Monitoring in mature systems

[Kobus Jooste]

I have been looking at a lot of input and my own experience.  If a system is designed and managed correctly, what should we monitor in the end?  Are performance issues not typically design flaws or operational decicions rather than ecological processes?

 

The concensus from what I could read is pH, DO and Ammonia (I am assuming we all watch temperature naturally) is all we need to think about.  Thoughts?

[TCLynx]

I do regular tests with the test kit but yea mostly I monitor pH.  DO I rarely check since the test kit I have is really tedious, no meter, but my fish tend to tell me when the DO is getting low (long before it reaches dangerous levels for them) by going off their feed.  Only danger there is when one is away and DO drops and you are not around to notice and take corrective action.

 

Anyway, pH is the only one I strongly recommend people do a few time a week, otherwise I usually only check the others every couple weeks or if something tweeks me as being "off"

 

Of course when changing fish loads or adjusting feeding, testing for ammonia and nitrite more often is recommended.

[Gina Cavaliero]

We only test once every couple weeks now in our commerical system and really that is more of just a formality.  We check DO, pH, ammonia and for nitrates and nitrites, just to see what they are doing.  Our small system rarely gets tested.  If you are interacting with the system daily, it is interesting how just normal observation will indicate that something might be off.

[TCLynx]

Gina, How are you adjusting or buffering pH?

 

I find that in my tower system (that is fed on rain water now) I seem to need to keep a closer eye on the pH since it can go from 6.8 to down below 6 in less than a week when it runs out of carbonates.

 

My other systems so far don't need such careful monitoring because one is completely full of shells and topped up with well water and the other one is currently still on well water which usually keeps the pH above 7.6 if it hasn't been raining a lot.

[Kobus Jooste]

Gina - that sounds like a very stable system you operate.  I'm impressed.  I always considered commercial operators as folk who need to keep a much closer eye on their set-up.  Would you consider an aquaculture style monitoring, logging and warning system a complete waste of time then? (pretend you can get one for free)

[Gina Cavaliero]

It is incredibly stable.  The only variations we have really seen have been a result of substantial fish mass growth which definitely affected DO and ammonia.  I think the minimal amounts of variable input, ie, little to no rain water helps it to maintain.

 

I wouldn't say that an aquaculture style monitoring, logging and warning system would be a waste of time Kobus.  It would possibly impart something on a more intimate level than I am currently seeing.  We did monitor more frequently in the beginning and the more the system stabilized, the less we needed to test as often.  

 

For pH, we only ever have to buffer up.  Again, as we have very little rain water being introduced to the system to affect pH, only the amount of well water we add once every 10-12 days will tend to lower it a little bit.  Without testing, we already know to add a bit of calcium carbonate every two weeks to bring the pH back up a little after the introduction of our 6.2 well water. 

[Jay Wolf]

Gina hit it on the head with checking DO, pH, ammonia, nitrates and nitrites.  Those were the best indicators when I was raising fish.  Is there anything else you should be checking for plant wise?  Or are those tests good enough?  I guess I don't know...........

[Kobus Jooste]

If a system is stable, then you could infer nitrates and nitrites from the ammonia reading.  Many people thus suggest only watching temp, do, pH and ammonia.

Jay Wolf said:

Gina hit it on the head with checking DO, pH, ammonia, nitrates and nitrites.  Those were the best indicators when I was raising fish.  Is there anything else you should be checking for plant wise?  Or are those tests good enough?  I guess I don't know...........

[TCLynx]

Your well water pH is 6.2 Gina!!!!!!  What!!!!!  I didn't think there was much of anywhere here in FL with water that wasn't out of the limestone.  How deep is the well?  I'm jealous.

 

Yep I would say the temp, do, pH an ammonia are the ones to monitor more constantly in a system that needs that kind of careful monitoring.  And in a backyard set up (depending on source water and media buffering, some systems don't need that close of pH monitoring while others might want to be tested every other day) pH is probably the only one I would monitor all that closely figuring the temp is mainly of interest at the extremes of the seasons and DO is too much trouble for the average hobbyist.

[Jay Wolf]

Thanks Kobus!  Good to know that I am there already!!! 

Kobus Jooste said:

If a system is stable, then you could infer nitrates and nitrites from the ammonia reading.  Many people thus suggest only watching temp, do, pH and ammonia.

Jay Wolf said:

Gina hit it on the head with checking DO, pH, ammonia, nitrates and nitrites.  Those were the best indicators when I was raising fish.  Is there anything else you should be checking for plant wise?  Or are those tests good enough?  I guess I don't know...........

[Gina Cavaliero]

Yep, 6.2.  It is a 221' deep well.  But remember, we are in the 'mountains' of Florida!  ;)  That probably has something to do with it.

TCLynx said:

Your well water pH is 6.2 Gina!!!!!!  What!!!!!  I didn't think there was much of anywhere here in FL with water that wasn't out of the limestone.  How deep is the well?  I'm jealous.

 

Yep I would say the temp, do, pH an ammonia are the ones to monitor more constantly in a system that needs that kind of careful monitoring.  And in a backyard set up (depending on source water and media buffering, some systems don't need that close of pH monitoring while others might want to be tested every other day) pH is probably the only one I would monitor all that closely figuring the temp is mainly of interest at the extremes of the seasons and DO is too much trouble for the average hobbyist.

[TCLynx]

221' deep, well that is a deep well, for FL.

[Terri Mikkola]

First, let me say, I'm not a commercial grower and what I offer is strickly my opinion based on water quality testing as it relates to wastewater treatment. What I've learned is that the most stable system can take a turn for the worse even though visual indicators are ok. By combining visual inspections with daily tests ,one can be assured their system is working as it should be. To take it a step further, I would develop a process control plan using a spreadsheet to log your daily results and observations. I would add trend charts for each parameter based on 7 day averages to determine if your system is stable or moving in a direction that requires some type of action. A process control plan can assist with troubleshooting and determining the proper course of action to take.

 

TC mentioned on another topic thread how stocking densities impact water quality and stability. It's a great point. Low stocking densities create a more stable and forgiving system, which, I assume, is why some commercial growers don't feel the need to test daily. I would hate to see a business suffer a major loss due to water quality issues that could have been averted (my opinion).

 

And as for the the minimum parameters to test for - pH; temp; TAN (including determining NH3 toxicity levels); nitrate, dissolved oxygen, and alkalinity.

I would also send samples out to a lab to test for total coliform / e coli for food safety.

 

For high stocking density systems, I would add to the above list, TSS, BOD, and CO2, which can be calculate with pH and alkalinity.