Because the 3" tablets have cyanuric acid. Eventually, the cyanuric acid from the tablets will accumulate in your pool which will require you to drain it.
If you are on water restrictions, city charges a lot for water (or you are on a tight budget), or use a well for water... this can become a problem.
If you have cheap water and don't mind dumping and refilling the pool every so often... then you can use the tabs.
If you actually do the math, with the markup on the chlorine tabs along with the fact that you are going to spend money redoing all your chemicals (because when you drain for high CYA you lose everything else in the water and have to start from fresh...).... liquid chlorine is WAY cheaper.
Liquid chlorine only adds salt to your pool (so do tablets). But it does NOT add cyanuric acid unlike the tablets.
Thanks for the info, I am going to keep using Liquid chlorine. I will keep an eye on the cyanuric acid to keep it at 4 ppm, right now it's at 5 ppm. I am going to buy my liquid chlorine once a month so I will need buy 4 boxes and hope that will not expire before I use it during the month.Don't get me wrong, cyanuric acid (conditioner, stabilizer... same thing) is not to be avoided at all costs. You need 30-50ppm to keep the sun from burning off your chlorine. But once you get to 50... you don't want to keep adding because it will get to the point where your pool turns green and you are forced to drain because of high cyanuric acid. That's why we keep things simple and add a known amount of cyanuric acid to the pool, and then just use liquid chlorine from there to keep it from rising. You will notice that your cyanuric acid will drop a few parts per million per month, so you may want to throw a tab in a floater every other month to add back what's lost, but you definitely do not want to overload your pool with cyanuric acid from the tablets.
Sorry I mean 50 ppm going to get it to 40 ppm and keep it there 4.Can you clarify... you said you are keeping your cyanuric acid level at what? You said 4 or 5? Do you mean 40 or 50?
You can buy liquid chlorine a month in advance. I buy a few months worth in advance. The only concern is storage. Make sure to store it somewhere cool and away from the sun's rays and heat, as these factors will cause your liquid chlorine to degrade significantly. However, if stored properly it should be fine and won't "expire" or "weaken" much over a month or two.
You will need about 1/4 of a gallon per day for your pool. If you want to buy 1 month in advance, that would be about 8 gallons per month more or less.
So you saying 50 ppm is ok just keep FC at 8 but don't let it drop below 3 or 4?Just remember that your free chlorine level should approximate the values shown in this table (based on current cyanuric acid level): FC/CYA Chart
For 40ppm, target a free chlorine of 7. For 50ppm, target a free chlorien of 8. Try to never let your chlorine fall below the minimum (3 or 4) and you won't have any issues with your water.