It looks like it's just beetroot powder, likely you're using it for the nitrate content? There shouldn't be any issue at all taking it with AlphaMax XT. For nitrates and endurance, you really want at least 400mg nitrates. It doesn't look like the beetroot powder in Superbeet is standardized for nitrate content, and even standardized beetroot extracts I've seen only have 1.5-2.75% nitrates, meaning you'd need ~14.5g of beetroot, and it's possible that the product you're using has less than 2.75% nitrate, which is what the above dose is used on (400mg nitrates from a 2.75% extract).