Sandbags I have no comment on. Actually searching for what you have!

Bladder: I bought a $20 one on Amazon in January and am very pleased with it. It reaches the bottom of my SpeedRucker, and I use a s-biner to clip it in. I like this one because the parts all detach, and it opens completely from the top. Easy to clean with the included tools. It's not U.S. made, but its thick rubber and I think it's going to last a long time.

WACOOL 3L 3Liter 100oz BPA Free EVA Hydration Pack Bladder, Leak-Proof Water Reservoir https://www.amazon.com/dp/B07BPQH2SB/ref=cm_sw_r_other_apa_i_mGUSEb05496R3