In my opinion all of your other water chemistry is fine. I used RO water for a long time, and after adding ca/mg the PPM (700 scale) would go from 0 to 400 or so. My water is normal hardness with a ppm of about 300 (again, 700 scale). Now I use tap water and supplement ca/mg 1/4 strength and everything is just as happy and I'm using 1/2 the water and 3/4 less ca/mg.
You could do the same. Since your water is soft, I'd go with maybe 1/2 strength ca/mg to supplement. Before you mix anything in the water, let it sit out for 24 hours or use an air stone to bubble air through for a couple of hours to off gas chlorine and you should be good to go. Your water's PPM says 380 ms/cm which is 500 scale which equates to about 420 on the 700 scale. That's a bit high, and it would go up to about 600 just after adding ca/mg. So you may want to dilute your tap water by 1/3 with distilled or RO first.
Good to hear that it appears to be fine, but I'll prob start with 1/4 CalMag, too, and only if deficiencies occur.
Somewhere in this thread I wrote that I tested my water. It has about 180-190 ppm at about 20°C, but what exactly are those scales you speak of? Never heard of it before. Nevertheless, someone already recommended to dilute my water, but I really don't want to go through the struggle of buying and having to transport all those gallons. I'm short on finances and very lazy. Add to that the fact that you need to switch out the entire reservoir every 7-10 days which makes it even more of a struggle tbh. I really would like to just start like this. Also, I heard about people that used tap water with a way higher ppm than mine and they were absolutely fine.
By the way, luckily, my water doesn't contain any chlorine, only chloride. So the 24 hour sitting period is most likely not even neccessary and it's good to use right out of the tap.
