Ok, here's my setup - 4x20 panel on the roof, standard 1HP run of the mill Hayward pump that typically runs on a timer. Last year I relied on manual control of the system to maximize solar gain, but I've decided to automate things this year...but I'm debating between the three automation systems in the title.
I want the system to be able to override my timer, a key factor for me. We pay time of use for our electricity here in Ontario so daytime (peak) power is signifigantly more expensive, so the timer typically focuses the bulk of my water turnover time overnight during off peak times, but the solar automation needs to be able to override the timer to actually circulate water through the collectors through the day when the controller determines it's worthwhile.
Initially I thought only the "Aquasolar TC" had the ability to override the pump, but I've discovered, if I'm reading things correctly, that it's little more than a glorified version of the GL235 with a built in timer, but the GL235 CAN override teh pump as well, it just doesn't have the built in timer? And the "Aquasolar" is basically a bare bones model without the high voltage (aka, pump control) relay?
It's rather confusing. Basically, if the GL235 is capable of powering on my pump whenever the solar panels are in the loop, this is the system I am thinking I'm going to opt for, but I need clarification.