200 GALLON JUNGLE STYLE

Paul G

Active member
Today's numbers

NO3: 0
PO4: 0.17 ppm
K: 20 ppm
dKH: 5.66
dGH: 3.70
Ca: 16.80 ppm
Mg: 5.85 ppm

Potassium now showing at the expected reduced concentration with alkalinity unchanged. Dosing of K2CO3 to be increased 50%. ODE = 4.5 L, GH now inclining slightly so I'm leaving the ODE there.
 

Paul G

Active member
CONCLUSIONS DRAWN FROM THE SWCR EXPERIMENT

After several days of testing zero NO3, but normal PO4, I have a concern about nitrogen insufficiency. Certainly DIN is being continuously evolved, but between more sparing feeding and increase in SWCR rate, there is no surplus water column NO3. To the extent that nitrogen is bioavailable from all sources, the plants are consuming it. Last night and again this morning, 15 mL KNO3 w/urea (SeaChem Nitrogen), was added. In the newly accelerated SWCR, a dose will be calibrated to assure non-zero NO3. Something learned in the past few months of trials in this water change scheme is that maintaining non-zero nitrate derived solely from fish food can result in DOM levels that are difficult to manage, even with liberal application of chemical filtration media. Though attractive is the idea of gaining growth factor nutrition from natural outfall of environmental metabolism, it does not work so well in what is essentially a closed system due to unavoidable concomitant generation of dissolved organics. This accentuates the superiority of water change over chemical filtration for pollution control in closed systems. It is preferable to resort to pure supplementary NO3 in correctly calibrated dosage and to double down on all DOM reducing strategies, in particular water changes. It is a mistake to infer low DOM from low DIN and low orthophosphate. True oligotrophy is defined by diminished figures for all three of these parameters. The problem arises from the relative difficulty in reliably measuring DOM. Redox potential should be a fairly good indicator, but my data shows that there is more to it. I am convinced that DOM is a primary growth factor in algae population. Incipient nuisance algae is an indicator of high DOM, and the relationship of this condition to ORP is not so straightforward as I had expected. A highly oxidizing environment certainly will derive from persistent high oxygen tension, but this does not necessarily ensure that DOM is not also present in larger than expected concentrations. I have been puzzling over the gradual eutrophication of this system while seeing very high ORP and very low DIN. Overfeeding will eventually manifest and cannot - cannot - be corrected with activated carbon, regardless of the charge weight.

The SWCR does work, and is best at high change rates. As long as various means of supplementation are implemented to provide stable background chemistry and sufficient plant nutrient, the faster the turnover the more efficiently does the system shed DOM. The Hardness Reconstitution Reactor (HRR) and K2CO3/MgSO4 dosing can be adjusted with relative ease to attain K+, Ca++, Mg++, and CO3-- at appropriate concentrations. This strategy for maintaining a planted tank indefinitely through automated techniques is highly promising. Just now it looks like fish food provided sanely will support non-zero orthophosphate within oligotrophy. Supplementing with KNO3 to satisfy nitrogen requirement is a simple matter.

Today's numbers

NO3: 0.89 ppm
PO4: 0.12 ppm
K: 15 ppm
dKH: 5.60
dGH: 3.59
Ca: 17.6 ppm
Mg: 4.88 ppm

Potassium and alkalinity falling behind the SWCR. I am increasing K2CO3 to 120 seconds per dose, 20 mL three times per day (= 60 mL daily total).
Magnesium also a bit short. I am increasing MgSO4 to 120 seconds per dose, 20 mL twice a day (= 40 mL daily total).
I am restarting KNO3 w/urea (SeaChem Nitrogen) at 5 mL (30 seconds) once daily.
All subject to revision as the situation develops.

Pretty clearly, the increased SWCR rate is effectively diluting the water column. The reduction in DOM is having an immediate impact. Confidence is high that the lighting can be increased, as is the plan, without occasioning onset of excessive algal growth. It has taken just a couple of days for this to prove out, as much of the scuzzy periphyton has spontaneously abated, as has the stubborn recurring oil slick.

Consideration of effects to micronutrient/trace is due. At present I am not compelled to increase doses here because I have no data, but this will not be neglected.
 

Paul G

Active member
Today's numbers

pH: 6.64
NO3: 1.33 ppm
PO4: 0.11 ppm
K: 20 ppm
dKH: 5.94
dGH: 4.03
Ca: 16.8 ppm
Mg: 7.32 ppm
 

Paul G

Active member
Today's numbers

pH: 6.65
ORP: 323 mV
NO3: 1.55 ppm
PO4: 0.26 ppm
Fe: 0.29 ppm (@ 08:00)
K: 30 ppm
dKH: 6.33
dGH: 3.70
Ca: 17.6 ppm
Mg: 5.37 ppm

This AM I added 20 mL Brightwell FW Razor and 100 mL Dr Tim's Re-Fresh. Also added a third daily 20 mL dosage of MgSO4 solution at 17:00. Alkalinity and potassium coming back into line. HRR and SWCR are balancing on a desirable calcium number.
 

Paul G

Active member
Today's numbers

pH: 6.68
ORP: 336 mV
NO3: 1.77 ppm
PO4: 0.30 ppm
Fe: 0.19 ppm (@ 07:48)
K: 30 ppm
dKH: 6.78
dGH: 4.48
Ca: 18.40 ppm
Mg: 8.30 ppm
Ca/Mg: 2.2/1
TDS: 290 ppm
DO: 8.2 ppm
CO2: 40 ppm

Data suggests that no alteration in dosing rates of Flourish Comprehensive or Flourish Trace are needed to answer to the accelerated SWCR. An appreciable level of Fe is testable within two hours of the first daily dosing event. I plan no change in the Excel or Advance dosing either.

As usual, numbers stated for those parameters that normally fluctuate throughout the diurnal cycle are total daily running averages (TDRA). The background chemistry just now is ideal, and nutrient level is oligotrophic. I suspect, watching numbers rise as they have over the last few days, that a small additional water change may be in order just to define an upper limit to the tendency toward "creep". Will the small water change attendant to a filter change event be about the right amount? Today is 17 days since the filters were last serviced. Thursday next would mark the 3 week filter change interval, but I am doing it today.

LOOP1L velocity 145 gph
Stage 1: 100 micron mechanical, no core medium
Stage 2: 20 micron mechanical, 800 grams Renew w/ 250 grams Purigen

LOOP1R velocity 112 gph
Stage 1: 100 micron mechanical, 250 mL Purigen*
Stage 2: 20 micron mechanical, HRR core**

LOOP2 velocity 320 gph
Stage 1: 100 micron mechanical, no core medium
Stage 2: empty

LOOP3 velocity 223 gph
Stage 1: 100 micron mechanical, no core medium
Stage 2: empty

*Purigen charge from previous filter change, rinsed and returned. Based on lightness of color, this appears not to be exhausted.

**The Reef Reactor (HRR) should be removed and rinsed thoroughly. It is a porous medium and will support biofilms. Unclear that colonization interferes with dissolution of material, but in any case I don't need the HRR to become a bio-filter.

All 100 micron filter cartridges were dirty enough to justify replacement at two weeks. Opening these filters results in a water change of about 5 gallons. I also moved nearly 3 gallons to the Q tank to top it up. I will regard this as an 8 gallon "big gulp" water change for practical purposes.

The MD55RLT pumps have been running 24/7 for over ten years now. Pump #3 is showing its age. Dealing with this may occasion a total redesign of the circulation system with some simplifications I have been thinking about.
 

Paul G

Active member
Today's numbers

NO3: 0.88 ppm
PO4: 0.54 ppm
Fe: 0.25 ppm (@ 09:28)
K: 35 ppm
dKH: 6.67
dGH: 4.03
Ca: 17.6 ppm
Mg: 6.83 ppm
Ca/Mg: 2.6/1
TDS: 300 ppm

Hardness numbers are down a bit as expected after yesterday's 8 gallon water change. If the HRR is outrunning the SWCR, how fast these numbers rise will determine the next ODE timer increase.
 

Paul G

Active member
Today's numbers

pH: 6.69
ORP: 398 mV
NO3: - n/t -
PO4: 0.19 ppm
Fe: 0.09 ppm (@ 09:49)
K: 35 ppm
dKH: 6.44
dGH: 4.15
Ca: 20.00 ppm
Mg: 5.85 ppm
Ca/Mg: 3.4/1
TDS: 310 ppm

Calcium is building back quickly. Before experimenting further with the ODE timer, I am throttling LOOP1R (HRR throughput velocity).
 

Paul G

Active member
Today's numbers

pH: 6.70
ORP: 443 mV
NO3: 0.20 ppm
PO4: 0.14 ppm
Fe: - n/t -
K: 30 ppm
dKH: 6.50
dGH: 4.03
Ca: 17.6 ppm
Mg: 6.83 ppm
Ca/Mg: 2.6:1
TDS: 290 ppm

Throttling flow in any circulation loop is definitely not the way to get this done. More depends on the flow rate than the HRR ion output - in particular the CO2 dissolution from the diffuser in that loop. The chiller being in LOOP1R slows it considerably more than LOOP1L due to its fairly large insertion resistance (head loss). I chose LOOP1R for the HRR for that reason because I suspected the flow rate for ion pickup would likely overrun the SWCR. It's the slowest loop in the system, but still too fast. I had reduced LOOP1R velocity to 85 gph, just to see if that was a viable shortcut to a solution.This more or less immediately initiated pH left:right differentials and destabilized tank CO2. Moving the pH controller from the pH-R monitor to the pH-L monitor fixed that, but I had to turn the velocity back up to max which is currently 115 gph. So the alternative now is to increase the ODE time as originally proposed and take advantage of the higher water change rate.

I will begin with increasing from 4.5 L to 5.0 L per event which increases the ODE from 120 seconds to 133 seconds. This bumps up the daily source-water demand to 120 liters, or 31.7 gal/day.

For anyone interested in how Apex does this, here is the program in four screen shots.

 

Paul G

Active member
Today's numbers

pH: 6.7
ORP: 454 mV
NO3: 0.05 ppm
PO4: 0.17 ppm
Fe: 0.22 ppm (@ 07:37)
K: 35 ppm
dKH: 6.83
dGH: 3.81
Ca: 15.20 ppm
Mg: 7.32 ppm
Ca/Mg: 2.1/1
TDS: 290 ppm
 

Paul G

Active member
Today's numbers

pH: 6.7
ORP: 458 mV
NO3: - n/t -
PO4: 0.21 ppm
Fe: 0.10 ppm (@ 06:59)
K: 40 ppm
dKH: 6.95
dGH: 3.81
Ca: 16.00 ppm
Mg: 6.83 ppm
Ca/Mg: 2.3/1
TDS: 290 ppm
 

Paul G

Active member
Today's numbers

pH: 6.72
ORP: 472 mV
NO3: 0.01 ppm
PO4: 0.24 ppm
Fe: 0
K: 40 ppm
dKH: 6.95
dGH: 3.58
Ca: 16.00 ppm
Mg: 5.85 ppm
Ca/Mg: 2.7/1
TDS: 280 ppm

SWCR and HRR are balancing.
If the ODE is increased to 150 seconds, the drain volume is 5.6 liters. The RO/DI demand increases to 134.4 liters or 35.5 gallons daily. I am making this change now.
I am fortifying the Flourish dose with additional ferrous gluconate. For a start, 200 mL will be added to the vat and the Flourish topped off.

FURTHER CONCLUSIONS CONCERNING SWCR

Since the SWCR has been accelerated the redox has finally ascended to its normal high. DOM is now well-controlled and the clarity and crispness of the system is much improved. No amount of chemical filtration gives results as clearly effective as water changes. In terms of operational costs, chemical filtration is extremely expensive, while RO/DI is relatively cheap. Chemical filtration is labor intensive inasmuch as it involves additional steps in the filter change procedure. Water changes are a breeze if automated - no hoses, no buckets, no spills - and, if parceled over time as in the SWCR, no instabilities. Since increasing the ODEs to 24 daily and then the ODE time, the results have been salutary. The importance of keeping organic waste at trace levels cannot be sufficiently stressed. This promotes optimal health of plants and animals and is of primary importance in algae control. I am convinced that super-oligotrophy in connection with high oxygenation is the key to success. Chemical filtration is a useful adjunct, but is not front-line defense.

Ever since the turnaround, which was supposed to represent a renewal phase, this aquarium has kept me guessing at every turn. Details of failures can be embarrassing but instructive. This is experimentation after all. An assumption that liberal feeding of the fish would supply a densely planted tank with sufficient nitrogen and phosphorus without supplementation I think was justified, but the problem became excessive dissolved organic matter. While nitrate and phosphate were testable, DOM was only directly accessible by monitoring the ORP. While the DOM and redox are inextricably linked, with regard to the state of the environment ORP monitoring alone can be misleading. The tank's inability to resist cyanobacteria and incipient nuisance algae became the true DOM monitor before the ORP finally started to drop. The next stage in the experiment was to throw chemical filtration at the problem which averted further deterioration but proved not to be the path to full recovery. The tell-tale phenomenon as this unfolded was the surface film, the "oil slick" that persisted, although chemical filtration renewals and "big gulp" water changes tended to tamp it down. This system was merely lapsing into a state of eutrophication being maintained by conventional water quality management procedures that are actually of limited effectiveness.

This was not what I set out to do. So we change some habits and go all in with the water change strategy.
 
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Paul G

Active member
Today's numbers

pH: 6.72
ORP: 471 mV
NO3: 0.89 ppm
PO4: 0.44 ppm
Fe: 0
K: 30 ppm
dKH: 6.55
dGH: 3.58
Ca: 16.00 ppm
Mg: 5.85 ppm
Ca/Mg: 2.7/1
TDS: 270 ppm

With a full day of the larger ODE adjustment the GH and Ca/Mg numbers are holding exactly. Potassium and buffer are slightly down, probably accounting for most of the decline in TDS. K = 30 ppm and dKH = 6.55 are perfectly acceptable per se, but their decline suggests that an increase in the K2CO3 dose may be necessary now with the new ODE adjustment. I am adding a regular 20 mL dose of K2CO3 solution at 17:00 to the schedule.

I am testing iron around two hours after the first morning dose of Flourish, trying to calibrate Fe++ to the new ODE. I know that ferrous gluconate is going into the system; I would like to be able to get a detectable trace of iron at this time of day. The question, though, is not just that of iron but of the micronutrients in general, as it is necessary to compensate the new ODE adjustment for all of them. Iron is the only one that is testable; its concentration is just an index for the micronutrient components in the dose. The dosing rates for Flourish Comprehensive and Flourish Trace need to be bumped up; about 1.33 to 1.5 times is an arbitrary but cautious judgement.

Plants are growing and new Cryptocoryne volunteers are appearing.
 
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Paul G

Active member
Today's numbers

pH: 6.72
ORP: 486 mV
NO3: - n/t -
PO4: 0.34 ppm
Fe: 0.06 ppm (@ 07:16)
K: 40 ppm
dKH: 6.78
dGH: 3.58
Ca: 16:00 ppm
Mg: 5.85 ppm
Ca/Mg: 2.7/1
TDS: 280 ppm

GH and Ca/Mg numbers remain spot on! Redox, K+, and KH have returned to their normal highs. Fe++ tests non-zero one hour after first AM dose. I am accepting this state as being ideal for the habitat conditions being sought. The chemistry is calibrated for the accelerated SWCR, and confidence is high that means are at hand to fine tune the balance going forward. I am accepting 280 ppm as the normal TDS for this system. The current SWCR throughput rate is now fairly significant at 5.6 liter ODE 24/7, and the ORP is reflecting the diminished DOM.

DIN and orthophosphate are, and have for a long time been, well within oligotrophy. DO running average exceeds 100% saturation with overnight lows not less than 7 ppm O2. The principal way this aquarium has deviated from desirable conditions, and therefore the obvious reason for its lapse into eutrophication, is a period of elevated DOM not immediately detected. This resulted from excessive autochthony via fish food and illustrates the insidious nature of a pollution event wherein there is a latency in visible effects to the community, particularly obstinate algae and surface film. Every ecosystem will have a Critical Load threshold for pollutants. Based on my experience I believe the Critical Load tolerance for DOM alone is least forgiving. Recovery from environmental damage caused by DOM will be a prolonged process. As long as the plants and bio-filter survive and grow, community metabolism will finally restore health to the system. The SWCR is now rapidly ejecting DOM and a full recovery is expected soon.

SIDENOTE - WHEN TINKERING WITH FILTER FLOW RATES PAY ATTENTION TO THE DATA!

An aggravating factor in the case of this incident was destabilized CO2 with choppy pH response. Here is that trace. Return to normal occurred when pH control was switched from right probe to left probe. The circulatory dysfunction that caused this has been corrected.

 
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Paul G

Active member
Today's numbers

pH: 6.72
ORP: 470 mV
NO3: - n/t -
PO4: 0.22 ppm
Fe: 0.06 ppm (@ 07:20)
K: 40 ppm
dKH: 6.72
dGH: 3.81
Ca: 17.60 ppm
Mg: 5.86 ppm
Ca/Mg: 3.2/1
TDS: 290 ppm

GH and TDS up with a slight increase in Ca++. I topped off the Q tank, moving exactly 1.5 gallons. Also, an ODE had just completed, accounting for another nearly 1.5 gallons. Then I retested.

dGH: 3.70
Ca: 16.8 ppm
Mg: 5.85 ppm
Ca/Mg: 2.9/1
TDS: 280 ppm

The HRR is overrunning the SWCR just slightly. The balancing performance of the method is very close with the GH inclining. Correction for drift is feasible with small ad hoc water changes, the frequency of which depends on the drift rate, and thus on the balance. If the calcium enrichment accelerates, it might be necessary to remove some Reef Reactor from the HRR, but in any case, the Ca++ must overrun the balance so that concentration can be controlled by small occasional water changes. It must be recognized that perfect balance cannot be achieved as a practical matter; there is bound to be drift. Upward drift assures that correction can be attained by water changes in addition to the SWCR (always desirable).

Since the ultimate goal is automation, I do not want to get so hung up in the numbers that I become preoccupied with excessive tinkering. If the filter change schedule of two week intervals is adhered to, that would mean an attendant water change of 3 gallons at a minimum. I am looking forward to this practice keeping parameters within acceptable bounds. Attention now to getting a good balance with the SWCR and HRR rates is meant to enable this expectation with respect to GH. Variations are certainly tolerable, but the system must not be allowed to drift away entirely. I'd very much like to get this in a state wherein I am only testing every few days.
 

Paul G

Active member
Today's numbers

pH: 6.73
ORP: 467 mV
NO3: 0.5 ppm
PO4: 0.23 ppm
Fe: - n/t -
K: 40 ppm
dKH: 6.84
dGH: 3.59
Ca: 16.00 ppm
Mg: 5.85 ppm
Ca/Mg: 2.7/1

These numbers are posited as ideal target values for this aquarium. The HRR/SWCR balance seems to be holding. The following is a formalized summary.

This relationship is essentially a prediction constructed on an original determination of the volume of water discarded over a specified time period, and the rate of dissolution of the ion source. The means of achieving balance is therefore experimentally dependent on the constancy of these two factors; it is a prediction. There being no actual feed-back loops in operation by which this relationship is automatically regulated, this balancing act cannot be properly called "homeostatic". An idealized mechanism to obtain balance would be a true feedback channel governing generation of free ions based on their concentration in the water column. Homeostasis is very high stability because the feedback loop operates constantly, either by true continuity or by a regime of small discrete quanta that resembles such continuity for all practical purposes (for instance, control of CO2 diffusion as a response to pH changes). There being no simple and reliable fully automatic aquarium technology answer to this for control of GH, maintaining the balance consists of predicting the condition from known controlling factor values, and having the facility to alter those factors as required. The feedback loop is not physiologically intrinsic, so is not homeostatic; but the predictability of the system's behavior emulates homeostasis: Artificial Homeostasis. In this case, it is the timer that provides a virtual feedback loop.

SWCR, Streaming Water Change Regimen, is an automated method of discarding a highly significant portion of the waste products of environmental metabolism while supporting stability in the background chemistry and provision of important macrophyte nutrients. It is a program for artificial homeostasis. Success of the method is defined by maintenance of constant parameters for an indefinite time. The two principal balance systems in operation are the SWCR<-->CaCO3 Dissolution Reactor, and the SWCR<-->K2CO3/MgSO4 Supplementation. This regimen is an ODE (open drain event) hourly, 24 times a day. Each ODE is 150 seconds for a water volume of 5.6 liters.

The HRR, Hardness Reconstitution Reactor, consists of 1.5 kg of SeaChem Reef Reactor packed into a mechanical filter core; works as a no-bypass dissolution reactor with a water throughput velocity of 100 to 120 gph. Reef Reactor medium consists primarily of CaCO3 and is essentially an aragonite substrate type of material. Contributor of both Ca++ and CO3-- ions, this medium supports system GH and KH. This circulation loop runs constantly 24/7.

K2CO3 Supplementation consists of an aqueous solution of 150 grams (110 mL fine granular) Food Grade K2CO3 per 190 mL DW. Contributor of K+ and CO3-- ions, this supplement supports the larger part of system KH (buffer) and provides macronutrient K+ in luxury uptake availability. The daily K2CO3 solution dose is 10 mL at each of the following times: 06:00, 09:30, 13:00, 17:00, and 19:00.

MgSO4 Supplementation consists of an aqueous solution of 150 grams (140 mL coarse crystalline) USP Grade MgSO4 per 190 mL DW. Contributor of Mg++ and SO4-- ions, this supplement is, as the predominant source of secondary macronutrient Mg++, the complement with Ca++ to maintain prescribed GH. This supplement also supplies sulfate which is the source of secondary macronutrient sulfur, far in excess of requirement. The daily MgSO4 solution dose is 10 mL at each of the following times: 06:00, 09:30, 13:00, and 17:00.

TDS, Total Dissolved Solids, is the combined effect of all ions in aqueous solution. The Milwaukee Instruments MC-410 gives a direct read-out of TDS with a resolution of 10 mg/L (ppm). Today, TDA started at 280 ppm at sunrise (tank time), bumped to 290 ppm by mid-morning, then to 300 ppm by mid-afternoon, then to 310 ppm by early evening. These changes correspond to the supplement dosing schedule.

Specifications subject to change, as adjustments may be required to fine-tune the system and correct for drift.
 
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Paul G

Active member
Today's numbers

pH: 6.72
ORP: 483 mV
NO3: 0.5 ppm
PO4: 0.21 ppm
Fe: 0.21 (@07:48)
K: 40 ppm
dKH: 7.17
dGH: 3.81
Ca: 16.0 ppm
Mg: 6.83 ppm
Ca/Mg: 2.3/1
 
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Paul G

Active member
Today's numbers

pH: 6.72
ORP: 493 mV
NO3: 1.77 ppm
PO4: 0.22 ppm
Fe: 0.13 ppm (@06: 40)
K: 40 ppm
dKH: 7.28
dGH: 3.81
Ca: 15.2 ppm
Mg: 7.3 ppm
Ca/Mg: 2.1/1

Buffer appears to be overrunning SWCR. At the prevailing pH, CO2 is around 40 ppm at KH just below 7 degrees. KH > 7 is not a problem per se, but the numbers do indicate drift, and it is not necessary. Curtailing the K2CO3 dose just a bit will not measurably draw down the K+. Each of the five daily doses will be reduced from 20 mL to 15 mL, and we'll see how that goes.

As of yesterday, the 17:00 dose of MgSO4 was discontinued.

Having moved the 10 mL KNO3 dose to the pre-test AM time, the low-nitrate test kit is yielding higher numbers. Nitrate readings at this time will be highest for the day, and this is more meaningful information. No PO4 is being added; this is all autochthonous. The PO4 values have remained below 0.5 ppm for quite awhile now and is fairly stable.

To detect Fe, it is necessary to test within an hour of dosing. The results tend to be variable but it's evidence that iron is going into the system.
 

Paul G

Active member
Today's numbers

pH: 6.72
ORP: 498 mV
TDS: 300 ppm (@ 07:00)
NO3: 1.80 ppm
PO4: 0.44 ppm
Fe: 0.22 ppm (@ 07:00)
K: 40 ppd
dKH: 7.17
dGH: 3.36
Ca: 12.80 ppm
Mg: 6.83 ppm
Ca/Mg: 1.9/1
 

Paul G

Active member
Today's numbers

pH: 6.71
ORP: 503 mV
TDS: 300 ppm (@ 07:15)
NO3: - n/t -
PO4: - n/t -
K: - n/t -
Fe: 0.05 ppm (@ 07:12)
dKH: 6.95
dGH: 3.59
Ca: 16.0 ppm
Mg: 5.85 ppm
Ca/Mg: 2.7/1

Yesterday's hardness numbers looked somewhat wonky, and I did, in fact, repeat the tests for verification. The temptation was to attempt a drift correction, but I did nothing at all, anxious to see today's test results. The GH came right back to 3.59 degrees (64 ppm CaCO3), and the Ca/Mg ratio came right back to 2.7/1. Those were the numbers typical throughout last week. I am also noting that the TDS monitor has settled down to a steady 300 ppm. This state suggests that the tank chemistry is stable, at least for the moment. The weekend calcium decline and rebound to normal will have to remain unexplained, as I did nothing to cause it or relieve it! What I take from this is that this artificial homeostasis seems to function well, and that an anomalous number probably should not be interpreted as drift until the third day of clear discrepancy, at least.

Having no reason to suspect that macronutrient levels are very much different from recent trends I did not test them today.

Filter changes are due this week. I am interested to see what effect this routine maintenance procedure will have on these numbers.

Redox is very high and I am interpreting this as diminishment of DOM. This is owing to conservative feeding practices and to the greatly accelerated SWCR.
 

Paul G

Active member
I added a third 10 mL dose of Flourish at 06:30 to the schedule.

Today's numbers

pH: 6.71
ORP: 508 mV
TDS: 290 ppm (@ 07:45)
NO3: 2.66 ppm
PO4: 0.49 ppm
Fe: 0.13 ppm (@ 07:44)
K: 40 ppm
dKH: 6.83
dGH: 3.70
Ca: 15.2 ppm
Mg: 6.83 ppm
Ca/Mg: 2.2/1
 
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