Ozone lowering ORP values
My tank is a 150x50x50cm tank, with a 10mm glass. It is partially planted and with Amazonian fauna, including wild discus. I have two canisters (Eheim 2215 and 2217) inject CO2, regular fertilization using EI methods and a Chirinos Dr sterilizer. Recently I bought an ORP meter, e pen like one, and realized that the OPR values are lower than the recommended (i.e. 200mv to 400mv máximum). The values barely pass the 100mv. As the aquarium is well populated the organic matter tends to accumulate and lower ORP values make difficult to degrade it, especially in the substrate.
Because this I add a Weipro ET-50 ozonizer, that from between 5 to 50mg/l. Despite this, the ORP does not goes up, and sometimes seem to lower it. I tested the tap water, and the ORP meter gives values above 400mv, but after adding the ozonizer the values goes down instead to up.
Does anyone have an idea about why this may be happening?
Thank you all!