Nitrates too low.

[Clownshow]

I left my tank with my mom when I went on vacation for two weeks so I covered the tank to keep evaporation down so she did not have to top off the water as often, but it caused a massive nitrate spike; about 80ppm which caused hair algae. I have been home for two weeks now and I got my nitrates down but now they are 0ppm. Is there any way to keep them a little higher but not too high?

 

[SMSREEF]

-Take protein skimmer offline if you have one
-Feed more
-Dose nitrate (I dose sodium nitrate)

 

[Clownshow]

-Take protein skimmer offline if you have one
-Feed more
-Dose nitrate (I dose sodium nitrate)

Should I take my surface skimmer out? I mostly just use it for flow.