First of all -- you have plenty of company. I've done string dates with as many as 30 strings and only one or two basses playing pizz can really fill the room. Consequently, if you have a pizz sample with, say, 9 basses on it, it's easy to get a lot more action in the low end than you want.
Diagnosis
If you don't have a sub speaker, it's pretty hard to tell what's going on and the results may not translate to other systems / speaker configurations. Put another way, if your listening system doesn't "really" cover that low end, you may be frustrated because what's happening in that frequency may not be fully audible. Even a dirt cheap sub can help with this; you don't need to spend a lot of money to help yourself hear what you're missing.
Solution
I'm assuming you are talking about samples? If so, consider putting the pizz bass (actually arco bass too) on a separate audio stem with either no reverb at all, or at a minimum with a high pass EQ on the send bus. The idea is to keep any really low frequencies away from your reverb. At the risk of over-explaining, you insert the EQ before any signal from the bass hits your reverb, and shape the high pass so little or nothing in the low range hits the reverb. [edit: I am NOT proposing that you put a high pass EQ on an insert on the entire contrabass track, only on the send to the reverb]
It's not always that easy to fix and sometimes you really have to print the bass to audio and zero in on any notes that "bloom" too much.
Good luck!
John