I am working on a 900 gallon system and am very undecided on how to heat it. I have watched videos on titanium heat exchangers and pex coils and have read some mention of heat pumps. Although any big build is quite an investment, I do not have an unlimited budget. I know some online heaters for these water volumes although great have a big price tag. I guess I am searching for reliable, safe, and most bang for my buck. I would love to hear any ideas!