Total chlorine is the sum of your free chlorine (the good kind) and combined chlorine (the bad kind).
Total Chlorine FAQs
What is the purpose of total chlorine?
On its own, total chlorine means nothing. It’s a metric that exists purely to help you measure your combined chlorine, which is the “bad” kind. Combined chlorine plus free chlorine equals total chlorine. Free chlorine is the good stuff that’s available to sanitize your water. Combined chlorine is the gunky part that’s mixed up with contaminants like bacteria. All three numbers matter to help you keep track of what’s going on in your pool chemistry.
How to check your total chlorine
The simplest way to check your total chlorine is to follow this formula:
Free chlorine + combined chlorine = total chlorine
Lots of affordable tests can tell you total chlorine results, but keep in mind that you aren’t seeing the whole picture. Clean water will give you a combined chlorine reading of zero — then you can invert the formula to find out how much free chlorine you have left (total chlorine — combined chlorine = free chlorine). But let’s say you don’t have clean water, which might be why you’re testing in the first place. In that case, knowing your total chlorine reading won’t tell you much at all. Combined chlorine and free chlorine won’t come out as separate measurements, so you’re left without a clear answer.
This is an easy intro to the Taylor K-1000 Basic kit, which measures total chlorine and pH.
How is total chlorine used?
Total chlorine really just serves to help you identify how much combined chlorine you’ve got left in your water. When free chlorine gets low, it needs to be replenished to keep your pool properly sanitized. Too little free chlorine, and you’re looking at some nastiness: green water, stinky smells, plus all the unsavory physical effects of a dirty pool, like middle ear infections.
What should my total chlorine level be?
You want your chlorine levels to be exactly the same as your free chlorine levels, which should be 1.0 to 3.0 parts per million (ppm). If your chlorine levels are too low, you need to add a sanitizing solution like shock. If your chlorine levels are too high, you’ll need a neutralizer. You can also just expose your pool to some sunshine and swimming (once readings have dropped to a safe level) to help rebalance.
Is a high total chlorine level bad?
It depends. High levels can mean one of two things: a lot of free chlorine or a lot of combined chlorine. Either way, you want to get your chlorine levels to 1.0 to 3.0 ppm, and you’ll need to sanitize or neutralize to reach that level.
What is the difference between free chlorine and total chlorine?
We never get tired of this question. Total chlorine is made up of free chlorine and combined chlorine. Free chlorine is the good stuff that sanitizes your pool (because the chlorine is free to handle the icky stuff in your water). Combined chlorine is tied up with contaminants.
The Stuff You Need
We don’t do affiliate links, FYI. Anything we’re recommending is something we’d use to monitor our pools, too. If we start doing affiliate marketing, trust us, we’ll mention it first.
Cheap, reliable test that checks for total chlorine:
This test doesn’t check for free chlorine, but it’s the cheapest way to test total chlorine. It’s your call on whether this test is worth buying on its own; we typically go for test kits that give multiple readings.