Holy crap! I have been using 170ppm TDS water!

[neoh]

I get 7-9 TDS out of my kitchen sink and don't use any kind of conditioner and let the water sit overnight with a powerhead and heater. I've yet to have algae - except in my planted tanks, it was a battle I suffered for a long time despite every effort and made me shut it down, afterwords I realized that I should of probably be using RO water.

So far in the marine tank, I haven't had any algae issues - but I do have an rodi system, that I don't use, but have some ro water stored in case of an emergency. I don't know, it's a fail safe thing for me.