Mixing Drive Types on a Smart Array controller (Quantum and COMPAQ)

I have a Proliant ML370 with a Smart Array controller.
This system is a little over 3 years old and out of warranty.

I have 6 Ultra3 SCSI 36GB 10K drives with one configured as a hot
spare.

One of the drives keeps failing, but if I pull it out and reinsert it
it works for a while. COMPAQ is of little help regarding this issue.

We recently lost a second drive, so I had to immediately procure a
replacement. I found one locally, but after purchasing it, I realized
that it was a Quantum drive in a COMPAQ housing.

I was able to install it, but since it's the hot spare, it is not
currently in the array.

It fits the same specs, but when I use the array configuration
utility, it has a different firmware and model. The model does not
say COMPAQ unlike the other drives.

I have had problems in the past mixing drives from the same
manufacturer in an IDE RAID configuration, so I am worried that when I
need this drive to work, it will not!

Can anyone please tell me if I should return this drive and get a
COMPAQ one (for about double the price)?

Thank you,

D