Greg wrote in message . ..
blank wandered in from the void and babbled something like:

Having managed to finally eliminate the hair algae in my 75 gal tank (no
CO2, low lighting), I added just 2mm of Seachem Flourish Iron to the tank
and within two days the damn algae is coming back. Is the fertilizer
encouraging this? Or am I barking up the wrong tree?

Woof woof!

Algae are not limited by iron ion your tank or anyone's.
The plants are.

A plant will become limited long before almost all algae.
I add 15mls 3x a week to my 75 gallon tank, I have no algae.
Surely the algae are not limited by Fe in my tank yet they do not grow
and this is consistent year after year.

So, I'd work on CO2 the most. Gas CO2 system? If not, get one. Xmas is
next week

My routine for a 75 gal with high light, 330w.
50% weekly water change
Prune, scrub, trim, clean FIRST! Then do the water change.
Dose the nutrients back in afterwards.

Add: 1/2 teaspoon of KNO3 for NO3.
1/8th-1/16th teaspoon of KH2PO4 for PO4
1/2Teaspoon of K2SO4 for K+.
15mls trace, for ll the traces.

Add KNO3/KH2PO4.Traces 3X a week at these dosages.

50% weekly water change and repeat.

Consider Rosey barbs, cherry bards, SAE's, Amano shrimps in mass.

Check your CO2 to be certain that you have 20-30ppm the ENTIRE time
the lights are on, so check pH 2x, once in the AM and once before the
lights go off.

Do this for 3 week
You tell me what you think.

Regards,
Tom Barr