Running Blues only?

[NanaReefer]

40B/20L sump, in sump skimmer, LR/Chaeto Fuge. 11wks old. NO2/NO3 and ammonia all read .0 PO4 0.02

I'm having an algae issue with my SB. No where else. Little tufts of what might be GHA, everywhere on the SB. Regular bi-weekly 10g WC, 2 small fish, a Scarlet Hermit and assorted snails.

In 5yrs reefing I've never seen this before, so I'm very stumped how to treat.

I've been running my (first time user) LED's whites at 20% max 5hrs a day for the last week. No effect on the algae.

So today I'm shutting down the whites totally. Running the blues as have been at 50% max (ramping) for 10hrs. My concern is, will my corals be ok?

Please LMK as I really want to rid my tank of this crap

 

[NanaReefer]

Bump!

 

[mike007]

You have to be getting nutrients from somewhere If you are having nuisance algae Issues. You might want to have your water tested by another source. 9 0ut 10 times I find that these Issues are caused by overfeeding whether that's fish food or liquid coral foods. Most all of them contain lots of phosphates which will fuel the algae. Even though your test might be showing low phosphates the algae may be consuming it to fuel Its growth.