New tank 1st fill

[gregzz4]

Have you ever tested the TDS of your tap water ?
Maybe your LFS could test it for you

Do you have any on-going algae issues in your 14g ?
If not, you're probably OK without RO or RO/DI, but I prefer to use a system for my water, even though my tap water is only 8ppm

Even if your TDS is lower than ( for example ) 100 in your area, what exactly are you getting 100 parts of ??? Arsenic, copper, sulpher ... there's all kinds of stuff in city water

Just my 5 cents