Gfo & chaeto

[ReeferDave01]

Since starting using gfo about a month (1 cup for about 300 gallon system) ago I've noticed my Chaeto has reduced by half the size and doesn't seem to be growing as vigorously as before. I haven't changed anything else. Is there anything I can do to encourage the growth more aside from cutting down gfo? I have the lights on about 12 hrs for Chaeto a day counter cycle from main tank. Phosphate is 10-12.

 

[oscargrumete61]

Take out the gfo is taking all the nutrients.it is not growing because is lacking

 

[teller]

Even if you add trace elements, like iron and others, or nitrogen sources your chaeto growth is already limited by the gfo: it would be useless.
If you need to keep some gfo why not use just 1/4 or less and see how the system reacts in terms of chaeto behavior, phosphate and nitrate levels. Then, after some weeks or a month, act according to the results.
Just don't let the macro algae die.

 

[Randy Holmes-Farley Verified Community Expert]

I agree the GFO is likely dropping phosphate to limiting concentrations. If you want it to grow more, use less GFO, or none.