Overkill

[Spat_si]

I'm just wondering if adding another filter onto my 55 Gal tank would be worth the money? The Filtration seems good right now but once my fish get bigger I'm thinking I may need more?

 

[Bol]

If your water is clean and your chemical levels are fine, then in my opinion, it ain't broke ... don't fix it.

You may later, tough to tell. I'd keep an eye on how your nitrates do as your fish get larger.

If it comes down to it, then personally I wouldn't add a third filter -- I'd replace one of the existing ones, probably the 125. (Of course, a 170 makes a pretty good filter by itself in a 20 or 29 gallon tank )