The KH is certainly not the culprit for the algae. Reduce your light cycle
or start dosing CO2 and ferts, is this a planted tank?
What is your current light cycle?
Size of tank and ammount of light?
Fishload?
Water changing routine?
PH?

Answering all or some of these questions will lead to a better diagnosis of
whats happening in your tank.
--
"In the beginning, God said the four-dimensional divergence of an
antisymmetric,
second rank tensor equals zero, and there was Light , and it was good."


"Dave S" wrote in message
...

"Iain Miller" wrote in message
...

"Dave S" wrote in message
...
How do I reduce a KH of 150mg/L to 80-100mg/L?

Use water filtered through peat or use RO water for your water
changes.Alternatively stuff some bogwood in the tank or peat granules in
your filter.

Thanks for that!

Before you do this, why do you want to do it? Unless you have specific
fish that require it (and most don't) I should leave well alone (!)

I have a lot of algae on plant leaves, and as all the other water
paremters
are OK, I'm trying to identify the reason.

Dave