Hair algae problem...need help..

Hey guys, I have a 25g with 12g sump reeftank that is 2 months old. My daitoms had disappeared really fast but suddenly since past 1 week im getting massive hair algae problem and daitoms also started coming. I tested and the results are:
PO4 - 0
SI - 0
N03 - 0

iv read that increasing the mag levels can kill HA.

Need suggestions. ASAP. here are some pics:


my new 25g reef tank with sump - YouTube

 

Are you using only RO/DI water?

Do you have a sufficient clean up crew?

Consider a ATS if this turns into a chronic problem.
Some urchins are extremely good at eating GHA as are some snails such as Astraea and Turbos.

 

ok... But i dont have space for ATS at all.... should i increase mag levels?? iv read it kills HA

 

In a 2 month old tank I would not be too concerned, it may just die off on it's own.

Raising Magnesium is considered a treatment for Byropsis, more than GHA ,and you have to raise it significantly which can be harmful to members of your CUC specifically snails.

Personally as long as your using RO/DI and not over feeding I would see if it's just part of the cycle.

Might want to look in Phosguard or similar products as well.

 

but my PO4 is 0....will wait though....

 

Go lights out for 3 days, no light at all. Your soft coral will survive.

 

I have already added sps lps......