external overflow box

[coaltrain]

I am looking for a quiet overflow box, right now mine makes alot of noise. If I turn down the pumps it goes away. So is there a good quiet box or do I just need a larger box. I have a 150 gal tank with rio 2500 return pumps and two overflow boxes right now. Should I stick with two or can I go with one and what is a good brand of box? The key is I'm looking for quiet. thanks

[Drae]

Cpr cs series (constant siphon) are the only ones if ever use. They are completely silent and work great ime *Drae*