Too much phosphate ?

[Garf]

This experiment seems to indicate reduced algae growth at increased phos levels;
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3434001/
wouldnt this indicate that once a tipping point has been reached, you'll never get enough growth to reduce it ? Don't mind if I'm wrong on this by the way, but it's what it sais to me.http://i1269.photobucket.com/albums/jj597/Garf1971/368b24542eba0e55758dde7f554ed3a9.jpg (http://http://i1269.photobucket.com/albums/jj597/Garf1971/368b24542eba0e55758dde7f554ed3a9.jpg)
and therefore that after this tipping point is reached, if ever, you will need to reduce it artificially to promote screen growth once again!

[SantaMonica]

It's well known that lower P grows better and greener.

Higher P just grows darker and slower, but still reduces P, which eventually gets down the higher-growth level.

[Garf]

So, instead of people struggling with black screens, a shortcut could be "add a bit of GFO" to get it into the optimal range for macro-algae growth?

[SantaMonica]

Stronger light and better harvesting are probably better methods, which will remove more N too.

[Floyd R Turbo]

This might explain a zero growth situation I have on a large, neglected tank. 225g FOWLR, N and P through the roof. If I don't start getting growth in a week, I'm probably going to do a PWC or might try GFO for a bit, but going to give it a chance, maybe seed the screen.

[SantaMonica]

Might also be copper.

[kotlec]

What are general symptoms of copper presence in tank ? May be we can have FAQ on that ?

[SantaMonica]

No algae.

[kotlec]

Then copper is very bad for scrubbed tanks.

How to cure ? What binds copper best ? Poly-filter may be ?
Is there any good way to test it ?

[Garf]

Red herring

[SantaMonica]

If there is enough copper to kill scrubber growth, it would need to be removed by water changes or poly filters.

Low levels of copper, of course, do no stop scrubber growth, and the scrubber will remove the copper. But being a fish only tank, it might have been added.

[Floyd R Turbo]

The tank I refer to was completely emptied, substrate thrown, rocks soaked (tested before and after on 2 copper test kits, zero copper).

I cleaned the screen for the first time today (5+ weeks) and the slot was clogged with green, bits of green on the corners, and brown staining (no other way to describe it) on the rest of the screen. I will have to take a water sample next time I stop in and dilute & test it....off the charts, I bet.

[Pulse]

To get rid of copper? Don't get it in there in the first place, otherwise remove the source and then massive water changes.

[kotlec]

That was theoretical question :)