If memory serves the PB4Y carried something like 1800-2000 gallons of retardent.
CL415 and its older CL215 where both studied by USFS, BLM and serveral state fire agencies. The aircraft where found to be lacking in the design of the drop system. Also there is a shortage of lakes in the US with the needed, draft and length to allow the aircraft to operate, this is especially true in the mountain west and the plains areas of the state.
A lot of the older DC-4 and 6 tankers where let go, when the air tanker companys where allowed to bid on P-3 and C-130 aircraft that where removed from military service transfered to USFS or BLM and then sold to commercial operators. But there where some problems with the bidding and some accusations of fraud made. I don't know the compete story on this but from my understanding is that it got pretty ugly. The program was discontinued in light of the scandal.
As far as the retardent goes, don't know about the properties, but they do wash the aircraft down at the end of every day.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.