Do NOT use a Di-Chlor feeder. Di-Chlor as it breaks down results in chlorine and CYA--stabilizer. No stabilizer is bad, some stabilizer is needed, but too much stabilizer is a BIG problem, and with a Di-Chlor feeder you will get there before you know it. Then no matter HOW high you set it, you won't get enough chlorine in to stop algae growth.

Or, suppose you watch your levels very carefully. So your CYA level hits 50ppm and you don't want it to go higher. You have to stop using Di-Chlor and switch to Bleach/Liquid Chlorine or Cal-Hypo (which you MUST NOT put in the Di-Chlor feeder--very,very dangerous.)

But if your builder does not want to install an SWG, don't make him. Instead, don't let him install the Di-Chlor device, and plan on using Di Chlor dissolved in a bucket or Liquid Chlorine (don't say "bleach" or pool people go insane.) Then, find an experienced SWG installer and have THEM install the SWG.

I just use bleach myself, and sometimes use Di-Chlor, but if I had to make your choice, I would never put in the Di-Chlor feeder, yet would put in an SWG in a New York minute.