# GSA After Replacing Light. Need Advice. Shorter Photoperiod or Burst?



## I Should Go (Jan 15, 2016)

Hi Guys,

New to the forums here but I've had planted tanks for a few years now.

Basically I was hoping I could get some advice about what to do about the GSA on my plants.

I've had my 55g moderately planted tank for about 3 years now. Besides at the beginning, I've never had problems with algae except for a bit of diatoms.

Unfortunately this changed a few weeks ago when I replaced on of my T5 HO bulbs. The old bulb was about a year old.

Since then I've been getting GSA, mostly on the upper leaves of plants but also lower down on lower leaves of Java Fern and A. Reineckii.

So far I've tried increasing PO4 but that hasn't helped. The next thing I wanted to try was to reduce the photoperiod, since I've heard this can be effective.

What would help the most in this case? A shorter photoperiod or the same photoperiod with one bulb on for only a few hours? So a kind of noon day burst.

Here's some info on my tank:

55g 18" tall
Lighting: 2 x 54 W T5 HO on for 7 hours
DIY CO2 which gives ~ 20-25PPM
Dosing: 1/4 tsp CSM+B per week, 1/32 KH2PO4 2x per week, 1 tbsp equilibrium after 50%WC every week
Parameters: 5dGH, 5dKH, 20PPM Nitrate, 2 PPM Phosphate ( increased from 1PPM)


----------

