Oxidizer Baseline and the Cloner's Proof of Sterile

Recently I realized it’s good to teach people about establishing a “24 hour Oxidizer Baseline” with their system between cloning cycles. This can take overnight, once you’re good at it, but the first time you need a couple days to ensure your system and water supply are able to be sanitized.

24 hour oxidizer Baseline involves establishing a low-dose concentration of oxidizer that isn’t completely eliminated in 24 hours. The goal is to spike a minimum dose one day, and the next day the oxidizer remains detectable. AGAIN, THIS IS DONE WITHOUT PLANTS IN THE SYSTEM. This test ensure everything is performing right, both YOU—the technician—and the equipment and water supply. It’s important you try this experiment during your next down-time with the cloner. You’ll need 3 - 5 days that the cloner is not being used to do this. The experience is priceless.

You’ll need plain Bleach (I like the 8.25% Sodium Hypochlorite) and pool test strips that contain both the “free” chlorine and “total chlorine” values, BOTH. These supplies are cheap.  

Establishing an Oxidizer Baseline:

1. Clean a cloner and PermaClone collars according to the PermaClone manual, along w/ the overnight circulation of 3 – 5 mL/gal Bleach.
2. Dump the cloner, and fill the cloner with your water source used in cloning. It’s important to use everything as you would during cloning since you’re also testing your waters ability to hold an oxidizer, too.
3. Add 0.2 – 0.3 mL/gal bleach—NOT MORE, NO LESS. circulate for several minutes, then test and record the Free & total chlorine levels. A picture of the test strip next to the color key is quick and easy.  
4. The next day, test and record the “free” and “total” chlorine levels according to the color key on the pool test strips.
1. Did the “free” Chlorine go down? Did “total” Chlorine go up? Are both values zero after one day?
5. If free chlorine went to zero, spike again with 0.2 – 0.3 mL/gal, circulate for minutes and test and record your chlorine values again. Repeat steps 4 – 5 until you can maintain the “free” chlorine overnight…this is when you know your techniques are good and your system is sterile. The last step is to test your water source.
6. Once you can go 24 hours maintaining the 1 – 3 ppm free chlorine, you have proven the system is sterile. Now you need to test your water supply independently. So dump the system using clean techniques and refill with the same water source. Spike with the same dosage of Chlorine bleach (0.1 – 0.3 mL/gal) used in steps 1 - 5. Circulate minutes, then test and document the values. Let this circulate overnight. The next day, your new water should be able to ALSO stay within the 1 – 3 ppm range overnight. This proves your water supply is not contaminated and that you can interact w/ you system in a way that doesn’t contaminate the system.

You may find that the first day the free chlorine does go to zero. This means there’s hypochlorite being used up by organic matter and you definitely need to go another day. The good news is the mere act of establishing the baseline sterilizes the system better all while building your technique around keeping sterile. Once you can go 24 hours w/o the chlorine going to undetectable levels, you can be confident the system is free of organic matter AND that you interact with the system in a “clean” way.