- Retrieve an empty nutrient rack from the lab fridge if needed and record the color key on the sample log sheet.
- Tubes are inverted when empty and should not be turned over until filled
- Never touch the inside of the cap or tube since residue from your fingers can contaminate the sample – soap contain phosphates. If unavoidable – rinse several times.
- Nutrients are normally drawn from the middle valve – fill the tube with ~25mls, cap loosely, shake then dump. Repeat three times.
- Double check the tube number matches the rosette bottle number.
- Fill the tube completely then flick out several mls so the sample reaches the base of the neck/threads. Cap tightly.
- Draw one sample per rosette bottle (except on the surface bottle). If tube 24 is not needed, draw a duplicate surface sample.
- Once all the nutrient samples are drawn:
- Carefully tip the nutrient rack until you can see the sample through the cap of each tube – if a tube is empty and not inverted, double-check the sample log and fill if necessary.
- fill out a sample label (from the sample log clipboard) with the time, your initials, total number of samples
- Wrap the label around tube #1 and carefully re-insert into rack – be sure to include the extra surface sample to the sample count by listing it as “+1”
- return the filled rack to the nutrient fridge right away.
- add your initials to the bottom of the sample log’s nutrient column
Common mistakes are empty tubes that shouldn’t be; missing duplicate surface sample; contaminated samples; and duplicate draws – two sample tubes filled from the same bottle
| < Prev | Next > |
|---|
