Thread: Chlorine testing

I’m now back from holiday and looking to order a big blue. I’ve checked my water supplier and they only add chlorine, and not chloramine so looking at GAC Carbon media, assume this is correct
Also, what are people using to test the chlorine levels out of the filter so you know when to change the media ?

You can buy a Hanna chlorine tester but don't buy a normal chlorine test kit, they're not sensitive enough to measure down to 0.02 mg/L which is the maximum tolerable level for chlorine/chloramine for koi; use the DPD4 test I put on my website several years ago in answer to the problem of detecting very low levels of chlorine/chloramine without having to use a photometer.

It will detect trace levels of chlorine or chloramine from a purifier that is nearing the end of its life, long before they become high enough to affect koi or it can be used to test a sample from a pond to verify that manual dechlorination has been effective.

However, some people recommend it without passing on the correct method and it's most accurate if you do it exactly as I describe:
www.mankysanke.co.uk/html/questions_answered.html
A typical supplier of DPD4 test tablets
https://www.ebay.co.uk/itm/154201052984

Thanks for the reply Manky Sanke, your link is excellent, I will follow the instructions.

Since my DPD4 method has been recommended many times without proper instructions on how to do it, can I please ask that if anyone does want to recommend it, could you please pass on the message that it must be done in the way I describe on my website to give valid results?

You don't need to remember the web address just tell people to Google:
Manky Sanke questions answered