8  Maintenance Notes

8.1 Water Quality

8.1.1 Sonde and Sensor Updates

Chlorophyll units were changed from µg/L to RFU beginning on 01/01/2025 and continuing through presently collected data. Chlorophyll data collected prior to 01/01/2025 are still reported in µg/L. The CDMO is currently working on changing past data to RFU. If downloading chlorophyll data from the CDMO please pay close attention to reported units.

8.1.2 Sonde and Sensor Failures/Malfunctions

There was a sonde (Sparrow, SN:24G103007) failure on 05/28/2026 13:15 at Pellicer Creek. Unable to connect to or turn on the sonde. Sensors were removed and post deployment procedures were performed on another data sonde. All sensors were in good working condition except for Chlorophyll/Total Algae Sensor (SN: 24H100409). Missing raw/bin deployment file for the gtmpcwq052826 deployment. Sonde was sent to YSI for repairs. YSI determined that the power/comm board stopped functioning, the depth sensor was not reading correctly, and the depth connector on the main board was malfunctioning. The sonde was repaired under warranty.

8.1.2.1 Datetimestamp Recording Issues

There were data sonde (Dorian, SN: 20C201711) datetimestamp recording errors throughout most of the 04/15/2026 deployment at San Sebastian. Seconds were not recorded at 00 but ranged from 01 - 40 seconds. Sonde may be experiencing issues with internal clock. #### Wiper Brush Issues

The wiper brush fell off on the following deployments:

Pellicer Creek:

  • March 4 - March 7, 2026 (Davy Jones, SN: 24G103008) central wiper SN: 23G1004212

8.1.2.2 Depth Issues

Ram rod broke inside sonde tube during the sonde exchange on 10/07/2025 10:15 at Fort Matanzas. The metal end of the ram rod could not be immediately retrieved and was stuck inside resting on the pin at the bottom of the sonde tube. The sonde is positioned approximately 3 inches higher than normal for data collected between 01/01/2026 00:00 through 05/01/2026 12:00. Depth data does not appear to be influenced by the small change in depth. Piece was finally retrieved for data beginning on 05/01/2026 12:15.

8.1.2.3 Broken Data Files

The following is a list of deployments that experienced broken data files and all had a sensor malfunctions:

  • Pellicer Creek: Davy Jones (SN: 24H100562) - Wiped CT sensor malfunction. Sensor connecting and disconnecting during post cal. Data file split into three files after retrieval on 04/29/2026 between 13:30 and 14:00 timestamps for 04/15/2026 10:45 deployment;

  • Fort Matanzas: Egret (SN: 24G104084) - Missing pH sensor readings; invalid sensor location (Port 1) at post check. Data file split after retrieval on 06/17/2026 between 12:45 and 13:00;

  • Pellicer Creek: Davy Jones (SN: 24H100562) - Possible central wiper malfunction, data file split on 07/12/2026 13:45, missing wiper voltage values throughout deployment

8.1.2.4 Chlorophyll Sensor Issues

  • San Sebastian: Megalops (SN: 16J102351) - Chlorophyll probe broke off inside bulkhead of data sonde. Sensor removed and trashed. Megalops removed from rotation and replaced with Nautilus.

8.1.2.5 Turbidity Issues

  • Fort Matanzas: Barbossa (SN: 16D102988) - Turbidity sensor causing red light and shutdown of data sonde when connected during post deployment checks on 05/14/2026 08:00.

8.1.2.6 Telemetry

Research staff installed new telemetry equipment including a Storm 3 data logger, data output adapter, wiring, and battery on March 4, 2026. Missing all water quality data on March 4, 2026, 13:15; attributed to attaching EXO cable to data sonde and completing the new telemetry install. The station is now actively transmitting data.

A new EXO template was installed on 04/15/2026 10:45 to change chlorophyll units from µg/L to RFU for real-time telemetry data collected at Pellicer Creek. Telemetry data now permanently receives RFU data.

8.1.2.7 Differential Leveling

The GTM research staff completed the annual task of measuring the elevation of the sonde in Pellicer Creek 06/24/2026 09:06-09:42 and 06/25/2026 08:34-08:53. The team measured the change in height from a reference benchmark and three positions on the piling holding the sonde. The orthometric height of the sonde tube pin position is used as the station offset when calibrating the depth sensor for the sonde. The orthometric heights of the positions can also be used to determine if the piling holding the sonde is moving vertically. The data sonde depth/level sensor offset was updated to -1.073 m from -1.068 m. Corrected all level data collected 06/25/2026 09:00 through 06/29/2026 13:45 to match new offset.

8.2 Weather Station

8.2.1 PAR Sensor Issues

The weather station has been experiencing elevated night-time PAR values. The elevated readings occur intermittently throughout the quarter, but the frequency increased and included elevated daytime readings beginning on September 18, 2025, 21:30 and ending on February 27, 2026, 9:30. The cause of the elevated readings was unknown. The PAR sensor was evaluated by Campbell Scientific and replaced under warranty.

A new PAR sensor was installed on February 27, 2026 and appears to be working properly.