I have a theory about dosing bacteria:
I've noticed that when I dose bacteria according to the tank size that I have, bad things seem to happen. Mainly, I've noticed STN on some corals. And, like clock-work, when I skip a couple of doses, the STN stops. I keep taking the dosage back a little and try to slowly work back to where it 'should' be, according to the manufacturer's instruction. But, in the end, I see negative results when I get to a certain point.
Here's what I know about the idea behind bacteria dosing, or at least what I think I know. Basically, we're talking about my personal speculations. Your tank has a pretty static amount of surface area, unless you're constantly changing things. But, if you're leaving your tank alone, your available surface area doesn't change much. Bacteria multiplies, clings to the surface area in the tank, and calls that home. In my mind, there has to be a point where bacteria has saturated an area. If we accept this idea, then eventually the total surface area of our tank will become saturated with bacteria, and the left over bacteria will end up in the water column. In turn, this excess bacteria is supposed to be removed via skimming and/or water changes. It's at this point that we may need to add more carbon source, in order to grow our population even more. This is where the balancing act begins.
If we add too little carbon source and bacteria, the system is ineffective at achieving those Ultra Low Nutrient System levels that we so very much desire. But, on the flip side, dose too much, and you'll strip your system of nitrogen and phosphorous too much and/or too quickly. Now, I've heard that in order to sustain life and new growth, our systems need a small amount of N and P. That being said, it's reasonable to assume that each system has a specific level of Required N & P. If we dose too much bacteria and carbon source, we can actually cause the levels, even if only for a short time, to dip below the Required N & P. It is at this point that we start seeing the negative impact of dosing too much. Bottom line: Dosing bacteria can be dangerous. It's POWERFUL!
So, now we've identified the risk involved with a bacteria dosing driven system. How do you know where the Safe Zone is? What's too much, and what's too little?
To answer this, we turn to our bacteria's manufacturer's label/instructions for dosing limits. It never fails; the dosage is almost always dependent upon how many gallons your system has. Here's the problem with that: No two systems of equal volume are the same.
The bio-loads and surface area are always different. John might have a 60g reef that produces an amount of N & P that requires a dosage within the manufacturer's recommended range. But, my 60g reef doesn't. It has a little more live stock than what I would typically put in a 15-20g nano. Furthermore, my tank doesn't have the amount of surface area that many other tanks do, of the same size. It's a bare bottom with around 20 pounds of live rock. That being said, if I dose the 'normal' amount, it results in cloudy water from a bacteria bloom. That seems to annoy the animals in the tank, to the point of tissue necrosis in some corals. This is why following the labels and instructions without caution can result in negative results. Should the manufacturer change their instructions to explain that each tank is different? Sure, but when does it stop? You can't explain every situation on the back of a bottle.
I've heard/read this before, and to be honest, I didn't put much stock in it: Start small, and slowly ramp up your dosage. I figured if it was on the label, then it was ok, and maybe with some things that's true. But, with bacteria, I've learned that you have to start off slowly to minimize the risk, and the risk is kind of high.
That being said, I'm making some changes with how I handle this tank, but it's going to be slow. My biggest flaw is I jump into things without thinking and taking my time.
Here's what's happening:
As mentioned before, I'm adding 30 pounds for dry rock and 40 pounds of dry sand. I'm not sure how much of the rock will reside in the DT, but like mentioned before, it should be interesting and look nice. The other thing I'm doing is taking it easy on the dosing for a long while. Things need to settle. After that I'll start the bacteria, SLOWLY. I should have a bit of a buffer with the extra rock and sand. Time will tell.