how does water quality effect fry

Hello I am new to the forum and breeding discus. I had the opportunity to get a proven breeding pair last month. Prior to Mother's Day they layed eggs, because that is a busy holiday at work I wasn't monitoring my water for breeding quality (from what I've read on the Internet). Typical parameters in my main tank is ph7.4 nitrite 0 ammonia 0 nitrate 5.0 temp 84f. I have kept them in my 20 gal med tank, there pH 6.7 everything else match the main tank, also TDS reading between 160s to 180s... So the eggs were layed and on the 8th they hatched. Again with that being a busy time for work I thought I'd just let nature take its course and when the holiday was over I'd have the time to do it right. Everyday I've been checking on the fry and there growing and growing. Now my question is what are the concequences of raising fry in "non ideal" water? I had only been doing water changes 2 to 3 times a week instead of everyday. And from what I read online my parameters don't seem idea and I'm using unfiltered tap water.