Marine and Freshwater Carbon Study
Fresh and Saltwater Nitrifying Bacteria Experiment
pH Change in Sample Containers
Tapwater, RO and Saltwater pH Change Study
Tapwater, RO pH Change while Aerating Storage Containers
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Carbon, pH and Other Marine Research

Tapwater, RO and Saltwater pH Change Study

Disclaimer

While the following experiments were completed with the greatest amount of care and precision, they were nonetheless performed in our home with test kits and materials on hand. As such, results should not be considered scientifically conclusive.

pH Change Study

Goals:

To study pH change over 36 hour periods of local tapwater, tapwater treated with Prime, water made with a Hydrotech reverse osmosis unit, and saltwater made from RO water in the following environments:

• uncovered, non-aerated container
• covered, non-aerated container
• uncovered container aerated with an AquaClear Mini powerfilter without media
• covered container aerated with an AquaClear 1000 powerhead

Equipment:

Hardware

• four 3000 ml plastic containers with lids
• one AquaClear Mini hang-on filter without media set for low aeration
• one AquaClear 1000 powerhead

Test Kits

• Hanna Instruments HI 931700 pH Probe and Monitor
• Aquarium Pharmaceuticals Freshwater/Marine Nitrate NO3 Test Kit
• set up identical plastic containers at room temperature with 2500 ml of water from one of four water sources
• measure pH for one minute in each container at times specified in the data table below. pH probe will be rinsed for 5 seconds in a separate container of RO water after each container's pH has been measured and before the next container's pH is measured
• pH probe will be stored in a separate container of RO water between measurements
• lids on covered containers will be loose for easy removal

Water

• SERIES A:
  RO water samples will originate from the same tap at the same time
• SERIES B:
  saltwater with a specific gravity of 1.026 made from RO water
• SERIES C:
  untreated tapwater samples will originate from the same tap at the same time
• SERIES D:
  Prime-treated tapwater samples will originate from the same water storage container at the same time

SERIES A Data:

Date and Time

pH

pH

pH

pH

SERIES A Observations:

• Overall, in the aerated RO samples, there was a steady increase in pH.
• In the non-aerated RO samples, there was a slight increase in pH during the first day, with a large increase overnight, then a slow drop in pH during the second day.
• In both covered and uncovered, aerated and non-aerated samples there was in increase in pH five hours after aeration ceased.

SERIES A Conclusions:

Aerated RO water samples, both covered and uncovered, gave the highest and slightly more predicable increase in pH.

 

SERIES B Data:

Date and Time

pH

pH

pH

pH

SERIES B Observations:

• Non-aerated, covered and uncovered saltwater pH changed the least over the two day test period.
• In aerated saltwater covered and uncovered samples, pH rose steadily. 
• Five hours after aeration ceased, pH dropped slightly in both covered and uncovered samples.

SERIES B Conclusions:

Saltwater needs aeration in both covered and uncovered situations to allow pH to increase to its fullest advantage.

SERIES C Data:

Date and Time

pH

pH

pH

pH

SERIES C Observations:

• Non-aerated, covered and uncovered untreated tapwater pH changed the least over the two day test period. 
• Compared to RO water pH changes, untreated tapwater pH increase was higher.
• In aerated untreated tapwater covered and uncovered samples, pH rose somewhat erratically. 
• Five hours after aeration ceased, pH continued to rise slightly in both covered and uncovered samples, while slightly dropping in covered and uncovered non-aerated samples.

SERIES C Conclusions:

Untreated tapwater needs aeration in both covered and uncovered situations to allow pH to increase to its fullest advantage.

 

SERIES  D Data:

Date and Time

pH

pH

pH

pH

SERIES D Observations:

• Non-aerated, covered and uncovered Prime-treated tapwater pH changed the least over the two day test period. 
• Compared to RO water pH changes, Prime-treated tapwater pH increase was higher.
• In aerated Prime-treated tapwater covered and uncovered samples, pH rose relatively steadily. 
• Five hours after aeration ceased, pH continued to rise slightly in all aerated and non-aerated, covered and uncovered samples.

SERIES D Conclusions:

Prime-treated tapwater needs aeration in both covered and uncovered situations to allow pH to increase to its fullest advantage.