Our old 250k BTU heater died, so we bought a new Raypak Lo-NOx 400k BTU gas heater (less than $2k online). We upsized because from what I had read, bigger is better with respect to pool heaters. We maintain the pool ourselves - hubby handles maintenance, I handle the chemistry. So far we've made a pretty good team, but installing the heater was a little beyond our skill level. So we called the pool guy (relative of a relative) for installation, and he says that while we got a great pool heater, our filter isn't big enough to support it. We have a Hayward Star-Clear Plus cartridge filter - 90sf. He says we need to upgrade to a DE or sand filter - 48 sf. Does this sound right? He says that the heater won't get enough water pressure with our existing filter so it won't fire up right. I don't think he's trying to pool-store us, but I just wanted to get another opinion. Thoughts?
If we do upgrade our filter, we'll be getting a DE over a sand filter. Luckily, we used to have a sand filter, so the back wash system is in place. Any recommendations on DE filters? I'm just beginning this new line of research, so any direction would be much appreciated. He recommended the Pentair FNS. Thoughts?
Thanks in advance!