You don't measure tannins. The darker they stain your water the more tannins are in the water. Tannins help to soften water and if enough is present can lower PH. They are actually good for fish and the tannins have anti-bacterial and anti-fungal properties.
One week ago I suggested this in an offline conversation in a bid to help this lady with all of her tank concerns, I chose to go offline with you Janice as I didn't wish to offend anyone, I ran it by aqua-Chem who could only summise that to low a temperature was a bad thing, my suggestion wasn't to go below that required for the fish, you said pH control was out of the hands of a beginner?
Ammonia Toxicity and pH Changes
The effect of pH variation, within the range 6.5, 7.0, 7.5, 8.5 and 9, on activated sludge denitrification of a synthetic wastewater containing 2700 mg/l NO3-N was examined using bench-scale Sequencing Batch Reactors. Two major effects were observed. One, at pH values of 6.5 and 7.0, denitrification of a synthetic wastewater containing high nitrate levels was significantly inhibited. Two, denitrification was achieved at higher pH values of 7.5, 8.5 and 9.0, but the accumulation of nitrite increased significantly as mixed liquor pH increased with peak values of 250, 500 and 900 mg/l NO2-N, respectively. As the pH rose, the specific rate of nitrate reduction increased. At the same time the specific rate of nitrite reduction increased in the absence of nitrate. In the presence of nitrate the specific rate of nitrite reduction remained constant, and the degree to which nitrite reduction increased in the absence of nitrate was a function of increasing pH. While increasing pH from 7.5 to 9.0 affected nitrite intermediate accumulation, the overall time for complete denitrification (reduction of both NO−3 and NO−2) was similar for the pH values of 7.5, 8.5 and 9.
You must understand the paper in the link above,
So by reducing T' it is possible to control free ammonia NH-3, nitrite accumulates significantly with increased pH. High pH reduces nitrite providing nitrate is 0. A mild pH reduction while I agree with your point, perhaps not for beginners, it is perfectly possible to achieve the goal without too much concern for the fish. The water change will reduce both NO-2 and NO-3 while keeping ammonia in its free form at a much safer level. 7.5 pH should be the eventual goal at a reduced T' with regular small water changes to control nitrite and nitrate until such time that the system becomes cycled.
What has changed so significantly in 7 days that couldn't be addressed then?
I still mean to cause no offence but I can't help feeling this could have been resolved much earlier?
