As nutrients are extinguished the bloom can die out quickly, as fast as a weekend. As the FA flourishes on the bottom it can quickly absorb enough nutrients to starve a 'weak' bloom. When the bloom is at around 5' the conditions are marginal or low concentration and more vulnerable to a depletion. If carbonates (alkalinity) are low the bloom will decrease due to not enough carbon (CO2-CO3) despite an adequate nitrogen phosphourus concentration. Very soft water can require what appears to be very large amounts of lime every 2-3 yrs to maintain higher alkalinity.


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