Testing Tips

General Data/Test Kit Info
Temperature
ph/TDS
Dissolved Oxygen
Nitrate-Nitrogen
Phosphorus
Turbidity
Alkalinity
Iron
Kick-netting
Leaf Packs and Hester-Dandy Plates

 

 
General Data/Test Kit Info
To help keep your kits organized, a list of what should be found in each test kit can be found on each of the "Test Instructions" sheets in the Creek Connections Handbook for Water Quality Analysis.
Extensive efforts to update the Creek Connection's Handbook for Water Quality 
Analysis now provide classes with better and more complete water test kit instructions.  Please use them.  If you read carefully and follow the directions in the handbook for each water test, your results will have better accuracy. Don't use the HACH  Company instructions en- closed in each kit - they are not as thorough and clear.
Collecting Tips:
  • When collecting sample from stream, be sure to extend pole the enitre way (if using cup and pole to collect sample). Make sure your sample A and sample B are from the same location in the creek. You use them to designate two trials of chemical work that allow you to check the accuracy of your reults.
  • Make sure you rinse your collection device with creek water before collecting samples.
  • Limit the splashing caused by the bailer as this may add more dissolved oxygen into your sample.
  • Beware of the fast water. When collecting a sample have 2 or 3 people on the bailer.
  • Be conscientious of the water temperature. Do not enter the water when it becomes too cold.

One of the most important steps of any chemical tests should be done before sample water is measured or chemical packets opened. Always rinse glassware with distilled water before beginning a chemical test.
If chemicals or sample water are left in the containers, they may alter your results the next time you use the test kit. Each and every time you use a test, it is important that you clean all of the chemicals and sample water from inside the testing containers. For a real tough job, you can even use coarse-bristled brushes to scrape the bottom and sides of the containers. (Ask a Creek Connections intern or coordinator if you would like to obtain one of these.) Always rinse out with distilled water when you are done!

When collecting data, we ask schools to do at least two trials on their water samples (conveniently labeled as Sample A and B). This is to double check the accuracy of your results. Both trials should yield very similar results since it is the same creek water taken at approximately the same time. If the results between the two vary significantly, please do a third trial. Also, make sure you indicate differing trial results when submitting your data on-line, especially if you did not do a third trial.
When pouring water from bottles into tubes, if you pour too much in, do NOT pour the overflow back into the bottle. This can cause contamination of your sample. Instead, pour it onto the ground or into a sink.

Be careful not to confuse a test tube (which have a cap) for a measuring tube.  They are very different volumes!!!  Also, there is a thin plastic cylinder/tube found in some of the phosphate kits that holds the eyedropper.  Some schools have mistakenly used this as the measuring tube.

Many of our testing parameters require the addition of chemicals for various reasons. These chemicals are found in "Powder Pillow Packets" that all Creek Connections participants should be familiar with by now. It is essential that these chemicals be administered correctly to obtain the most accurate results. To ensure correct results, remember to be careful when opening the packets by abiding by the following rules:

1. Always use scissors or nail clippers to open the chemical powder pillow packets. One of these two objects will always be found within the test kit. Avoid using your teeth to open the packets at all costs! Although none of the chemicals are gravely dangerous, some of them can be harmful if ingested.

2. Be conscious not to shove your fingers or nails into the packet to pry it open. The residue found on your hands can alter the chemicals and have an unwanted effect on your results. Also, if you accidentally put your chemical-laden fingers or nails in your mouth, you risk ingesting the harmful chemicals. To avoid both of these problems, after cutting open the powder pillow with nail clippers or scissors, simply hold the pillow packet between your index finger and thumb of both hands, one on each side near the opening on top, and push the ends together. This will easily force the pillow packet to open without altering the chemicals within and without getting the chemicals on your fingers. Always wash your hands after chemical testing!



3. After using the chemicals for testing purposes, make sure the garbage is disposed of properly. Be careful to place the empty pillow packets into a waste bin if you are in the classroom or into a trash bag if you are out in the field. Do NOT simply throw the garbage on the ground after the test has been completed.
Deionized (demineralized) water is included in the Hach Phosphorus test kit. The instructions for the high range Nitrates test indicates that the deionized water is required. We contacted Hach in November, 2004 to determine if the deionized water is required for the test and why. A Hach representative assured us that distilled water is allowed to be used in the tests. The only caution given was that we be sure that the chemical we are testing for is not found in the distilled water we are using. So, if you are unsure, you can test your distilled water (using the low range tests) to determine if it contains any nitrates or phosphorus.
To properly dispose of the liquids after testing, you need to use the designated waste container (this container should be clearly labeled "Waste"). When you are done running a test, pour the chemical and water solution into the waste bottle. Then when you get back to your school, you or your teacher can flush it down the drain with lots of water. Only in the special case of the Nitrates test do you need to give waste back to Allegheny College. During the Nitrates test, it is possible, when you add NitraVer 6 Nitrate Powder Pillow to the water sample, for cadmium particles to be produced. The solution with the cadmium particles should be placed in a specially marked container for cadmium waste. It is a metal that should not be dumped down the sink. Your teacher can give this waste container to Allegheny College at the end of the year for proper disposal. All the chemical packets and other material garbage should be placed into a sealed bag labeled "trash", which can then be emptied into a garbage can back at your school.

A few words of caution when entering data online:

1.  Be careful entering the numbers.  If you mistype your results off your data sheet, we will never know you made a mistake. 

2.  If your sample A result was significantly different than your sample B result, and you averaged them anyway without doing a third trial - PLEASE tell us.   Indicate the disparity between samples in the "extra notes" section of the submission form.    This way we can "flag" this piece of data as being a little "fishy". 
Please be very specific about sample location on your data page!  We need to have a clear idea about where you are actually testing.
Temperature

HOLD, do not set, the thermometer in the sample bottle (not stream) for at least one minute.
pH/TDS Meters
Remember to calibrate the TDS meter to 210ppm.
Please be very careful with your pH and especially you TDS meters.  They are delicate instruments and should be handled gently and according to the instructions that they came with.  Under no circumstances should they by dropped.  Also, you should only turn them on after submerging them in water, and turn them back off again before removing them.  The glass bulb should not be exposed to air while the meter is on! 
Remember that the thermometer glass and the little glass electrode at the bottom of the meters are very delicate.  Do not force them to the bottom of the sample or play with them because they will break!
When the pH/TDS meter batteries are low, it may still turn on, but will display obviously incorrect numbers (example:  pH of 125), will not stabilize on or near any reasonable value, or will not calibrate.  If you notice any of the "symptoms" described above, replace the batteries.  They are standard Zinc Air type 675 hearing aid batteries and can be purchased in packages of four from Wal-Mart, K-Mart, Radio Shack, and most drug stores. At Allegheny, we buy the Radio Shack variety  (only because its closest): Radio Shack Hearing Aid Enercell E675 HPX. 
*If you are sampling and do not have an extra set of batteries, the life of the used batteries can be extended slightly by rubbing both sides of each battery with a pencil eraser.  However, this is only a very temporary solution and does not work with totally dead batteries. 
To calibrate the TDS meter, turn the smallest flathead screw next to the clip on the back of the meter.  Do not unscrew the back cover of the meter.
Be gentle on the TDS meters when calibrating.  The plastic screw is easily stripped.  If the meter does not calibrate, try to change the batteries using the directions in the Handbook.

Dipping the meters too deep in samples is the most common way of getting moisture inside them.  To prevent this from happening, only the part of the meter that is covered by the cap should be submersed (depth of approximately 1.5 inches).


If moisture does find its way into the meter, it may condense inside and temporarily short-out the electronics.  If this happens, remove the battery cover or top, depending on what type of meter you have, dry off the batteries and whatever else you can with a paper towel, and let the unit air out until it works again.  Often, the batteries go dead if moisture is allowed to remain inside the meter for a extended period of time. 
Always rinse both meters with distilled water between calibrating and testing.  If you do not, you may contaminate the samples with small amounts of calibration solution.  Also rinse the meters with distilled water before putting  the cap back on for storage.  This will prevent dissolved solids present in tap or creek water from building up on the bulb (pH meter) or the electrodes (TDS meter) when the water evaporates during storage.
Using the meters, if you are getting an unrealistic reading or no readings at all, make sure the cap is off the bottom!
Dissolved Oxygen
In the dissolved oxygen test, first add powder pillows 1 & 2, shake, and allow to settle.  Then add the third powder pillow and shake again to eliminate the particulates before titration.

a) When using the eye dropper for the dissolved oxygen test, hold it VERTICAL (straight up and down) when adding drops to the square mixing bottle (during the titration process).  The drop sizes (volume) are different and inaccurate if the dropper is held at an angle.  All schools need to have consistent, vertical drops so that data can be compared.

b)  Make sure you swirl the square mixing bottle after each drop.

c)  Place the square mixing bottle on a white piece of paper or other white background to better see color changes.

d)  Remember, you can always add an additional drop.

When sampling on a cold day, it is still important to do the Dissolved Oxygen Test and read the temperature as soon as you collect the water.  For DO, at least put in the first two chemicals (found in the ziploc bags) to trap all the available oxygen, then you can take it back to warmth to finish the test.  Make sure you don't get any bottled air bubbles.
Determine if your solution has turned clear during the titration process by placing the square mixing bottle on a white sheet of paper or against the white cap of the dissolved oxygen 3 chemical container. Disregard counting any drops that did not make the solution clearer.
Make sure to rinse equipment out well with distilled water after doing testing to assure that future results will not be affected by contamination. 
Nitrate-Nitrogen

 

When filling up the test tubes for the Nitrates test, add water to the lowest mark on the test tube.  Not the top line!!
For the Nitrates test, when comparing the two test tubes with the color comparator wheel, make sure that both caps are on the 2 tubes to avoid spillage.  Plus, don't have one cap on, one cap off - that inconsistency will create an unequal shade for the water.
If your nitrate water turns orange instead of pink it's not your fault.  According to the HACH Company lab technicians, the reason the water turns orange instead of pink is because moisture (humidity) is getting into the little foil packets of NitraVer 6 and NitraVer 3, corroding these chemicals.    Either the foil or its seal is faulty.   It was a manufacturing problem, not CC student error in technique.   It is happening all over the country.  HACH will replace the ziploc bag of chemicals if this is continuously occurring with your nitrate test.  Let Creek Connections know so we can get replacements.
Make sure to rinse equipment out well with distilled water after doing testing to assure that future results will not be affected by contamination. 
Phosphorus

When testing for phosphates, use a stopper (not your thumb!) to mix the contents within the square bottle

 

Make sure to rinse equipment out well with distilled water after doing testing to assure that future results will not be affected by contamination. 
Turbidity
Turbidity Kit - When adding the Standard Turbidity Reagent (step 4), don't forget to shake it first.  **You must add the turbidity reagent to the distilled water tube (not creek water) in increments of 0.5 mL.  Make sure that you fill the eye dropper up to the 0.5 line.  DO NOT ADD just one drop or fill up the dropper all the way!
Make sure to rinse equipment out well with distilled water after doing testing to assure that future results will not be affected by contamination. 
Is your turbidity test out of range? Even after reducing the volume of water to the 25 mL line or even to the 12.5 mL line, is the water still too cloudy to see the dot?
If so, the LaMotte Company suggests a dilution: dilute the turbid water with distilled water (keeping track of the volumes of turbid and distilled water used) until the water is clear enough that you can see the black dot. Determine the turbidity of the diluted sample, then calculate the turbidity of the real sample by multiplying by the dilution factor.
Also, when collecting test kit waste, e.g., cadmium waste from the nitrates test, or barium waste from the sulfate test, be sure to store the waste in a container with a screw top, not a pop top.
Alkalinity

a)  When using the eye dropper for the alkalinity test, hold it vertical (straight up and down) when adding drops to the square mixing bottle (during the titration process).  The drop sizes (volume) are different and inaccurate if the dropper is held at an angle.  All schools need to have consistent, vertical drops so that data can be compared.

b)  Make sure you swirl the square mixing bottle after each drop.

c)  Place the square mixing bottle on a white piece of paper or other white background to better see color changes.

d)  Remember, you can always add an additional drop
Make sure to rinse equipment out well with distilled water after doing testing to assure that future results will not be affected by contamination. 
Iron
To avoid getting inaccurate Fe test kit results caused by the reaction of the liquid in the FerroZine Iron Reagent Solution Pillows with the metal in the scissors or clippers you are using to open the pillow, be sure to:
1. Avoid using rusty scissors or clippers to cut open the solution pillow;

2. Wipe off the scissors or clippers before cutting open the solution pillow;

3. Hold the solution pillow straight up and down so that all the liquid is in the bottom of the pillow;

4. Wipe off any purple color that develops in the cut area of the solution pillow before adding the contents to the water sample.
Kick Netting

How to Kick Net
   It's important to take note that there is actually a system for kicknetting.  You cannot simply place the net in the stream and hope to catch something.  Here are a couple of reminders to help make sure your kicknetting is successful.  First, you need at least one partner. Find a riffle (small rapids in stream) and approach a spot in the riffle from downstream. A riffle is where a larger variety of insects will be found; they like the fast moving, well oxygenated water.  One person should hold onto the two handles and place the unfolded kick net snugly into the substrate (rocks, gravel, and mud on stream bottom).  The partner (the kicker) should anchor the net down with large rocks found near the net.  Pick up any other large rocks and brush off any attached insects in the directions of the net.   Then the partner must kick up the substrate a square meter in front of the net.  Any insects hiding in the rocks and mud will be knocked loose into the water column and get caught in the net. 
   To remove the net and invertebrates from the stream,  clean off the rocks you used as an anchor, and carefully lift  the net out of the water. Have the kicker grab it from the bottom of the net.  Don't let anything fall off the net and carry it to shore.  You can place the nets on the ground on a white table cloth or sheet to keep the insects from escaping through the back.  The insects and other animals can be removed from the net with forceps.

Sight Search

 
 
Leaf Packs and Hester-Dandy Plates
To sample macroinvertebrates that live within the substrate, leaf packs and/or Hester-Dendy plates may be used. Leaf packs are created by taking a mesh onion or orange bag and filling it with leaves. The bag is then sealed with a string and marked with a bright ribbon or flagging tape. Hester-Dendy plates are created by taking 5-2 inch square pieces of masonite, fasten them together with a hook screw, and place washers between each layer. A string is then tied to the hook and a ribbon is added for identification purposes. Another way to acquire either pack is to place an order for them pre-assembled at an ecological sampler provider like Wildco.
To use the packs: select a place in the stream like a riffle or a pool and place the pack in the water. Take the string and secure the pack to a nearby rock or log. Within two weeks to a month, macroinvertebrates should begin using the pack for a habitat. When the packs are retrieved they can be examined for what kinds and how many macroinvertebrates used them for a home.


Water Chemistry Information Page