Bring a Hayward CAT 2000 pool controller into HA (cheaply)

I’m a member of a small community that shares an outdoor in-ground pool. I’m new to the pool committee, but I see that maintenance has been cheaply and poorly managed over the years. We just got a new Hayward CAT 2000 automated system to maintain our chlorine and pH, but it’s been problematic. (I think we don’t have cyanuric acid, so the chlorine feeder runs continuously and then trips the alarm and shuts off. I’m trying to wrest more control over our chemistry and testing. Also, power outages mean someone has to restart the pump in person.)
When we got the CAT 2000, the new pool guy originally offered it as a system we could control remotely, which is perfect because there are stretches when no one’s around to check on things in person. But then he decided against the remote feature because there were enough problems to fix up front. I know the Omnilogic remote system is an add-on that costs thousands, and I know the community won’t go for it. I see that the controller has a serial port (RS232), presumably to communicate with such an add-on.
Is there a cheaper ad-hoc way for me to gain remote access to the controller? A cable that can connect to it and allow me access? Or is any remote option dependent on Hayward’s own Omnilogic?