Betta splendens (cronwtail, double tail, veiltail, halfmoon, plakat, elephant ear,deltas, etc etc) are very durable to a wide range of pH and hardness, s/he should be fine with those params. I'd recommend taking your time with acclimating the betta to your tank's water as its likely not to be the same as the water source your betta comes home in. Don't just flaot bag on tank and release, use drip acclmation or cup in small amounts of tank water every 5 minutes for an hour or so.
Be mindful that bettas are predatory fish and they may turn your cull tank into a lobster buffet. Every betta is different though. I've had one that could be kept with cherry shrimp just fine,.. I have another that killed large shrimp:ghost and amano as large as him (including his large tail fin) and guarded/ate his kills. Keeping the tank densely planted with plenty of hiding places for the shrimp that the betta can't get its head stuck in (chollo wood, and those little shrimp cubes may be betta death traps depending on size of item/fish). I'd recommend thick vegetation-especially dense mosses to increase shrimp survival.
Be mindful that bettas are predatory fish and they may turn your cull tank into a lobster buffet. Every betta is different though. I've had one that could be kept with cherry shrimp just fine,.. I have another that killed large shrimp:ghost and amano as large as him (including his large tail fin) and guarded/ate his kills. Keeping the tank densely planted with plenty of hiding places for the shrimp that the betta can't get its head stuck in (chollo wood, and those little shrimp cubes may be betta death traps depending on size of item/fish). I'd recommend thick vegetation-especially dense mosses to increase shrimp survival.
