The 22-year-old Henri van Breda has been charged with the murders of his mother, father and brother at their family home on the secure estate in Stellenbosch in January 2015.
His sister, Marli, who was 16-years-old at the time, survived the attack.
Van Breda has pleaded not guilty to three charges of murder, one of attempted murder, as well as defeating the ends of justice.
Security manager Marcia Rossouw told the court that while there had been four activations on the night of the murders, they were not "true alarms", but instead could be explained by a power dip.
Rossouw, who has been working at the upmarket estate since February 2014, testified that when she started, improvements to security needed to be made.
The electric fence was upgraded in September 2014, while additional cameras were installed in 2015, but not as a result of the murders, she told the court.
Rossouw said one camera could turn 360 degrees, while the other can zoom in from 800 meters.
Cameras were placed at all the strategic points, as well as at the gates, while an infra red camera pointed towards the river.
She said the estate had two security routes, one inside the estate and the other along the perimeter.
She told the court that patrols that night had been completed as required.
The Van Breda house was located in the middle of the estate.
The R44 road runs past the estate, while the Protea hotel, two farms, an airfield and a municipal field are adjacent, she testified.
Rossouw said she had found out about the incident when a police officer sped up to the gate.
"A security officer accompanied them, and another one met them halfway."
She told the court she had "immediately requested a security officer to check every centimetre of the fence to check if there had been any signs of entry".
She also requested camera reports. Security on the estate was tight and homeowners could only enter the estate with their access cards.
She said sometimes homeowners would let others use their access cards, "but this practice was not allowed".
On the night of the murders, 18 people came in and out of the three gates to the estate.
All had had access cards. "Residents would report noises or anything out of the ordinary, but there was nothing on the night of attacks," she further told the court.
Rossouw said there was nothing in their records that night to indicate anything suspicious.
Defence advocate Pieter Botha was able to pick holes in the security system, however, and managed to get Rossouw to make several concessions during cross-examination.
Activations to the alarm system can be seen in a control room in Parow, after which a security officer is informed and checks, and the system is reset once the issue has been resolved.
Botha argued that if a branch was placed on the fence and the alarm activated, a person could climb over while the patrol officer was on the way and until the alarm was deactivated.
Rossouw conceded it would be possible to gain access this way, but said a camera would have picked up if a person had breached the fence.
Judge Siraj Desai asked if there was a possibility a tunnel could be dug under the fence, but Rossouw said there was no evidence of that, no footprints or broken bushes, or signs of a hole being dug.
She said a person would have to dig deep and would face the "possibility of being shocked".
Botha also focused on a 2012 report compiled by the company responsible for security at the estate, Thorburn security.
It listed a number of problem areas, "which were problem areas that night".
He pointed out that only 35% of the fence was under camera surveillance and if the fence was breached it took between five and eight minutes for a patroller to arrive on the scene.
Rossouw disputed the reaction time and told the court it was in fact four minutes or less.
Botha said there had been a security lapse when a journalist accessed the estate and took photographs of the house.
Botha said he had seen the reporter taking pictures from an unmarked car. Rossouw accepted that this was not very difficult to do.
Botha also referred to past burglaries and theft at De Zalze and said access had been gained by breaching the fence near the river entry point. The trial continues.