In a way you are right. Several studies have shown that AAS-induced growth is enhanced by its aromization to estrogen which in turn causes water retention. (This is why cattle are given Fina + estrogen to fatten them up). The other pathway contributing to water retention is the renin-angiotensin system in the kidney. The general theory is that estrogen might increase local IGF-1, and the subsequent increase in circulating growth hormone then increases your strength. For this reason, if strength/mass is your primary goal, skip A-dex (which blocks the enzymatic conversion of AAS to estrogen), and go Nolva, which will allow the estrogen to be produced, but will block it at the receptor level.