Help pH keeps climbing!

[TWINTURBODOGO]

So finding out that the silica we're using WILL raise the ph so gonna start foliar feeding it once a week and eliminate it from the res.
That'll be our first step to figuring out what caused the ph spikes

 

[TWINTURBODOGO]

So after taking the silica out if the res in a water change.
The ph now plummeted like a rock down to 4.2 from 5.8 over night.
We mixed each nutrient one at a time at water change and checked ph after each and it did drop a bit.

It's been a battle keeping ph up this last week or so. No matter what we do the ph just keep goin back down.

Now we have what looks like calcium deficiencies on one and the other kinda looks like it's over watered.
We added another air pump to the res just in case, it hasn't changed anything though.

8-10-16
In our water change we used,
5g r/o
20ml cal/mag
75ml pro grow
20ml pure blend tea
10ml hydroguard
2.5ml Orca
Ph'd to 5.8, 816ppm.
Res temp 70°

Overnight it went up to 6.4 then down to 4.7 the next day.
It's gotten as low as 4.2 then we slowly bring it up to 5.8 over the day.
Ppm kept rising so not much nutrient uptake still.
Have topped off with another 5ml cal/mag twice now.
And just ph'd r/o water.