Combined chlor value

[RonPace]

Something said on another thread prompted me to download a pool calculator app. imo, a waste of 5€ as it did not give me any info that I can get free from the internet. But hey ho, that’s life!
One thing I noticed though it had no provision to record a total chlorine reading, just free chlorine. My little tablet tester offers a total chlorine reading, but then I ask myself, is it important to know a pool’s combined chlorine? If it is over 1.5 of free chlorine, is it an indication of any danger?

[Teapot1]

If the combined chlorine climbs to more than 0.5 over the free chlorine its an indication of a possible issue like an algae bloom about to happen. Helps spot issues before they become bigger.

[Denniswiseman]

Combined chlorine is the chlorine that has already been “used up” to sanitize your water. When chlorine in the pool water comes in contact with organic material, such as algae,skin oils, urine or sweat, they react to form combined chlorine, also known as chloramines, which is the chlorine smell that people think is over chlorination but isn't
So total chlorine is a waste of time looking at by itself as there is no indication of the sanitising effect

[RonPace]

I understand that total chlorine value on its own is of no use, but with a known free chlorine value, the combined value can be calculated, and as teapot surmised, used to spot anything down the line.

My Scuba gives both values with the right tablets, I am surprised that an app that costs 5€ does not!

Teapot - thanks, but is it at 0.5 one should be worried? I have it noted on my pool house wall that it is 1.5 above free...indeed, I generally have 1 to 1.2 above. I am sure I would not have written 1.5 if I did not see it somewhere here...