Carbon dosing, ORP, skimming, and slime


New member
Hello all! I was hoping to get some feedback on some the the things I've been noticing on my tank. I decided to add vineager to my kalkwasser to increase the potency of my kalk and to add a source of carbon to increase my bio mass. My tank is young and as it matures my calcium and alkalinity needs are increasing slowly as my corals grow and as I add more to the system. Secondly, in spite of a refugium and an ATS my nitrates are creeping up to around 20 ppm. The vineagar is working as over the last 3 weeks my nitrates are trending down. I have noticed my ORP has increased from high 200 to low 300. Is this bc my beneficial bacteria is increasing? Another thing I've noticed is a thin coat of slime everywhere. Should I be concerned? Also my skimmate foam is in overdrive. Is this the product of increased nitrification?

I've been careful to add the carbon source slowly so not to drop my nitrates too dramatically and to not create a low oxygen environment for my tank. Any feedback is appreciated


New member
Wow! My water is crystal clear. Nitrates are barely detectable. My tangs are eating the slime algae like crazy when I clean it off the glass. I'm going to slowly back off the vinegar dose so not to drop the nitrates too low.


ReefKeeping Mag staff
Premium Member
How much vinegar is being dosed daily?
How is th pH holding up?

The ORP would be lower with less NO3( an oxidizer). However, the heterotrophic bacteria that metabolize the acetate from the acetic acid in the vinegar take ammonia( a reducer ) in a one step process without oxidizing it to nitrite or nitrate . Thus , the process lowers nitrate production from ammonia oxidation and removes the ammonia leaving :bacterial biomass which also uses phosphate,water and some CO2 which could raise the ORP. Decreased pH will also result in higher ORP.

Is the slime green; if it's white it may be bacterial ;indicative of a bit too much organic carbon.

I've been dosing vinegar and vodka for about 8 years now . It does really well keeping NO3 and PO4 low even in a heavily fed system. I also use kalk dosed independent of the carbon dosing .


New member
Amount of vineager is not measured per se. I have worked up from approximately 150 ml to about 500 ml. This is mixed with kalkwasser and then diluted into 10 gallons of RO water. This is the volume of my ATO reservoir. Now that I've started seeing slime I'm weaning back off. It is a white slime.

My PH runs 8-8.3. Alkalinity runs 7.5-9. My tank is in the family room and observe it frequently. I also monitor parameters frequently. I have noticed my coral color to be more vibrant and the water is more clear. The sand seems to be cleaner as well.

Thanks for the chemistry explanation, TMZ 😀. I'm going to have to look back at the nitrogen cycle and read more to fully understand what these reactions