We are ScapeCrunch, the place where planted aquarium hobbyists come to build relationships and support each other. When you're tired of doom scrolling, you've found your home here.
A couple of years ago I had enough of diffusers in my tank and researched options for CO2 reactors. The most popular, used for decades already, were the Cerges and Rex Griggs style where bubbles are injected into a vertical water column with a waterflow that keeps the CO2 bubbles long enough moving around to get fully dissolved. Aiming to optimize these reactors many variations were tried including bio balls, venturis, needle wheels, sponges, diffusers, and vortexes.
The optimization of a CO2 reactor is to have:
Sufficient CO2 absorption capacity for a given size of the tank and a given target CO2 ppm.
Ease to set up, leak-free, robust build.
No noise.
No CO2 bubbles escaping into the tank, 100% efficiency.
Minimal flow reduction of water pump, or cannister filter.
Minimal or no maintenance, wear or moving parts.
Low cost of purchase and maintenance.
Sera promotes their reactor as
“The new sera flore CO2 active reactors 500 and 1000 with twin rotor supersede the generation of static CO2 reactors. The rotors, the upper one of which is designed as a lamella rotor (6.3), ensure strong blending of CO2 with the aquarium water, allowing to dissolve several hundred CO2 bubbles per minute.”
“The sera active reactors are designed for optimized currents, provide excellent performance capacity, and can completely dissolve even large amounts of CO2. They can entirely be disassembled and are therefore easy to maintain and clean.”
So how does the Sera concept differ from the Rex Griggs and Cerges concept:
While in the Rex Griggs CO2 bubbles are injected into the water column (typically half-way), the Sera reactor (quote from the manual) “The water current (4.1) of the pump drives the double rotor (4.2) integrated in the reactor, which disperses CO2 introduced from the pressure gas bottle (4.3) so finely that it entirely dissolves in water. Even large amounts of CO2 can be dissolved entirely if required, allowing to supply even large, densely planted aquariums with CO2 economically” (end quote).
As the Sera double rotor is in the vertical water column, it will drive a rotation in the reactors water column.
A couple of years ago, after a careful review I decided not to buy this reactor. As I do not own it, I refer to the user manual and this Youtube video.
So how much CO2 does this reactor inject, and for what tank size is it suitable?
The ‘reviewer’ in the Youtube video uses the reactor on a 70 l tank, and we can see that there is only CO2 in the top of his reactor while no CO2 bubbles in the water column. This reminds me of ‘test driving’ a car while being parked in the dealer’s showroom, and extrapolating that experience to what it must be like on the highway.
The Sera manual says “The sera flore CO2 active reactor 500 is suitable for freshwater aquariums between 250 l (66 US gal.) and 600 l (159 US gal.). We recommend the sera flore CO2 active reactor 1000 for larger or densely planted aquariums” (end quote) but it does not specify any CO2 ppm targets. Reading further we find some vague reference “The performance capacity of the reactor is sufficient to create a pH value of 5.9 if the unit is operated without limiting” (end quote), but no reference is made to degassed pH value or pH drop and the statement is therefore meaningless.
So how about ease of installation? For some reason, even on this rather complex build, Sera did not include a degas valve. We see in the video, time stamp 5:40, that a big air pocket remains after initial filling with water, and per instruction in the manual “You must briefly turn the unit around or hold it upside down as to remove air. This will allow air to escape through the outlet tube near the bottom of the reactor. Repeat this process until there is no air left in- side the reactor if necessary. Then the sera active reactor 500 or 1000 is brought back into an upright operation position and fastened” (end quote) the reviewer holds the reactor upside down in his cabinet and is fortunate that his tubes are long and flexible enough for doing that. The problem is that this is not a one-time hassle, as any vertical reactor will gradually build up some gas and needs to be degassed (the pump may blow in some air, but also basic physics processes desorbing gases from the water having the same effect). A simple degas valve could have addressed all this, easy for initial setup and perhaps a weekly quick degas of the reactor.
How about noise? We see in the video, timestamp 8:30 that a gas pocket forms in the top of the reactor, where water splashes on the rotor. Go to timestamp 9:35, or review several other Youtube videos to learn that the reactor does not make excessive noise, but is not silent either. The point is however, that reactors that have no rotors and simply inject CO2 in the water column can be made perfectly silent.
How about the rotation of the water column? True, when observing CO2 bubbles spiraling down through the reactor it looks like the dwell time of each bubble seems to be longer than in a water column that is not rotating. But our intuition here is misleading. The vertical component of the bubbles motion is unaffected by the horizontal components, and indeed the rotation (movement in horizontal plane) does not increase the dwell time. The correct way, perhaps counterintuitively, to see it is that the dwell time is almost entirely dependent on the vertical component of the motion of the water column and the rotation is just an optical illusion in this regard.
So how about loss of flow from the pump/cannister? All reactors with bubbles in a vertical flow will create a back pressure and reduction of flow from the pump. This can be easily understood from the principle of an air lift pump, but unfortunately the pumping action from the bubbles works against our pump powering the cannister and reactor. The Sera reactor makes matters worse, as the energy from our pump is now also dissipated by the action of the rotors and the rotating water column. How much losses are caused by the rotor and water column rotation is difficult to say, but the point is that it is unnecessary to start with as the rotation does not add value compared to a much simpler Rex Grigg reactor.
How about maintenance? The Sera reactor is more complex than a simple functional Rex Grigg reactor, with more parts and unlike other reactors it has moving parts. The manual says “The rotors (6.3 and 6.4) may wear out after having been in operation for a longer time, also the O-ring seal (6.2) should be replaced after having the unit disassembled several times. These parts are available as spare parts” (end quote).
Our hobby is not entirely rational, and the marketing that Sera does claiming “The new sera flore CO2 active reactors 500 and 1000 with twin rotor supersede the generation of static CO2 reactors” may work for them. Whether it is a meaningful innovation from a functional perspective, or pricing perspective is a different question and all of the above is of course just my personal analysis and opinion and I do respect different perspectives.
Finally, a hint to the Sera R&D team (Reactor dimension can be calculated from tanks dimensions and CO2 ppm target, no noise, no bubbles, no flow reduction, no moving parts, compact and affordable)
I have a wonderful stand of erio feather duster that has been algae free for well over a year.
Wnen I firts got it, tufts of bba would form on it on tips and I would just pull them off…
This summer my display tank has been struggling with simmering algae issues.
Still doing weekly 2/3 water changes, keeping nutrient levels and all stable, trimming away degraded leaves…
My erio is in sad shape…
I have tried spraying peroxide on it when doing water changes, laying the mass on a cafeteria tray and spraying on full strength and letting it set for 10 minutes before refilling to no avail.
I gave the fikters a thorough cleaning out, andremoved and reset plant groupings after thoroughly gravel vaccing the bdbs to remove organics…
Iam starting to think giving the erio a good hair cut way down low and letting it send up all new leaves.
Figure I would poll the audience before taking any such action…
THIS SATURDAY! October 3rd Green Acres Center 10:00am - 5:00pm
pvas.com
Twice a year PVAS holds an All-Day Auction & Tag Sale: Auctions are free and open to the public.
Registration opens at 9:30 am, Tag Sale opens at 10:00 am, and auction bidding begins at 10:30 am. Sometimes there is a short break for lunch. Raffles usually occur about 1:00 pm and 3:00 pm. Bidding usually wraps up about 4:00 pm but continues until everything is sold.
@Sb1415 Apologies I totally snagged the format of your journal post for this so thank you!
Many moons ago I was an active and contributing member on plantedtank.net, I think at one point I had around 14 scaped tanks going before burnout and life changes. Instead of weekends consisting of maintenance I transitioned to camping/boating and life has been great. I’ve always missed it. After downsizing and making a move to a new home I kept only a small 12x12 cube tank that started life as an amateur iwagumi layout, Seiryu and hairgrass only. I put it on the nightstand beside my bed and added some of my favorite Anubias and crypts from taken down tanks. Its been sitting there running for 5-6 years now, low light, top offs only w tap. Maintenance when it got out of control. Super old aquasoil now flattened out to a thick 4-5 inch thick layer in a perfect line front to back.
In Aug/Sept 25 had a bit of a health issue that kept me in bed for several weeks recovering while I looked at this sad little cube, mostly healthy but not truly thriving. No fertilizer being added for years, GDA covered anubias leaves that also were many years old and I thought to myself I should make this better… that was the tipping point. OK I’ll do a deep clean on the substrate, get some stems to throw in there, maybe get a carpet going. Tissue cultures/stems ordered and I got to work. No more top offs, 10% water changes instead. TDS ~900 when I started. Ultimately everything melted back and didn’t grow well. I’d been keeping the lighting so dim all these years to maintain just the crypts/epiphytes without it turning into a mess and I was ok with it again. That was the spark.
I decided I wanted to build out a new tank, most of my old hardware/tanks I had let go of in a bulk way so I was going to have to start new with everything sans some 5 gallon buckets of Amazonia that I’d placed in the basement of the new house.. Phoenix rising from the ashes? Most likely more like algae emerging from the depths. I still consider myself a beginner and maybe amateur at best so yeah…
So I got to work again reading, researching, what’s new, what has changed since I’ve been out of the loop for so long? Ooo dark start that sounds much better, in line CO2 diffusers cool! CO2 reactors, pretty awesome sounding, 2Hr aquarist read every article, and I’m back in baby!
Tank inspiration
None really hence no name, it fit right into a slot to occupy my mind from a not so great situation that I was in and I’m ok with that. Ultimately I’d like this to be a low-mid energy tank that can have minimal amounts of weekly maintenance while still looking the part. I’d prefer to keep it as simple as possible while still having some high tech bits. Get all the equipment out of the tank, co2, low-mid level lighting, minimal/simple fertilization. I got busy ordering equipment and started brainstorming layouts and what hardscape materials I could find. Instagram was my friend for a while, seems that everything that kept grabbing my attention were island style layouts with a very thin layer of sand surrounding. I’ve also always been partial to big chonky pieces of driftwood, I thought to go the manzanita route but wysiwyg pieces were fetching stupid prices. I ran across this ironwood in a listing and couldn’t let it go. The deep lines in the bark were just calling me so I quick snap ordered it before my brain could process dimensions, I knew it would fit but didn’t fully visualise how much it would ultimately limit the layout. I wanted to stay mostly inert with stone and eventually/begrudgingly ordered the tumbled lava stone with the intention of keeping it to a island/river layout style and mimicking some of my found instagram muse tanks. It will mostly likely end up more nature style although the start will be more Willy Wonka than anything. Thanks @Burr740 for that, I shopped like a kid in a candy store.
Equipment
Tank
UNS 90L
90 cm x 30 cm x 30 cm
79 liters or 21 gallons by volume, 62.5 liters or 16.5 gallons actual w hardscape
Filter
Oase Thermo 200
Replaced the charcoal media with more ceramic from Oase
Replaced w Fzone stainless steel -Fzone glass Lily w skimmer ⅝”
Replaced tubing with UNS pro tubing ⅝”
Fzone Quick release ⅝” so Lily pipes can be cleaned without having to reprime filter
CO2
Gla inline atomizer - replaced Fzone Co2 inline diffuser ⅝”
GLA dual stage - replaced Fzone pro series dual stage regulator w/ 5lb tank
Timed on 3 hours before lights on, off 1 hour before lights off
Water
Using distilled by gallon, remineralized with salty shrimp GH targeting GH around 4-5
Hoping for 0-1 KH
Dark start cycled with prime dechlorinated Tap and APT Start
Substrate
80% old used ADA Amazonia v1, small bits sifted and bagged to create slight slope
2HR Feast topped to around 2 inches
UNS Bora sand
UNS Kona pebbles
Lighting
Fzone Bright 90 - 90CM
Before hardscape made rough par map using photone with diffuser iPhone 15 Pro
At 100% top 404, mid 219, base 127 PAR
At 50% top 190, mid 110, base 62 PAR
Will be starting tank with 45-50% lighting intensity
Timed at 3pm-9pm photoperiod with 60 minute ramps
Current Colorcast LED strip w/frosted background
Timed scenes for dawn (orange 1 HR during pre-ramp) /daylight (green during ON cycle) /sunset (red 1 HR during post-ramp) /night (indigo 1 HR after lights out)
Hardscape
Arizona Ironwood
Black tumbled lava stone
Ferts
APT 1 and 3 dosed at recommended levels per calculator
APT Jazz - in 3-4 months as Feast gives out
Trying to keep it simple with fertilization to start
Current status, ending dark start, overcast next few days so removed the cardboard surround last night. Took today off work and anxiously awaiting a fed ex delivery with a big box o plants. Here it is in “night” scene mode.
Well I’m done talking about it, it’s time to get this journal started.
I have been really out of it the last year or so in terms of maintaining my own tank, mainly out of frustration with time constraints and inconsistency with dosing etc. However, I have now acquired a dream tank, rimless and with low iron glass like I’ve always wanted. While I loved having a sump and prided myself on putting it together, I’m past that desire. The AIO allows the same benefits with hiding equipment, and overall easier maintenance without climbing in and out of cabinets. Now onto the details of this build.
Filtration: (2) 250gph pumps on either side of the tank with center overflow into socks (I’m going to punch holes in the socks for now and stuff with polyfill, reviews state the socks clog way too quickly and there is no replacement sock as the insert is not the common round style). The baffles will be stuffed with the poret foam I have already from my sump for extra mechanical/biological.
Substrate: The bottom layer will comprise of bagged pond soil/peat/earthworm castings/ STS. This will be a thin layer and will mainly act as filler to raise up the cap of APT Feast. This is similar to a substrate setup I did when I first started back up in 2020, And that tank did very well. While capping with sand and relying on the dirt to feed the stems worked well, it did require a little more effort on my end with dosing. I don’t trust myself to be as diligent as some members on here are with their inert subs, so I’m taking the mulligan and using aquasoil as a cap, hence, “dirty soil.” This will be another island style layout, and the surrounding substrate will be comprised of Caribsea Carolina Creek Sand.
Hardscape: River rock (local hardscape center sourced) and malaysian driftwood. I have recently acquired another large piece of wood and I’m sourcing new stone this week, as what I have just isn’t meshing with my current vision for the tank.
Plants: …. I have not solidified my vision of what this scape will look like just yet as I haven’t been able to setup the hardscape to outline the island. The plan is to use a good amount of colorful stems, epiphytes, and potentially moss.
Lighting: I will be ordering the Week Aqua Z400 this week and am excited to test it out.
That’s all for now, more pictures and details to come. I should hopefully have the hardscape setup by the end of this coming week after acquiring more stone and wood.
CO2: Almost forgot, for Co2 injection I have made a DIY Yugang with a locking food storage container. It will be stored in the cabinet and the hook will feed into the return pump chamber on the right. I initially was bummed that I had to sacrifice storage to fit a 5lb CO2 tank under the stand, which also meant getting rid of of the 20lb tank I’ve only been having to fill twice a year. @GreggZ Will appreciate this, my awesome father in law suggested that I hide the co2 tank in the pantry closet which is directly behind that wall and just drill a hole for the co2 line. Since my father in laws word is pure gold in my wife’s eyes, that suggestion was approved! He’s just as much my dad too so I appreciated him supporting the project
I hadn't seen it mentioned by others that attended Aquashella, but if you hadn't already heard about it or seen it in Aquashella videos, ADA has come out with Amazonia Pro. It's not a replacement for Version 2, but an addition. It is essentially Version 2 on steroids with higher nutrients and of course the negative side effect of potentially higher initial ammonia leaching and, if your not prepared and skilled, more chance of algae. That's even from the mouth of Homma-san himself. The scaping competitors were using it in the competition and AFA was selling 9l bags at the show. They said it would be available on the website within the next couple weeks.
So they have been around for ages and there is no doubt that they do work. I have a hang on one that I will bring out if I ever get a green water outbreak, ich or other issue that I think it can solve. I think many of us have one in our "aquarium stuff" pile.
The question is, should we run them continuously? There is a school of thought out there that thinks this impacts our fertilizers so they shouldn't be used continuously. Any thoughts on this?
How about if you're keeping sensitive fish like our friend @BryceM? Discus are real sensitive to bacteria. Would you run a sterilizer 24/7?
Would love to get your thoughts on this?
P.S., these questions of the day are intended to get us talking to each other. If you see this, please give your 2 cents even if it is "I have no idea". Our community will be better for it.
Well...let's spend more money! I had thought about attending Aquashella - Chicago a few months ago but decided to pass this year. When I was thinking about it, they still didn't have the specific VIP guest list posted. Out of curiosity, I checked today and to my surprise, the man himself, Yusuke Homma, will be presenting the masterclass on Saturday. I can't pass that up when it's only an 8 hour drive. Ticket purchased, room booked. Anyone else attending?
Browsed the Sreepadma booth at Aquashella briefly today. I'd not heard of them but they are the largest aquatic plant farm in India and have been selling their TC offerings in the US for about 2 years. I was actually impressed with the qualty I was seeing of their TC cups and wish I had room in a tank for some (and some ADA TC). Has anyone else purchased any of their plants. One of the first that I spotted was Red Tiger Crypt which was a coincidence since we have a thread discussing it.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.