To help describe some things, there are two thermal valves to switch from main storage to Domestic Hot Water exchanger storage. A pv panel to supply power for pumps. A tempering valve to insure no scalding water is present at DHW faucets. A heat exchanger for pool,and one for DHW to insure no contaminants enter the DW supply.

 I still prefer drainback for freeze protection , and to make the filling costs cheaper.You'll also notice a pipe(not labeled) between the tanks, this should be slightly above the normal water level, to allow the two tanks to balance their levels..

 I also forgot to add a fill and overflow..oops, and didn't label the house heating circuits pump.
 For simplicity I didn't show any wiring.

 You are obviously mis-reading something my suggestion for using 1 heat exchanger was you COULD switch between the house heat circuit and the pool circuit IF you do not require both at the same time. You NEVER (ever) EVER!!!!! mix ANY water (or switch between pipes that use it)that could possibly contain contaminates with your DW system..PERIOD.

 System usage: PV runs pump when solar insolation is high enough to use the collectors(it's possible to add a mini-maximizer in that circuit). the system drains back (I neglected to add valves for that) emptying the collectors when not in use. Eliminating the need for anti-freeze.
Water is routed to the DHW exchange tank until tank temp is high enough, then switched over to main storage.(or you could have two totally separate systems). Heating is available for pool in summer, and heating the house in winter.