Performed cooling maintenance on one straight cool system. Checked all electrical, mechanical and performance of the system. Cleared and treated the drain line and washed the outdoor coil. Media filter is not too bad but will need to be replaced before Summer. The homeowner said he would order some new filter and replace it asap. I did find that the system does not have a water safety switch. No other major issues found. Presented options to have a water safety switch installed and the homeowner agreed. Installed a water safety switch on the secondary drain line. I cycled power at the thermostat and the system is operational at this time.