So this got me wondering if I could come up with a decision matrix for determining testing frequency. Slow Saturday here. I'll probably describe this more in my build thread, but here's something I came up with to help determine each persons test frequency based on their tolerance for risk, test equipment, design, etc.
Now if I can just figure out how to post a spreadsheet (probably need to do a dropbox for this).
I added my "Actual" last after figuring out the individual ratings. Found it interesting this held up more or less to my actual, with the exception of pH - normally that would be weekly for me but since I have Apex I monitor it continuously. I also don't monitor Alk quite as frequently as bi-weekly (meaning twice a week).
I will also increase frequency based on changing dosing or adding livestock/food which I suppose would be changing "normal variance".
Anyhow, I thought it an interesting exercise.
| Impact | Normal Variance | Indicator | Potential Failure | Ease of Test | Sum of Ratings | Frequency Recommended | Actual Frequency |
Properties | | | | | | | | |
Temp | 3 | 1 | 3 | 3 | 3 | 13 | Daily or Continuously | Continuously |
pH | 2 | 2 | 2 | 1 | 3 | 10 | Bi-Weekly | Continuously |
ORP | 2 | 3 | 3 | 2 | 3 | 13 | Daily or Continuously | Continuously |
Salinity | 3 | 1 | 1 | 2 | 2 | 9 | Weekly | Weekly |
Nutrients | | | | | | | | |
NO3 | 2 | 2 | 1 | 2 | 1 | 8 | Weekly | Weekly |
PO4 | 2 | 2 | 1 | 2 | 1 | 8 | Weekly | Weekly |
Minerals | | | | | | | | |
Alk | 2 | 1 | 3 | 2 | 2 | 10 | Bi-Weekly | Bi-Weekly |
Ca | 1 | 1 | 2 | 2 | 1 | 7 | Weekly | Weekly |
Mg | 1 | 1 | 1 | 1 | 1 | 5 | Monthly | Monthly |
| | | | | | | | |
Rating Definition | Impact | Normal Variance | Indicator | Potential Failure | Ease of Test | | Total Rating and Corresponding Test Frequency Recommendation | |
3 | Negative and severe impact in hours | Highly variable in <24 hours with control | Indicates imminent loss of livestock | High risk of failure of direct control | Automatic Testing | | 12 | Daily or Continuously |
2 | Moderate impact over days | Moderate fluctuation with normal usage or build up rate | Indicates potential loss of livestock | Moderate risk or control or indirect response failure | Instrument; Simple test; <2 minute result | | 10 | Bi-Weekly |
1 | Little to no noticeable impact over days | Low usage or build up rate | Indicates less than optimum health | Low risk of control or indirect response failure | No Instrument;Complex test; >2 minute result | | 7 | Weekly |