Parts Washer Help

[wraprail]

Hey all,
I have a solvent parts washer, the standard drum type (15 gallon drum) with the pump submerged about halfway down the tank. I recently cleaned it and got rid of the old solvent which was no longer any good. I got 5 gallons of Gunk brand solvent from Napa and it barely covers the pump. I don't really want to add more solvent (5 gallons was over $100) but i'm starting to suck air so,
I can probably throw a couple large rocks in the bottom of the tank which would raise the level but have never seen this done....
Or what about adding a couple gallons of water? Would this work? As long as the water level stayed below the pump?
Has anyone done this or heard of it before?

Thanks in advance..

[ETsC10]

IMHO, I think the rock idea is better (as long as it doesn't interfere with the sump). If you dilute the solvent and it turns out to be no better than plain water, there's not turning back and it would be wasted.