Krowne S25-123 Chlorine/Sanitizer Level Test Strip Kit with Color Coded Chart for Restaurant Hotel Cafeteria Catering Service | 100 Piece Per Bottle | 0-200 PPM Test Range | 3.0"L x 4.0"W x 0.5"H, NSF

I regularly make my own chlorine bleach. Sodium hypochlorite (household liquid bleach) degrades over time and has a shelf life of about 3-5 months. Rather than stock up on bleach only to have it deteriorate over time, I buy pool shock (calcium hypochlorite) and use it to mix up a fresh batch of bleach as needed. I not only have the ability to store extra bleach without having to worry about the shelf life, but I also save a lot of money - a 1 lb package of pool shock is about $4, which can make A LOT of gallons of bleach. I wanted to test the strength of my bleach after it was diluted in a gallon of water to make sure the concentration was correct. I suspected that the most recent gallon I made was not strong enough, and I used these test strips to confirm my suspicion. After adding a bit more calcium hypochlorite to the solution, I was able to get the concentration correct; the test strips were noticeably darker and easy to read. (Just to be clear, I was testing the gallon of water that I'd added bleach to, not the bleach directly). Keep in mind that these test strips are not designed to test chlorine levels in tap water; if that's your purpose, then you need to buy a different product; this type of test strip is designed to measure levels of chorine in different dilutions (added to water) so that you know there is enough to sanitize or disinfect surfaces. For most microorgansims (bacteria and viruses), a level of 200 ppm is considered adequate. For killing mold, a higher concentration is necessary (I believe 2,000 ppm). The CDC has a really helpful list of how many ppm of bleach is required to kill various pathogens. I am very pleased with these test strips; they were easy to use and allowed me to verify the strength of my solution. I also found that I was able to rip a test strip in half so that I can make them last even longer. If you have any questions, I'm happy to try to help. Please consider leaving me feedback below if you found this review helpful.

Used for my pool, matches the readings my electronic meter shows. Useful.

I use these to check for remaining bleach after sanitizing my well or after changing whole house filters and sanitizing. Cost effective.

we had to shock our well with chlorine bleach. we were told we could detect chlorine with our noses, but to be on the safe side, we bought these. we were thinking that we'd never use 100 strips. wrong. while chlorine can certainly be detected by smell, these strips are very accurate and having used them, we would never want to rely purely on smell. we are ordering more. my second use was very different, so i am changing my review: i have used these strips twice now for testing chlorine levels following shocking of a residential well. the first time i was very pleased as they clearly showed the level of chlorine in the water when compared with the colors on the bottle. the second time however, they did absolutely nothing. there was no color change in the strips, although the smell of chlorine was evident. i checked for an expiration date, but there wasn't one on the label. i had a few strips left from the first vial, which worked well. quality control seems to be lacking with these strips. unfortunately we have already ordered more.

works as it should. this is for measuring chlorine ppm. DO NOT buy it if you are trying to measure pH balance.

I used these to chlorinate my well. Works very well. I was able to get an exact parts per million reading.

I see several reviews stating that they are using these test strips on plain water and seeing no effect. Tap water or filtered water won't have any effect on these strips since the amount of chlorine in plain water is just too little. The minimum concentration of chlorine that would be visible with these strips is probably about 5ppm and even then it would be a very very light shade of purple. The main description photos show the different shades of purple for the concentrations of 10ppm, 50ppm, 100ppm, and 200ppm. Anything under 10ppm or over 200ppm would require a different type of test strip. I've been using these test strips in my business for over a decade to measure my chlorine concentration of sanitizing solution and they work very well. The health department usually stops by a few times a year and they've never had any issues with us using these test strips. The only issue I have with them is that some of the strips stick together and you might accidentally get 2 strips when you only need 1.

These strips worked just fine for me to make sure there is no chlorine in my bottled spring water I use to make my wine

Works as described

Simple and classic but still the best solution. The plastic case is also good to avoid moisture

It works ok but give 4 stars because Hydrion Chlorine Test Roll is cheaper and working better.

Perfect strips

Works great to test the amount of bleach we clean with