor indicates no change in chlorine demand reduction so far. Trends in DOC levels in aquarium water have not been seen because of the small number of observations. Weekly observations will continue for a few months longer. Daily and hourly observations are also planned. Because ammonia also reacts with chlorine, the amount of chlorine demand attributed to ammonia in these measurements needs to be understood. Ways to simplify the analysis are being explored and will be posted.