Huge trouble with nitrates

[hrdneglcry]

So I never have tested for nitrates. And they were the worst color on the Salifert test. I have changed 210 gallons on my 180 tank/120 sump. But the test still shows the worst color. I vacuumed the sand bed but there was no brown in it. I will keep changing water but having trouble figuring out why the nitrates are not falling. The filters are cleaned.

 

[hrdneglcry]

Looks like it comes out of the tap with high nitrates. Time to get
the RO going

 

[Fish Fan]

Looks like it comes out of the tap with high nitrates. Time to get
the RO going

Sounds like a solid move. For most locations, using tap water isn't a good idea