Spiral,

Rather than going 5 different directions about algae, focus on the dang
plants!
Take care of their needs.

The PO4 issue could be the test kit, you are relying all the issue on
that, that has NOTHING to do with BGA or outbreaks of algae unless it's
too low.

Tell me, anyone, what is the difference between 2ppm of PO4 and say
5ppm of PO4 regarding algae, will one cause algae ansd the other will
not? I've dosed 1-2ppm of PO4 in my tanks for oh..........about 15
years ..........where is my algae?

I'll tell you, it's not there and PO4 excess does not cause algae in a
well planted tank.

Now poor CO2, lack of NO3, K, traces, GH, PO4 etc sure
will...................

It';s simply much easier and straight forward for a new person to focus
on the plant's needs.

I am over playing the notion of NOT using antibiotics because it's an
easy solution to a more complicated issue.

KNO3 is what the tank is lacking, not antibiotics.

Blackout and antiobiotics merely kill what's there, it does NOT solve
your issue.

Ask your self this: why do I have algae?
Poor plant growth.

When the plants are growing well, you have no algae.
So focus on the plants.

Any plant can handle a 3 day blackout, if you fail to add the KNO3
back, the BGa will come back in a few days, if you fail to add the KNO3
doing the antiobiotic, it'll come back in 1-2 months, perhaps longer if
you feed more etc or somehow start adding more Nitrogen.

The blackout allows you to repeat the KNO3 test and shows you rather
quickly that the lack of KNO3 encourages a BGA bloom. It would have
taken me years to figure that out using antibiotics.............so
pills don't teach you much either.

Stay healthy and you don't get sick and need pills/algae fix, Copper
etc, so keep your plants healthy.
Rather than the quick fix, look at the long term solution, then folks
can get back to talking about plants and not algae .........

This is much easier and actually deceptively simple.

Regards,
Tom Barr