For BGA (cyano) to appear, it means that your params are out of whack.
BGA is capable of getting a stronghold in your tank when the nitrates and/or phosphates are out of "optimal" conditions.
There is a formula called the REDFIELD RATIO (RR). It is used to help prevent cyano outbreaks from starting. Here is how it works (whether for SW or FW set-ups)
(NITRATE/PHOSPHATE)x0.7= RR
The perfect RR (again for SW or FW) is 16.
Example:NO3and PO4 measured in mg/l
NO3/PO4* 0.7= Redfield Ratio
(10/.25)*0.7=28 With this RR you would have a significant outbreak of cyano.
SO what do you do...well...lets play with the numbers...
If we increase our NO3, the results are
(20/.25)*0.7=56 So we are going the wrong way with the RR.
What if we increase our PO4?
(10/.50)*0.7=14 Much better...but still not an RR of 16...plus its alot of PO4!
You can see that a small change in one param or another can have a huge impact. What you need to do is measure your 2 key params, then figure out which one is easiest, and safest, to adjust.
Keeping an RR of 16 will cause the cyano to slowly start dying away. Manually try to remove as much as possible. A huge mass of dying cyano can and will spike your params.
Hope this helps
