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Yugang
Supporting Expert in Residence Rockstar Article Contributor
Last reply · posted in Equipment Discussions
Several members of this forum have greatly contributed to testing the concept of Horizontal CO2 Reactor , and I am so happy that collectively we have succeeded to push some true innovation. @Unexpected successfully pioneered the first horizontal reactor on his bigger tank, was kind enough to call it ‘Yugang reactor’ and inspired several followers with that. Also to mention @RickyV who took CO2 injection to a new level with a 1000-gallon system, achieving a 1.0 pH drop in just 38 minutes. Thank you to all who have contributed, and I believe hobbyist will find most answers in the Horizontal CO2 Reactor thread on this forum and hopefully feel that CO2 is easier than it used to be with bubble reactors.

My journey started about 2 years ago, when I was doing some measurements and calculations on my bubble reactor and got to the idea of the CO2 Spray Bar. I built probably 10 versions / prototypes of CO2 Spray Bar, spent many days measuring pH profiles, so that I could share my insights with the community on UKAPS. The horizontal reactor is based on the physics principles of the CO2 Spray Bar, and test results are applicable to both. I was at the time so happy with my CO2 Spray Bar that I gave no priority to building the horizontal reactor and thanks again to @Unexpected for his initiative and courage. I am currently also using the horizontal reactor, but my love and in certain situations preference for CO2 Spray Bar remains.

I discovered this morning that both threads on CO2 Spray Bar and Horizontal CO2 reactor have now been removed by the UKAPS admins. This may have happened in the past few weeks, not sure as I am not a regular UKAPS visitor anymore. These threads represent probably several hundred hours work, aiming to be a lasting and valuable contribution to the hobby, lots of measurement data, comparisons and calculations, and many pages of posts from fellow hobbyists. Even posts in several journals featuring the CO2 Spray Bar or Horizontal Reactor have been deleted or edited by admins. Thumbs up to forum rules, but very few will disagree that these all stand or fall with forum governance and integrity to individual members as well as the community.

While having the Horizontal CO2 Reactor now well documented on this forum, I believe it is a loss for the hobby if we would lose the insights on CO2 Spray Bar. It offers the same performance as the Horizontal CO2 Reactor, can be made for perhaps 5-10 USD and one hour DIY work. When I have more time I may create a new thread on this forum, with similar detail as what was deleted in UKAPS, with various prototypes and measurements. For now I hope it is useful if I just post a quick summary.

The first prototype CO2 Spray Bar, as I was testing late 2021 / early 2022.

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The CO2 Spray Bar in the front of the tank, was in my tank barely visible. In my 200 liter tank I used a transparent half pipe, and achieved 1.5 pH drop with very good stability. It is from the experiments with the Spray Bar that I took the 17.7 ratio for the calculation of Horizontal Reactor dimension.

Some forum members pushed back on the idea having anything in the front, so I started experimenting with CO2 Spray Bar in the back of the tank.

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I hope the above pictures help to understand the CO2 Spray Bar, and perhaps inspire fellow hobbyists to try it in their tanks. Having a simple half-pipe in a tank is easier than building an inline horizontal CO2 reactor, and may be especially attractive for small tanks.

For any further questions or help, please post below or send me an PM. I may start a more detailed thread when I have a bit more time and/or see there is interest from fellow hobbyists.

Thank you for reading, and thank you to ScapeCrunch for giving us a good home for our hobby.
58 Replies · 10875 views
JayP
Supporting I Donated 2026 Rockstar
Last reply · posted in Lounge
Amazon prime day is less than 2 weeks away so I thought I'd start a thread in advance to discuss any bargains we might see.

The reason this came to mind now was that I just happen to be browsing for other things when I noticed this small curved edge low iron tank pop up. I would probably buy one of these if it drops even lower for prime day.

10 Gallon Ultra Clear Glass Rimless Curved Edge Aquarium
28 Replies · 307 views
Dennis Wong
I Donated 2026 Expert in Residence MOTM Winner
Last reply · posted in Journals
I came into some Hygrophila polysperma "white" by Tropica recently. Grew it out and it seems to be able to be shaped into good midground bushes so I decided to create a layout to showcase it. Contemplated whether to use it as the only white plant in the tank, but decided to use some Anubias white petite as well so that the white polysperma doesn't stand out awkwardly.

2hrAquaristDSCF1921 hygrophila white.webp
24 Replies · 1177 views
R
Last reply · posted in Journals
Hi guys!

I'm new here, but not entirely new to planted tanks though I've been out of the hobby for the better part of the last decade between kids and moving a couple of times - but finally in a spot where I can do something again. I'm mostly going to be making things up as I go along, but plan on a lot of automation (I want to integrate everything into home assistant) and a lot of DIY as I love the challenge of building things out myself.

The starting point:

I picked up a 90P rimless, low-iron tank on a great deal.

Media (1).webp

I have a rough idea in my head for a stand to be built from plywood - just have a couple other house projects to finish off before starting that built.

Wife says I can only have one aquarium, so for this tank, I want to go all out with a sump to allow for auto top off, and auto water changes, auto fertilizer dosing etc. etc. I have half a plan in my mind.

I've also started on the light fixture which I've modeled up in CAD, and plan on making out of an 8020 extrusion, and some 3D printed bits.
Screenshot 2026-06-01 092809.webp
I'm using bridgelux gen 3 thrive CW (3000k) and WW (5000k) LED strips which have super high CRI at 98+ along with some specific XPE2 wavelengths that I'll solder onto some starboards. Far Red (730nm), Red (654nm), Cyan (495nm), Blue (455nm), Visible UV (415nm). Each segment of the white channels will be on its own driver so I can adjust left to right brightness in thirds, and each colour channel on its own driver so I can vary each channel on a time-based approach.

These will be run from a custom PCB board with Meanwell N-LDD drivers, and will run ESPHome on an ESP32 so it can link up with my Home Assistant installation.
1780321317096.webp

That's it for now, this will probably be a very slow build so be warned if you follow along!
35 Replies · 1414 views
gnatster
Supporting I Donated 2026
Last reply · posted in Equipment Discussions
Tried to open the app to change a setting. Goes to a login screen. Checked Chihiros support, and it seems to be an issue with the latest version of the app. The issue appears to be widespread.

Discussion on the Chihiros site.
8 Replies · 107 views
Art
Art
Staff member I Donated 2026 Founding Member
Last reply · posted in Forum News/Feedback
This is the future home for the announcements when someone obtains an achievement badge. Let the games begin!
1984 Replies · 48457 views
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nivliw
Last reply · posted in Planted Aquarium Discussion
I'd like to hear other people's thoughts on using pH drop to estimate CO₂ levels.


I'm in a rather strange situation. First of all, I use two good-quality digital pH meters, both properly calibrated and well maintained. I've been using this type of equipment for years because, before getting into aquariums, I was (and still am) heavily involved in hydroponics.


Anyway, here's the situation:


My fully degassed pH (water left degassing indoors for 72 hours) is 7.6. I know that degassing indoors theoretically results in a higher equilibrium CO₂ concentration than the commonly referenced 0.6 ppm achieved outdoors, but let's use that as a reference point.


With CO₂ running, the aquarium reaches a pH of 5.6, giving me a pH drop of 2.0.


Using the standard ph drop relationship and assuming 0.6 ppm CO₂ at equilibrium, that would suggest roughly 60 ppm CO₂.


However, both on this forum and in various Facebook groups, I often see people reporting pH drops of around 1.0–1.4. Some have even claimed to measure about 60 ppm CO₂ with a Hanna meter while having only a 1.4 pH drop, using water degassed outdoors.


If that were true, then extrapolating from those numbers would suggest that my tank is running at something like 240 ppm CO₂, which seems highly unlikely. My fish appear perfectly fine, and my drop checkers aren't even yellow. In fact, I have three different drop checkers in the tank, using different indicator solutions and placed in different locations, just out of curiosity.


So I'm wondering:


  • Do you think the pH drop method is being misinterpreted by many hobbyists?
  • Could there be something fundamentally wrong with the assumptions behind comparing pH drops between different tanks?
  • Has anyone here measured dissolved CO₂ directly and compared it against pH drop calculations?

I'd really be interested to hear your thoughts on this rather confusing situation.
10 Replies · 130 views
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Art
Art
Staff member I Donated 2026 Founding Member
Last reply · posted in Planted Aquarium Discussion

THE official "what did you do to your tank(s) today" thread!​

Happy Will Ferrell GIF


Let's keep it real by sharing our daily routine. Post daily if you want. It's nice to check in with fellow aquatic gardeners.
337 Replies · 19050 views
hamfist
Last reply · posted in Equipment Discussions
I've just spotted these latest Hygger luminaire lights.

All the bumf seems to claim that they only have RGB LEDs (all 5054 type). Very reasonable prices. Is this a complete bargain for a genuine RGB light ? Or is there a catch ?? THis is way off my areas of expertise.

14 Replies · 536 views
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Art
Art
Staff member I Donated 2026 Founding Member
· posted in Meet & Greet Forum
Welcome to ScapeCrunch, @Stonedwriterbagel!
We would love to get to know you. Please tell us about yourself. What tank do you have?
0 Replies · 10 views
Dennis Wong
I Donated 2026 Expert in Residence MOTM Winner
Last reply · posted in Planted Aquarium Discussion

I have good nutrient, CO2 and light levels, why do my plants still grow poorly

Many hobbyists spend time perfecting tank parameters, nutrient, light and CO2 levels, thinking that this automatically translates into optimal plant growth. While these factors are important, there are many other factors that affect plant growth.

Replanting_1.png


For example above we have two groups of Lysimachia parvifolia growing side by side. Both groups have access to the same parameters, CO2, light, nutrients, substrate. However, the group on the right is growing poorly with darker, melting leaves and the group on the left is growing super vibrant red, with hardly a blemish.

This is not due to some arcane reason such as water flow hitting one group but not the other. The reason here is much simpler - the group on the right has been trimmed back repeatedly and allowed to grow in the same spot for a few months, while the group on the left was uprooted in the last month, divided and replanted. Overcrowding, both above and below the substrate, resulted in poorer quality new leaves being produced for the group of the right. This poor growth happened despite great growth parameters, a ton of CO2 and nutrients in the water column etc.

Different plants have different tolerances for overcrowding and aging. Some plant species regenerate well from repeated trimming cycles, others need replanting more frequently. Having great growth conditions delay deterioration of old growth, but most plants grow more optimally with regular replanting to clear congested rootzones and old growth.

Trimming and replanting cycles

The exact number of trimming cycles each species can regenerate from, and the time it takes for old growth and root zone congestion to take effect is different for each aquarium environment. Generally, if aquarium conditions are more spacious, and there is more substrate depth and stable growth conditions, plants can grow in one spot longer. Stressful growth conditions, poor nutrient/CO2 levels and even poor microbial balance accelerate deterioration of old growth.

Interestingly, on the opposite end, overcrowding and root zone congestion also happens more quickly in fast growth aquariums. Hobbyists that throw a ton of nutrients and CO2 at their plants run headfirst into the brick wall that is overcrowding. This can be countered somewhat by using a portion of slower growing plants in an aquarium. The slower growing plants can be worked less often, while the fast growers are on a more regular replanting cycle.

Many aquascapers avoid stem plants because they require much more frequent replanting to grow well. Species such as Anubias, Bucephalandra and Cryptocoryne species on the other hand, have extremely long replanting cycles, and can grow for years without needing to be uprooted.

2hrAquaristDSCF8006E_Full_tank_show.jpg


In this stem plant heavy aquascape that is around 7 months old, every single plant cluster has been replanted at least once. A sample of the replanting cycle for each species:
  • Rotala blood red SG - every 4 months
  • Rotala macrandra mini type 4 - every month
  • Lysimachia parvifolia - every 2-3 months
  • Xyris difformis - every 5-6 months
  • Elatine triandra - every month
  • Rotala florida - every 3-4 months
  • Staurogyne purple - every 5 months
Uprooting_and_replanting_banner_3f78a62d-e80e-4698-ad77-42fe9135e4e3.jpg


Uprooting, cleaning, replanting:

2hrAquarist15_1024x1024.jpg


To refresh stem plant bushes, we will replant the fresh tops of the plants, while discarding the older bottom portions.

The first step is to uproot the entire stem plant bush. To control the mess when pulling up the soil, we recommend using a water siphon to vacuum the area when pulling up plants. The siphon should be held very close to the point where the plant is being pulled up to catch the soil debris.

We will try to remove as much of the old root system as possible and also remove any organic debris that has accumulated in the area. While organic debris contributes small amounts of nutrients through decomposition, a build-up of organic debris will interfere with root formation for more delicate plants and will also trigger algae. To stir up the organic debris, we use a turkey baster to spray jets of water onto the substrate while vacuuming with a siphon. The aquasoil should look clean before we start replanting.

Mini_macrandra_type_IV_green.jpg

The next step is to sort the uprooted stems and select only the healthiest heads for replanting. (A) is a middle portion and already has several branches. It is a poor choice as it will give rise to very uneven growth. (B) is a weak cutting- observe how thin the stem is, and the lack of colour. If replanted, it has a lower chance of success. (C) is ideal. A thick, singular healthy top with healthy new leaves.

2hrAquarist16_1024x1024.jpg


Enriching the substrate with new aquasoil

When plants are uprooted, we can take the chance to enrich the substrate. There are two main ways to replenish depleted aqua soils. The first is to use nitrogen-rich root tabs. The second is to add fresh ammonia-rich aquasoil periodically. A good rate is adding 1% of new ammonia-rich aquasoil per month. For example, if you have 30kg of aquasoil in an aquarium, adding around 300 grams per month will work well. You can add new aquasoil during plant replanting cycles. Simply remove a portion of old aquasoil with a water siphon or spoon, then add and mix in the new aquasoil. This method may be cheaper than using root tabs in the long run

Add new aquasoil
adding new aquasoil


Replanting entire planted aquariums regularly is not feasible for most aquarists. So having an aquascape consisting solely of fast growing stem plants can be a nightmare when overcrowding and age sets in. Aquarists should plant a mix of slower growing species and species that do not need frequent trimming/replanting. Then the fast growing bunches can be replanted on a rotation basis - only one species is replanted during each weekly water change for example.Replanting work requires skill and dexterity. It is often difficult for beginners to manage, until some experience is gained. It becomes much easier with practice and time.

In this aquarium, Rotala florida, Xyris difformis, Syngonanthus species are all plants that can grow for months without replanting.

2hrAquaristDSCF7609E_4ft_side.jpg


With consistent maintenance, aqua soils do not need to be replaced. The aqua soil in this aquarium is 1.5 years old APT Feast. Regular enrichment and clearing of detritus allows the substrate to perform like new. By renewing plant growth continually through replanting, and enrichment, planted aquariums also become more algae resistant.

This article is a slightly condensed version as I know folks don't like to be redirected, the full article can be found here:
Good parameters, Good CO2, Good light, Poor plant growth?
20 Replies · 586 views
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