Which parameters do you think need to be or are worth being constantly measured?

[jta117]

Ive posted here before and Im sorry if im taking too much of your time guys but youve been really helpful. Brief background behind the question is that my bachelor thesis is about designing a smart aquarium.

**Some more elaboration on the question:**
It doesnt really make sense to have 20 different sensors constantly measuring different parameters inside the aquarium so im trying to limit that to the most essential parameters that might be related to the other parameters.

So far its been a bit difficult finding a mathematical relationship between the parameters, so if someone knows some good sources that could provide some more information about this, it would be really helpful, since I would then just have to measure 5-6 parameters in the aquarium and the software would just basically calculate/estimate the rest of the parameters with tolerances for accuracy of course. If after 2 days of googling around, I couldnt find such relationships, does it mean they dont exist?

To make answering the question a bit more easier; think of it this way; what would be the parameters that you need to regulate so that everything stays healthy and alive?



**Some more information:**
These are the parameters that are considered critical parameters and ive also listed them according to their relationship with each other (the ones ive found so far, so if you know of another one please let me know):

1. Calcium, Alkalinity, Magnesium and pH
2. Salinity and Temperature
3. Ammonia, Nitrite and Nitrate (Nitrogen Cycle)
4. Phosphate (I havent found too much info on this but it seems that its dependent on pH and Calcium)

 

[watchguy123]

Salinity should be stable and probably easiest to keep that way. Mix salinity to desired level for water changes or initial set up. Use ato to replace evaporated water. Although a doser particularly in a small tank can cause salinity to rise.

temp stability requires decent heater to warm and fan or chiller to cool. Need a decent thermometer/controller to regulate

alkalinity in a reef tank requires either a calcium reactor or automatic dosing. Both require testing to dial in. Calcium follows alkalinity. If alkalinity is stable then calcium should be as well as a general rule. Magnesium addition can be via media in calcium reactor or on dosing pump but magnesium doesn’t vary much over time once dialed in.

pH is more challenging to purposefully effect except by adding fresh air or using co2 scrubber. So although cool to track, challenging to manage.

nitrite and ammonia should all but be absent from cycled stable tank. In a cycled stable tank, I’m not sure whatever variations in levels exist are meaningful.

Nitrate and phosphates are controlled by food import vs nutrient export. So over feeding always has potential to shoot up nutrients. Nitrates seem to be aggressively consumed by lots of critters so can be managed somewhat by live rock (bacteria hangout), ceramic small pore media like Siporax, macro algae in a refugium, protein skimmer, socks amd water changes. Phosphates easily rise in a reef tank and sometimes require extra effort to remove like GFO or lanthanum chloride.

the higher level of nutrients, the more intense light seems to be tolerated. The lower level of nitrates, the alkalinity needs to be lower.

water movement/flow also plays a role but no one seems to have quantified it.

not sure I answered your question

 

[taricha]

So you want a "smart aquarium" that will turn things on and off based on measurements in order to keep things stable and corals happy.

Here's my thoughts on it - From simple to complex.

Flow: Powerheads on 24/7. Done.

Aeration: Skimmer on 24/7, plumb the skimmer cup to a drain. Done. This will help stabilize O2, and (more slowly) CO2 which, if extreme, can have implications for pH.

Light: Run strong ones on a timer. To get fancier, reverse light a refugium during the dark of the main tank. This will stabilize O2, and somewhat stabilize pH.

Salinity: measure conductivity and use it to control top-off water for evaporation

Alkalinity: it is possible to automate this measurement, but not simple (see KH guardian), or you can set up your own auto titration/pH system. It's worth it though, because measuring Alk consumption you can control the dosing of Alk but also Ca and Mg, since these are taken up in very reliable ratios to the alkalinity. You can dose 2 or 3 part solutions to handle these. Alk changes fast enough, that more stability could be achieved if it was measured more than daily.

pH: done. you took care of it with aeration, light, and alk. (if you wanted to get super fancy, you can switch between multiple higher or lower pH sources of Alk to further control the pH, but that's not necessary).

Food / Nutrients:
Easy - measured amounts of fish food on timed auto feeder.
More complex, more automated - measure NO3 and PO4 and switch between food sources with different N/P ratios.
Also - could dose organic carbon (ethanol, vinegar etc) tied to results of daily NO3 and PO4 tests.
Oh, can't automate either of these tests (unless you have infinite budget for UV NO3 sensor (google scholar))

That should keep the tank stable on a time scale of months . Minor/trace elements will get out of whack without water changes over a longer time period.

(except that in addition to needing to test NO3/PO4 manually, somebody has to harvest the algae out of your fuge on a weekly basis.)

Alternately if you want to cheat - or the project gets too hard, you can just change 10% of water daily with a reef salt mix and need to measure almost nothing.

 

[NeonRabbit221B]

Randy Holmes-Farley has some fantastic articles that go in depth on the different parameters and interactions. Most you can quickly find by searching his name followed by parameter. I would say that if I could continuously measure a single parameter it would be alkalinity as in a younger tank that seems to bounce quite a bit with the increase in growth. Phosphates would be fantastic to me but haven't found anything for continuous measurement.

 

[runjmb]

You are over thinking the hobby. Just need to maintain stable Alk and Calcium, nitrate and phosphate. Everything else is secondary. Water changes weekly and you're done.

I use a KH Guardian.

For what it's worth ive got a tank with high end acro only.