I've owned/maintained an 18'x36' vinyl inground w/diving board for the past twenty years. Admittedly, I've struggled some each year with keeping the water balanced, and low in algae. I used a DE filtration system.
A few days ago, I completed the conversion to a salt system (CircuPool Core55). I had worked to get the water 'balanced' prior to completing the installation, the hardness remains low (about 50). Thus, I arrived at TFP to learn the proper way to increase the hardness. So far I've found some mention that w/vinyl liner pools it's not an issue. So, now I'll start reading whatever I find on the subject.
Now with a growing number of grandchildren wanting to use the pool, I've got to learn the proper way of maintaining a safe/sanitary pool.
A few days ago, I completed the conversion to a salt system (CircuPool Core55). I had worked to get the water 'balanced' prior to completing the installation, the hardness remains low (about 50). Thus, I arrived at TFP to learn the proper way to increase the hardness. So far I've found some mention that w/vinyl liner pools it's not an issue. So, now I'll start reading whatever I find on the subject.
Now with a growing number of grandchildren wanting to use the pool, I've got to learn the proper way of maintaining a safe/sanitary pool.
Yes, a little learning curve but you'll get it in no time. The link below is a great place to start. Make sure you have a TF-100 or Taylor K-2006C test kit. Everything hinges on one of those. As for the CH, it's true that vinyl basically requires no calcium like a plaster pool since there is no plaster to erode from the shell. For swimming, it's important that the pH is within range (7.2-7.8), you have some stabilizer (CYA) to buffer the chlorine, and of course the chlorine itself, ideally balance to that CYA as noted on the 
