Why does GHA only grow on my frag rack?

[Zeal]

Title.
I’m tired of having to constantly clean my frag rack. For some odd reason GHA only grows on this corner and on the other side. It can’t be lack of flow because I’m running a MP10 TSM mode at 100% and a Nero 5 at 2500 GPH as well...

getting tired of this frag rack

 

[X-37B]

If thats the only place it grows be happy.
Soak it in 34% h2o2 diluted with water.
I use about 50ml per gal.
It will kill everything.

 

[ajhudson15]

I have the same issue with mine. mostly sps tank with plenty of low. mine is magnetic ocean wonders rack

 

[PicassoClown04]

Me too! I did a post about it a while back. Did a full cleanse with scraping, tooth brushing, under fresh water, got it sparkling. It was green in two weeks. Then I shifted it to the right about 3 inches. No more GHA!!

 

[Zeal]

Me too! I did a post about it a while back. Did a full cleanse with scraping, tooth brushing, under fresh water, got it sparkling. It was green in two weeks. Then I shifted it to the right about 3 inches. No more GHA!!

I wonder what could be causing it... this rack has been here for almost 2 yearsb

 

[Opus]

Same for me. I have 4 racks in my tank in different flow areas and different heights and algae loves to grow on them. Even the bubble algae. Get very little growth on the rocks. My only theory is the cuc can reach the rocks easily but not the racks.

 

[Zeal]

Possible

Same for me. I have 4 racks in my tank in different flow areas and different heights and algae loves to grow on them. Even the bubble algae. Get very little growth on the rocks. My only theory is the cuc can reach the rocks easily but not the racks.

I wish I could get rid of that rack entirely. But gotta sell those corals first