1. The pipe from the pool filter to the pool must been devided. The heat exchangers are now connected between the two open pipe ends in series or parallel *.
In this case the pool heating takes place with the pool pump. It should be noted that the pool pump during the day is about 8 - 10 hours running and also in this time the pool water filters. If you do not want this, the 2nd option is the better solution for you.
2. The whole system runs with a second pump (circulation pump). Thus, you can use the pool filter pump according to your desired times and the second pump is used only for pool water heating. For this purpose, the pipe from the pool floor or floor cleaner is usually provided with a T-piece and connected to the second pump. The pump outlet goes to the heat exchangers and their outlet then goes into the pool.
Depending on the structural conditions, this can be connected directly to the pipe which goes to the inlet nozzles, or a separate pipe is laid directly into the pool. This sounds bad, but a circulation pump can also be used with only a 32 mm tube.
* When installing more than 2 heat exchangers, a parallel connection is required from my experience!
SAFE - LOW-MAINTENANCE - COST-EFFECTIVE