I have two juvenile discus who need to be quarantined for treatment. I thought they were goners (acting blind, not eating) but they've started eating again. I have them in a large breeding holder that hangs outside of my main tank and water from the main tank is pumped into the breeder. I had a couple ghost shrimp and an albino BN pleco that right now are being acclimated to the main tank. I'm turning the 20 gal into a barebottom quarantine tank. I'm taking out the gravel but my question is can I replace all the water with pure RO water or will I ruin the beneficial bacteria in the filter? The tank has to be spotless... please help!