Thanks for the info bbradbury. I feed NLS theraA pellets every 3 days. That shouldn't be enough to much up my water though, right?
Note that bbradbury keeps natural tanks, and I've always observed he gives advice specific to that style; regardless of the actual style of the person he's replying to.
With your stated EI dosing, CO2 supplementation, faster plant growth, and weekly water changes, you have *much* more leeway when it comes to avoiding nutrient buildup as a result of feeding. Even ignoring that, I'd say your feeding is conservative.
In my experience, even phosphate levels up to 30ppm from feeding and fertilization have no effect on staghorn (at least my staghorn).
The water out of my tap is showing phosphates so im guessing thats what is the main culprit.
Now this phosphate I tend to treat separately. A ppm or two seems ok, and I get 1ppm out of my tap. However, I've spoken with multiple people who have 4-5ppm or more who had chronic, unsolvable algae problems until they either used another water source, or used a phosphate reducing media. Not all people with high phosphates out of the tap experience this, but it does seem to increase the probability of problems.
Exactly why this is, I don't know. Perhaps it's an alternate form of phosphate that behaves differently. Or, since it's an undesirable contaminant for tapwater, high phosphates may be a sign of other contaminants and poor quality overall.
So how many ppm comes out of your tap?
Though even if it's high, I would definitely try all other options first, as getting an RO system or using consumable media will cost you.