October 2026 — 29-Gallon Aquarium R&D Journal

October 2026

October marked another interesting chapter in the 29-gallon Balance Experiment.

For the first time in months, the aquarium went an entire 30-day maintenance interval without nitrate climbing beyond the low range of our hobby test kit.

The month also brought several developments:

The aquarium survived a two-week vacation with minimal feeding.
The betta developed concerning symptoms that required closer observation.
We completed our first major return-side plumbing inspection.
A preventive water change was performed after 30 days.
The pothos and Java moss received light trimming.
Black beard algae remained a concern.
The Finnex display lighting was increased to maximum brightness.
We began preparing for November’s GH, KH, TDS, and distilled-water experiments.

Perhaps the biggest lesson was that the aquarium’s behavior continues to evolve. Its current nutrient accumulation rate is very different from the early stages of the experiment.

However, the aquarium also has fewer fish than it did during the original baseline. That difference must be considered before attributing the slower nitrate accumulation to improvements in filtration or maintenance alone.

October 10 — Returning From Vacation

After approximately two weeks away, I returned to the aquarium.

Water parameters

Nitrate: approximately 5–10 ppm
Temperature: 77.2°F
Top-off: 10 containers

Previous maintenance

September 26:

Approximately 99% sump water change
Approximately 75% display water change
Post-water-change nitrate: approximately 0 ppm

Fourteen days later, nitrate had only reached approximately 5–10 ppm.

The fish appeared to be swimming normally, and there were no immediately obvious problems with the aquarium.

Vacation Feeding Experiment

While I was away, a neighbor was responsible for feeding the fish.

The instructions were deliberately conservative:

Feed only once or twice per week.
Use very small portions.
Avoid excessive feeding.

One important detail was that the neighbor was not instructed to shut off the return pump.

Normally, when I feed the aquarium, I temporarily stop the return pump so food is not immediately carried away.

However, the plumbing has a check valve that has previously failed. Safely shutting down the return pump requires manually closing a ball valve to prevent excessive back-siphoning.

I did not want an unfamiliar caretaker operating that system.

Initial observation: The aquarium returned from vacation with low nitrate and no obvious community-wide distress.

However, a health concern involving the betta became apparent several days later.

This is an important reminder that stable water parameters do not automatically guarantee that every individual fish is receiving adequate nutrition.

October 13 — Betta Health Concern

I noticed that the betta was behaving differently.

Symptoms included:

Spending significantly more time resting on the substrate
Reduced activity
Appearing noticeably thinner than normal
Less active swimming

The betta is not a particularly strong or aggressive feeder.

Because the return pump remained operating while the neighbor fed the aquarium, I began wondering whether the betta had received enough food during the vacation.

Other fish could have consumed much of the food before the betta reached it.

Temporary Feeding Adjustment

I decided to increase feeding opportunities temporarily, focusing on making sure the betta received food directly.

The strategy was to offer small, controlled portions rather than increasing food for the entire aquarium.

This was treated as a possible nutritional recovery plan, not a confirmed diagnosis.

October 15 — Betta Facial Growth Documented

Water parameters

Nitrate: approximately 10 ppm
Temperature: 77°F

The betta remained lethargic but continued eating.

I also documented an important observation that I had initially forgotten to report.

A growth had developed on the side of the betta’s face, near the head and gill-cover region.

I had first noticed it approximately three weeks earlier, meaning the growth was present before the vacation.

A photograph was taken and reviewed.

Physical observations

Rounded, localized facial swelling/growth
No obvious cotton-like appearance in the photograph
Fish still eating
More frequent bottom resting
Fish appeared thinner than usual
No obvious generalized body distortion reported

The precise cause of the growth could not be determined from the photograph.

Possibilities included several types of localized lesions, but no definitive diagnosis was established.

Important distinction

The facial growth existed before the reduced vacation feeding.

Therefore, insufficient food intake might explain some weight loss or weakness, but it cannot explain the original development of the facial growth.

No medication was started based on the photograph alone.

With shrimp, snails, and plants in the aquarium, unnecessary display-tank medication also presents additional risks.

The plan was to continue monitoring appetite, breathing, body condition, activity, and changes in the growth.

October 20 — Betta Showing Some Improvement

Water parameters

Nitrate: approximately 5–10 ppm
Temperature: 76.4°F at observation
Aquarium had generally been around 77°F
Top-off: 9 containers

The betta appeared somewhat better.

The most noticeable improvement was that he was spending less time lying on the substrate.

His condition was not considered fully resolved, but there was a modest improvement in activity.

The improvement followed a period of increased attention to feeding.

This supports the possibility that inadequate food intake contributed to his condition, but does not establish that underfeeding was the only cause.

The facial growth remained an unresolved health observation.

Nitrate Observation

Nitrate continued to test in the low range, with no confirmed upward trend.

At this stage, the aquarium was approximately 24 days beyond its September 26 water change.

October 26 — Monthly Water Change and Return-Side Maintenance

October 26 was exactly 30 days after the previous major water change.

Pre-maintenance nitrate: approximately 5–10 ppm

This was significant because, during the early Balance Experiment, the same aquarium had reached approximately 40 ppm within roughly 12–13 days.

The current aquarium was now completing much longer intervals without accumulating comparable nitrate levels.

The water change was performed for preventive maintenance, not because nitrate had become elevated.

Why perform a water change with low nitrate?

Several factors prompted the maintenance:

Thirty days since the previous water change
Low operating water level from evaporation
Visible algae accumulation on the aquarium glass
Planned inspection of the return-side plumbing
Planned check-valve maintenance
General system refresh

The intention was to maintain water chemistry and equipment reliability rather than wait for nitrate to reach an arbitrary threshold.

Water Change Completed

Display: approximately 50%
Sump: essentially 100%

Prime was added for the new water.

Seachem Stability was also added following the cleaning work.

Return-Side Plumbing Inspection

Back in August, the aquarium’s drain plumbing contained a surprisingly large amount of accumulated organic sludge.

That discovery raised an important question:

Was the return side hiding similar debris?

During the October 26 maintenance, the return-side tubing was inspected and cleaned.

The findings were quite different.

Return tubing observations

Some light coating/biofilm present
Material came off easily
No significant compacted sludge
Much cleaner than the drain-side plumbing inspected in August

The coating appeared consistent with ordinary wet-surface biofilm, rather than evidence of a major hidden sludge reservoir.

Return Pump Maintenance

The return pump was also serviced.

Confirmed cleaning included:

Impeller/propeller
Front faceplate
Accessible pump surfaces involved in the service

The pump’s vibration mat was also reviewed for positioning during this maintenance period.

The check valve was on the maintenance plan, although its completed cleaning was not separately confirmed in the log.

Drain Side vs. Return Side

This became one of the most useful equipment comparisons in the Balance Experiment.

August — Drain Plumbing

Heavy organic debris accumulation
Thick, compacted sludge
Required substantial scrubbing
Approximately 90–95% of the visible material removed

October — Return Plumbing

Light biofilm
Easily removed
No comparable sludge accumulation

These observations show that debris accumulation was not evenly distributed throughout the aquarium’s plumbing.

The drain side had been a much more significant accumulation point.

That does not prove the original drain sludge caused the previous nitrate pattern, but it supports including drain-line inspection as part of this particular system’s maintenance routine.

October 26 — Plant Trimming

During the same maintenance session, I also lightly trimmed:

Pothos
Java moss

The trimming was modest rather than a major removal of plant mass.

R&D Observation

When plant growth is physically removed from an aquarium, nutrients stored within that tissue leave the system.

This provides a form of nutrient export.

However, because only a small amount of material was removed, the impact on the aquarium’s overall nitrate concentration cannot be quantified.

October 27 — Fertilizer and Betta Observation

Fertilizer

NilocG Thrive S
4 pumps
Normal Tuesday weekly dose

The aquarium generally looked normal.

The betta also appeared considerably closer to his usual behavior.

He was eating normally and no longer seemed as consistently lethargic as earlier in the month.

However, he continued to rest more frequently than he historically had.

The facial growth remained part of the ongoing health observation.

Lighting Experiment

Around this period, I began experimenting with stronger lighting.

The aquarium uses a Finnex Planted+ 24/7 CC fixture.

Previously, the LEDs had operated under a customized intensity configuration.

The new experiment involved activating maximum LED brightness.

The purpose was to investigate whether increased light penetration through the growing plant canopy could improve plant growth and overall system balance.

October 30 — Post-Maintenance Nitrate Check

Water parameters

Nitrate: approximately 5 ppm or lower
Temperature: 76.4°F
Top-off: 4 containers

This was Day 4 since the October 26 water change.

The reading remained in the very low range.

Because an immediate two-hour post-water-change nitrate measurement was not recorded on October 26, this was the first documented nitrate checkpoint of the new cycle.

No significant nitrate accumulation was detected.

October 31 — Lighting Configuration Confirmed

By the end of October, the lighting experiment had been running for approximately one week.

The approximate activation date was October 24.

The configuration was confirmed through the Apple Home smart-plug automation.

Lighting hardware

Finnex Planted+ 24/7 CC

Controller

Meross smart plug connected to Apple Home

October schedule

Lights ON: 9:45 AM
Lights OFF: 6:15 PM
Total photoperiod: 8 hours 30 minutes

Brightness

MAX LED output
Not using the fixture’s automatic 24/7 cycle
Smart plug controls the daily power schedule

This is important because the experiment increased light intensity without intentionally extending the daily lighting period.

Why Increase Lighting?

The aquarium has a substantial amount of plant growth, including taller plants that can shade lower leaves.

The idea was to test whether stronger lighting could improve penetration through this vegetation.

However, the aquarium does not use injected CO₂.

Higher lighting intensity can increase plant demand for carbon and nutrients.

If those demands cannot be met, increased brightness may not translate into healthier growth and can encourage additional algae.

The experiment therefore needs to be judged by actual plant and algae response, not brightness alone.

October 31 — Black Beard Algae and Flow Observations

Black beard algae remained present.

Earlier in the year, the algae had become more controlled.

However, new or recurring BBA was observed before the lighting was switched to MAX.

That chronological detail matters.

MAX lighting did not initiate the documented recurrence of BBA, although it could potentially influence future growth.

Return Nozzle Position

The aquarium was still using its Random Flow Generator return nozzle.

By the end of October, the nozzle was oriented almost vertically upward, very close to the rear glass.

It was not directed toward the plants.

This likely concentrated some movement near the surface, but the actual circulation pattern throughout the display had not been measured.

The possibility of uneven circulation was one reason for considering a different return arrangement.

Planned DIY Spray Bar

A custom PVC spray bar was being designed.

The proposed design would:

Run along the right side of the display, front to back
Distribute water across the aquarium
Use multiple angled outlets
Reduce reliance on a single concentrated return
Sit near the waterline
Incorporate a more effective siphon-break arrangement

One proposed outlet layout included nine holes, with four aimed in one direction, four in the other, and a central outlet.

This was still a design concept rather than an installed system.

The spray bar’s most important objective is plumbing safety.

The aquarium has previously experienced check-valve failures and back-siphoning problems.

The system must be capable of handling pump shutdown without flooding, even if the check valve fails.

No spray bar installation was completed during October.

October Nitrate Timeline

Date	Nitrate	Context
October 10	5–10 ppm	Return from vacation; Day 14
October 15	~10 ppm	Betta health observation
October 20	5–10 ppm	Day 24
October 26	5–10 ppm	Day 30, before maintenance
October 30	~5 ppm or lower	Day 4 after water change

Important Interpretation

Nitrate stayed low throughout the entire October water-change interval.

The readings between approximately 5 and 10 ppm are difficult to distinguish precisely using the API liquid color chart.

Small apparent decreases should not automatically be interpreted as real biological nitrate removal.

The reliable observation is that nitrate remained in the low range without a confirmed rise toward 40 ppm.

October Water Change Summary

Confirmed major water changes: 1

October 26

Display: approximately 50%
Sump: essentially 100%
Previous water change: September 26
Interval: 30 days
Pre-water-change nitrate: approximately 5–10 ppm

This was a preventive maintenance reset.

There was no confirmed nitrate-triggered water change in October.

October Top-Off Summary

Date	Containers
October 10	10
October 20	9
October 30	4
Total documented	23

The container’s exact volume has not been established, so the total is recorded in container units rather than estimated gallons.

At the end of October, the switch to distilled-water top-offs had not yet begun.

Conditioned tap water remained the established top-off source pending the GH, KH, and TDS baseline.

October Fertilizer

Product:

NilocG Thrive S — Shrimp Specific All-in-One

Established routine:

Tuesday
4 pumps weekly

Confirmed recorded October dose

October 27:

4 pumps

The routine remained established, but earlier October doses were not individually documented in the available log, so they are not being reconstructed as confirmed events.

October Feeding and Livestock

Vacation Feeding

A neighbor fed the aquarium approximately once or twice weekly during the vacation, using small portions as instructed.

The exact individual feedings and amounts were not recorded.

Betta Recovery Feeding

On October 13, I began planning additional targeted feedings for the betta after observing weight loss and reduced activity.

The goal was to ensure that the betta received food directly, rather than allowing stronger or faster fish to consume everything first.

By October 20, modest improvement was observed.

By October 27, the betta appeared generally closer to normal, although increased resting continued.

The facial growth remained unresolved.

Other Livestock

No additional fish or shrimp purchases were recorded in October.

The Blue Diamond shrimp introduced at Aquashella on September 13 remained part of the aquarium’s livestock inventory.

A precise surviving count was not established during October.

The Biggest October Finding: A Different Nitrate Baseline

When the Balance Experiment began in April, the aquarium supported a larger fish population.

During the first relatively clean nitrate cycles:

Nitrate started around 5–10 ppm after a water change.
It climbed toward approximately 40 ppm in roughly 12–13 days.

By October:

The aquarium went 30 days between water changes.
Nitrate was still approximately 5–10 ppm before maintenance.

This is a substantial difference in observed nitrate accumulation.

However, an important variable is the aquarium’s significantly reduced fish population.

Earlier livestock losses reduced the number of fish producing waste and the amount of food required.

Possible Contributors

1. Reduced fish bioload

Fewer fish generally means less waste production and lower total feeding demand.

This is probably one of the more important changes between the original baseline and the current system.

2. Reduced and controlled feeding

The feeding schedule was reduced during previous months.

Less uneaten food and organic input may reduce the amount of nitrogen entering the system.

3. August drain-plumbing cleaning

Heavy accumulated organic sludge was removed from the drain plumbing.

That material could previously have contributed to ongoing nutrient generation as it decomposed.

However, its contribution was not independently measured.

4. Plant growth and nutrient uptake

The aquarium contains numerous aquatic plants, Java moss, and pothos.

Growing plants can absorb nitrogen and other dissolved nutrients.

Trimming and removing plant material exports nutrients stored in that tissue.

5. System maturation and maintenance improvements

The aquarium has experienced changes in filtration maintenance, water movement, and operating routines.

These may influence how organic waste is captured and processed.

What We Cannot Conclude

We cannot claim that cleaning the drain plumbing alone caused the slower nitrate accumulation.

We also cannot calculate how much nitrate reduction resulted from the plants, feeding changes, or reduced livestock.

Several variables changed during the same period.

The evidence shows a clear difference between the historical and current system, but it does not isolate the cause.

October R&D Lessons

1. Low Nitrate Does Not Mean Maintenance Is Unnecessary

October demonstrated that water changes can remain valuable even when nitrate is low.

The 30-day water change refreshed the aquarium and provided an opportunity to inspect equipment, remove algae, and perform plant maintenance.

2. Fish Health Requires More Than Water Testing

The betta developed noticeable lethargy and weight loss while nitrate remained low.

This reinforced the importance of observing individual feeding success, body condition, behavior, and visible lesions.

Good water parameters do not rule out illness or inadequate food intake.

3. Plumbing Accumulation Is Uneven

The August drain-line cleaning and October return-line inspection provided an interesting comparison.

The drain side contained heavy sludge.

The return side contained comparatively little buildup.

The location and behavior of organic debris matter when designing an aquarium maintenance routine.

4. Feeding Practices Matter

Reduced feeding during vacation coincided with low nitrate, but it also raised a potential nutritional concern for the slower-feeding betta.

A low nutrient load is not the only goal.

Every fish still needs access to adequate nutrition.

5. More Light Is Not Automatically Better

Increasing LED brightness without increasing CO₂ availability may change the balance between plant growth and algae.

The new MAX-lighting experiment must therefore be evaluated over time.

6. Baselines Change as the Aquarium Changes

The original spring nitrate baseline belonged to an aquarium with a different livestock population, feeding routine, filtration condition, and maintenance history.

The current baseline describes the aquarium as it exists today.

Both sets of data are useful, but they should not be treated as identical operating conditions.

Looking Ahead — November 2026

November will begin another phase of the Balance Experiment.

The central research focus is shifting from nitrate accumulation toward mineral and water-chemistry stability.

GH, KH, pH and TDS Baseline

A liquid GH/KH testing kit has been ordered, with arrival expected in early November.

The plan is to measure:

Aquarium water

Source tap water

Distilled water

TDS verification

After documenting the baseline, evaporation top-offs will transition from conditioned tap water to distilled water.

Normal water changes will continue using conditioned tap water.

The objective is to observe whether GH, KH, pH, and TDS change as mineral-containing top-offs are eliminated.

New Lighting Schedule

Beginning November 1, the planned schedule is:

ON: 10:15 AM
OFF: 6:15 PM
Total: 8 hours

LED output remains at MAX while the experiment is monitored.

This reduces the daily photoperiod by 30 minutes compared with October’s schedule.

New Feeding Schedule

The planned regular prepared-feeding days are:

Sunday
Tuesday
Thursday

No routine prepared feeding is scheduled on Monday, Wednesday, Friday, or Saturday.

Individual targeted feeding may still be necessary depending on the betta’s condition.

DIY Spray Bar

The proposed spray bar remains under development.

Its installation will be documented separately once completed.

The project will focus on improving water distribution and correcting the return’s siphon-break configuration.

Testing Frequency

With several months of low nitrate readings established, nitrate testing may transition from approximately every three days to weekly monitoring.

GH, KH, pH, and TDS will initially receive more frequent attention as the new baseline is established.

Final Reflection — October 2026

October reinforced why this experiment began in the first place.

A year ago, I might have looked at nitrate levels, changed water because the calendar said it was time, and moved on.

Now, every maintenance session tells us something about how this particular ecosystem operates.

We know the aquarium’s current nitrate accumulation is much slower than it was during the first baseline.

We know that the drain plumbing accumulated substantial organic waste while the return plumbing remained comparatively clean.

We know that an aquarium can have low nitrate and still have an individual fish experiencing a health problem.

And we know that changes to light, feeding, livestock, plants, and maintenance all have to be considered together.

The purpose of the Balance Experiment was never to eliminate water changes or chase a perfect nitrate number.

It was to understand the aquarium well enough to make maintenance decisions based on observations rather than assumptions.

October moved that understanding forward.

November’s next question: What happens to our aquarium’s mineral chemistry when we stop replacing evaporation with tap water and begin using distilled water instead?

That is the next chapter of the experiment.

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