Is there a way for a Hydros controller to vary the speed of a DC return pump based on an input? For example, if I have a flow meter on my return line and want to vary my pump speed so that it always maintains 750 GPH can I do that? I swear a saw someone mention in a forum somewhere that you could use a liquid level sensor to do this and that would be even better but for the life of me I can't find that information now. Any help is greatly appreciated, thanks!