[Keekee]

I am having some macro algae in my tank and after certain period, some of them would just die off and left a fraction and they will start grow again.

I was told by the LFS that I should be harvesting them before even they die off to avoid toxic back accumulated back into the tank.

Is that true? Or I could just leave it until it dies?

Thx for helping!

[waterloomarc]

No you should harvest it before it dies. When it dies it releases all of the nitrates and phosphates and such back into the tank that it had taken out when it was growing. Prune it regularly and it won't die, and you will have an efficient means of exporting these nutrients from your tank.

[bongobrian]

Is this macro inside of your tank? when you have macros inside the tank they often reproduce when the lights are off, causing it to turn white and die. Why they do this I have no idea. It's better to have macros in a refugium where you can have the lights on 24/7 and keep the macros from getting sassy.