About a year ago I tried the BDR cones both #3 & #4 under my cdp and didn't like the presentation at all. Next came sand bags under the unit. Both trials were with weight on top of the unit. Had much better success with an inflated inner tube but thats just my system...
It would appear that points or isolation devices of any sort are very system dependant and I would try before you buy if you can. If not buy used so you won't take a big hit if you have to re-sell them.
It would appear that points or isolation devices of any sort are very system dependant and I would try before you buy if you can. If not buy used so you won't take a big hit if you have to re-sell them.