Water Change with Canadian Springs?

[anglfish]

Hello you Experts out there!

I always do my water changes with RO water bought from any grocery store. Normally that is "Arrowhead Premium Drinking Water" (only ingredients are water and ozone and it says TDS < 5 ppm) whatever TDS means
Last two times I used Canadian Springs and since then I'm fighting a diatom bloom. All my water values are fine (ammonia, nitrite = 0, nitrate 0-5, phosphates 0.25, ph 8.2-8-3, salinity .023).
Now as I read diatoms at the beginning are normal, I still wonder and try to find the source of this. The reason why I wonder is because I had no cycle (no ammonia spike) as I used LR from an established 3 year old tank.
Couldn't find a silicate test kit so I'm hesitant to just get a silicate removing media. besides the only thing I've seen in the stores is Kent phosphate remover. is that the way to go?
anyhow... back to the scope of this thread.... now I start wondering whether the water I used could be the source of the problem. Please see details below... any advice is greatly appreciated as I have another water change planned for today.

Canadian Springs:
dissolved mineral salt content 210 ppm
fluoride Ion 0.1 ppm

Analysis (mg/l):
HCO3 136
CA 60
F 0.1
Mg 5
NO3 0.6
Na 4
SO4 58

I go for a run with my doggie... but I trust that this issue will be extensively discussed and resolved by the time I return...

hahaha I'm just kidding.

A million thanks in advance.