so the visual indicator would be nuisance algae?

Yup, usually GHA.

Maybe you should have an option for algae scrubbers, although I suppose that could fall under macro-algae even though it is micro-algae?

I had an algae scrubber running, although I recently took it down due to a bunch of plumbing changes I made for the new fuge. I am growing macroalgae, (several kinds), and also have a bag of GFO in the sump. The macros will also serve as fish food.

When I started my new tank, I placed the live rock right out of the box into the tank as I am of the belief that by doing so you keep all of the live stuff like sponges, corals, inverts etc. on the rock and the critters that live in the rock.
The down side is an algae problem and high phosphate.
The sea hare dealt with the algae and with water changes and a Phosphate lowering product (in a small plastic bottle) that I bought from Ocean Aquatics, I was able to slowly lower the phosphate to acceptable levels.

see how quickly I forget...I had that in the 90's before I bought my first RO unit

I don't do anything.

I have tested for phosphates in the past and run phosphate removers but I never noticed a difference in the test kit results when I did so nor did I notice a difference in the tank inhabitants... so I quit.

I'm pretty sure I have phosphates and nitrates out the waazoo but until my corals start screaming for help I won't do much about it :mrgreen:

More people should do this, DSB's are bad.

Just my 2 cents..

Dsb's are good

just my 2 cents...:razz:

lol

I'll share my own experiences and the reasoning for asking what others do.

I run a tiny little ball of chaeto in an aquaclear lit by 2x9w PC's. This is for a 115g cube so it probably really has a negligible effect on NO3/PO4 pulldown.

I've never been able to get a reading higher than the lowest category on a chemical based test kit. So for some this means "zero" and while others like the D-D/Merck it means "0 to 0.008" (which may as well be zero).

Don't have a lick of GHA in the display, although sometimes I will find some growing in the overflow eggcrate.

Most SPS I have exhibit very poor growth rates (or abnormal mortality rates). I was initially convinced this was due to phosphate but never having been able to establish a significant nonzero reading on any testkit (including the $300 Hanna colorimeter), I started reaching out to other explanations, including pathogens. The story of the last year though is that I am now starting to believe it's not pathogenic in nature ... so I'm coming home to the phosphate theory.

If I could establish that there is a difference made then I would gladly revert back to using GFO. And yet, when I ran GFO in the past, it never made a difference; nor did my brief (6 month) experiment with Zeo.

But so far it sounds like that for those who have noticed a difference with and without GFO, that the difference was enough to be profound, or at least, enough to actually notice a difference. So this is still confusing to me as to whether I may truly have a phosphate buildup or not.

Anyhow thanks all for the comments and thoughts. It is all very interesting to me.