Redose in days, not hours
Mark II Stabilizer
A non-biocidal additive for metalworking fluid. It does not kill anything in the sump. It just stops the organisms already there from reproducing fast enough to hold their numbers.
It doesn't kill anything, and that's the entire argument.
Mark II Stabilizer controls corrosion, buffers pH, and affects the rate of microbial growth in a metalworking sump. Where it earns its name is the last part. A biocide kills, and gets consumed doing it. When its concentration falls below the effective level you get a bloom, a burst of fast regrowth, and the window to catch that with a redose is measured in hours. Mark II never kills a single organism. Organisms simply will not grow in its presence, so the population declines slowly, by attrition, over days. Recovery is just as slow, which is why the redose window runs to days instead of hours.
Many fluid manufacturers already build Mark II into their own formulations. Nothing to add at the tank. Call BioTech to check yours.
Two ways to run a sump
One kills and gets consumed doing it. The other just refuses to let anything breed.
Your redose window. A biocide depletes as it kills, so once it drops below the effective level you have hours before the bloom catches up. Mark II declines and recovers by attrition, on a scale of days.
Typical dosing cadence. Biocides usually go in continuously, daily or weekly. Mark II, if it is needed at all, goes in monthly or bimonthly.
Mark II is effective against both bacteria and fungi in the same dose. A biocide program controlling both usually needs a bactericide and a fungicide mixed together, which is two products, two schedules and two safety data sheets to manage instead of one.
Plotted over a year
A sawtooth against a sine wave you can plan around.
Chart the microbial population of a sump on a biocide program and you get a sawtooth: a climb, a steep cut when the dose lands, then a bloom back up before the next dose. Chart the same sump on Mark II and you get a shallow, protracted sine wave with no extremes at either end. That absence of extremes is the whole reason fluid life can extend indefinitely instead of getting scheduled for replacement.
When a sump is already gone
Some sumps need the kill first and the hold second.
A sump that has already gone sideways, with uncontrolled growth and years of neglect behind it, is not a job for Mark II alone. Combined with a Triazine-type biocide, you get the shock speed of a biocide kill on day one and the persistence of Mark II from day two onward, instead of choosing between a fast fix and a lasting one.
Many fluid manufacturers already build Mark II into their own formulations, which means a good number of shops are running it today without a tankside addition of any kind. If you are not sure whether your coolant already carries it, that is a phone call, not a guess.
Most shops running Mark II run it as one piece of a larger routine rather than on its own. See the full Zero Waste program it usually sits inside.