Why can't I raise my alkalinity?

[Johnny bass07]

Ph 8.0 at night 8.2 day
Dkh 8
Mg 1350
C 450
N 2
P 0.03
1.026
Every time I try to raise my alk from 7 to 8 I get burned tips on half my sps.
The reason for wanting to raise them because the sps don't grow at all and are pale. When I have it at 7 I also have 0 n and 0.03 p
I start to raise it from 7 to 8 in a weeks time and also raise the nitrate at the same time. But every time by the end of the week they start to burn. I have nutrients there so I can't figure it out. I can dirty the water up and still can't run a higher alk. When I lower it back down to 7 the burning stops. If I add nutrients with it at 7 to try and get color or growth they just start turning brown. I don't get it.

 

[Ultra Aquatics]

Nothing wrong with running at 7, I run at 7 and have amazing growth. Your nutrients seem too low which definitely will cause burnt tips when you increase alk. Keep increased feeding and bioload if possible. If you need start dosing sodium nitrate or similar.

 

[Johnny bass07]

I dose potassium nitrate. I didn't think 2ppm of nitrate and 0.03 of p was that low. Where do my numbers need to be when I run 8 dkh? I can't get any growth or color at 7. I run orphek v4 for light so don't think light is an issue.