Post 2 of 2 today...
From my research to date, it appears that risk of aggressive dosing is largely two - fold.
First if the bacteria colony is grown to fast, the "bloom" can rapidly deplete the oxygen, resulting in pH and alkalinity falling and potentially crashing the tank. Let alone the harm the can be done to the fish and corals from instability in the tank parameters.
Second, if the bacteria colony is not reduced to a reasonable size by the time the nitrates and phosphates reach the desired level, the bacteria can continue on a run away and totally eliminate all the nitrates and phosphates (this is my interpretation of reading between the lines but not specifically stated) which also has a negative effect on the tank. Articles are less forward in discussing this effect, they only state that it leads to problems with tank parameters.
My tank carries some additional risk on the second item as it has had sustained high levels of nitrates for a long time, which leads to saturation of the rock and sandbed. As the bacteria consumes the nitrate in the tank, more is released from the rocks and sand. It is possible that I could build an oversized bacteria colony, and when the saturated nitrate runs out, I could end up taking my nutrient levels down to far. Or end up with problems with tank parameters, that they are somewhat elusive on.
Based on my experience last time I was carbon dosing, I still want to take a more aggressive stance, but have more understanding of the risks. So I am on course for the following plan, increase Vodka dosing by 1.2ml per week for the first 12 weeks, then reduce to 0.5 ml increases per week.
Once I see a 50% reduction in nitrates, I will reduce the dosing by 25% and then maintain consistent dosing. I can monitor to determine if the nitrates are still falling or if need be slowly increase the dosing to begin the nitrate falling if need be.
At each 1/4 point from my initial 250ppm, I will reduce the dosing by 25% to try and scale the dosing down and not over shoot on the bottom end.
There are a few things that are on my radar for consideration, the first is that my UV sterilizer may inhibit bacteria growth, I will be shutting it down for the time being. It may even be an asset to slow down the bacteria colony on the bottom end.
The other item is to increase the oxygen saturation, I have some old skimmers around that I could put on the tank. I dont think I want to set-up ozone at this point, which is the other option to increase oxygen saturation.
I still expect this will take more than 6 months to get any substantial results, With the amount of saturated nitrate in my rock and sand. Once I achieve 125 ppm, I will increase the water change frequency to help add stability.
Cheers
Bill
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