LFS advice on algea

[saltyair]

Learning in this hobby is non stop.

So a little back ground, I have a 180 gal mixed reef with a 65 gal refug/sump
250gal rated skimmer a large carbon/gfo reactor. This set up is now 4yr old.

I have not had any major algae outbreaks since year 1. But over the last 3 months I have had persistent patches of GHA that I manually clean during WC. (I do a weekly WC of 15gal with RO water)

3 months ago I made a desision that i still say was worth it. Others might disagree. I had a very sick YT I have had for over 5yrs (previously in a 75) The YT came down with a blood bacteria and was wasting away. I desperately tried to catch her no chance. So I dosed my tank with melflex for 3 days @ 3/4 first dose and 2 1/2 dose. After the three days the YT survived and started eating again after not eating for 10 days (she was fat) Total success saving the YT. I did lose a milli frag and had to trim a blue acro due to stn.

#1 mistake I also had trimmed my cheteo way to much, over 50%
#2 my old carbon reactor cracked and was not being used for 3 days - than 5 days due to meds.

I also had to stop carbon dosing due to meds. I had started carbon dosing 3 month prior.

- I have tested parm's weekly since using the meds

Before carbon dosing my NO3 was in the 20-30 range
PO4 was always around .25/ .5
cal - 400
Alk - 9
PH 8.1

After carbon dosing for a month and adding GFO
NO3 - 0
PO4 -0
Alk - 8
PH 8.1
Cal - 400

So I went to the LFS - has given me good advise 80% of the time. I asked why I have GHA in my DT - it has been growing since the meds. (3 months ago) I was assuming they were going to tell me to shut down the lights/ slowdown on feeding/ increase flow, maybe the bacteria hasn't caught back up to the bio load ect.

This is what they told me to do. Add more nutrients, the GHA is growing because your tank is @ 0 or close to 0 nutrients

They proceeded to tell me about fresh water planted tanks and that the combat algae is by increasing NO3 - a little research I did find that.

" There’s considerable anecdotal evidence that nitrates and phosphates do not cause algae in a heavily planted aquarium. In highly illuminated tanks with CO2 injection the dosing of these nutrients is considered essential to help prevent algae. If nutrient deficiencies occur, plants will leech ammonia/ammonium that can trigger algae outbreaks."

Also found a lot of issues with people carbon dosing and getting cyano outbreaks.

This suggestion goes against everything I thought we were to do to keep GHA from our tanks.

I do not have a overgrowth of GHA - I have a few persistent spots.

Was this advise crazy? should I shut down my GFO/Carbon, should I stop carbon dosing?

Any thoughts are welcome.