Day 24 RET summer training

Day 24

We came back from the weekend to find DEAD Fish! NOOOOO! We left all systems running over the weekend, this includes controls. During our 24 hr data collection the prior week we saw that pH levels drop for several hours during the day but we did not have enough data to see what time they come back up. In any case, we expected pH dispenser control to do it's job. Problem- the processing time of 8 seconds is too short of a window for conditions to stabilize. pH dispensed needs more time to mix with water. The 8 second response kept the dispenser "dispensing" eventually draining the reservoir dry. About 1/2 of solution bottle was dispensed and as a consequence killed several of our fish. It is difficult to assure that no harm will happen to life when experimenting and creating systems that are currently not in place. We did not expect this loss and thought our plan was solid. We will try deploying either today or tomorrow and will make sure to remove all fish. On the other hand, we had an inch growth in our plants over the weekend. We will continue measuring growth for the next few days but it would be interesting to see if we had more growth with high pH than normal pH levels (7.1-7.5) these next few days. We will see.

Not good:(

We have our final data collection (not really, we were just told DO graph shows to many variable points, not a good thing when dealing with a control system that needs to conserve battery life--basically we'll have to set this control to take less data readings), see below:

Above. Temperature shows varying points but this is expected with the sensitivity of these sensors. Vardhman will work on an algorithm to remove these points.

Above. We will replace this graph tomorrow but for now black points shows control activated, DO levels rise shortly after; you see a pattern of low levels, black point, then a rise.

Above. Self explanatory (from left to right)-- DO sensor was dependent on temperature and DO limit was 7.5 (if DO falls below 7.5 control activated). Vardhman changed this to so that the limit for DO was 8.

Above. DATA.

A little under 2 days of data.

Above. pH levels maintained with control activated (top line):)

Above. This DO graph will most likely be replaced tomorrow.

Tomorrow's goal will be to add disturbances to an isolated volume of water, observe and record this data.