Updating Our Spec V with Pressurized CO2

We have made some dramatic changes to our little Fluval Spec V aquarium over the past month.  All summer, I got more and more tired of trying to wrangle the Cryptocoryne Undulata plants.  They became very invasive and I didn’t do a good job of keeping them in check.  At some point it seemed the best solution was a whole tank rescape.  It had been two years since the last rescape, so it was a good time to do it again.

fluval spec v aquarium overgrown with low light cryptocoryne undulata plants

The substrate gets a little tired over a 2 year period, and was full of detritus, so I wanted to swap that out entirely.  I got a nice surprise with the new order of Up Aqua AquaSand – the product is much darker than what I purchased two years ago.  I know it is darker because I kept some of the previous bag separate and I could compare the two as new.  It looks much better darker!

Anytime you tear down a tank you start to think about making change upon change.  First of all, I am tired of dealing with driftwood.  It looks very nice when new, but the wood I have used tends to degrade and melt over time.  I though it was time to get some rocks instead.  I chose Ohko stone sourced from a seller on Ebay.

closeup of ohko aquarium stones

Beyond that, I have thought that one way or another, CO2 would sure be nifty to get going.  I know that our algae issues are entirely because of the low CO2 (with our current light intensity).  My thought process was first and foremost to get CO2 going to help reduce algae, no matter what plants we use.  DIY CO2 crossed my mind and I did some research on that.  However, It seemed DIY CO2 (using fermenting chambers) is not right for us.  Too much work, too many inconsistencies.

Then came the big leap – a decision to source and assemble a paintball CO2 system.  Going pressurized seemed like the best long term decision for us. High initial cost, but better in the long term and a solution that ultimately meets all our needs.

assembled parts for planted aquarium paintball co2 system

Getting the CO2 system going took lots of research, learning, and first-time blunders, but overall, I’m surprised how easy it all came together.  I actually got the pressurized CO2 system going with the old setup for a week to dial it in and get the drop checker turned green (getting in the ballpark of the right flow for CO2).

Often times, decisions become like an avalanche that you can’t stop.  Predictably, once I got the pressurized CO2 system installed, I had everything in place to basically be running a high-tech aquarium.  Suddenly, the low/medium light plants I have been raising for three years didn’t seem all that attractive to me.  Yup, I put in orders from various eBay vendors to get some new plants.  A sprig of Blyxa Japonica, a few bundles of rotala green, some staurogyne repens, and a cute little pot of HC (dwarf baby tears) to try as a real carpet.

tissue culture Hemianthus Callitrichoides 'Cuba' or dwarf baby tears

I then tore down the entire tank for an official rescape.  Everything came out. My sweet wife took on helping me arrange some of the stones.  The plants all arrived in the middle of the week.  I hated to leave the plants in their packages one more day, so I ended up putting the substrate in and planting that night.  I stayed up till 1:00 am planting that HC carpet! Hard, but so much fun!  A few days later, I felt good enough about the tank operation to move the fish/shrimp out of the quarantine tank and back into their home.

high tech planted spec v aquarium

We promptly left the next week for a week long vacation.  Not the best timing. Everything (lights, CO2, fish feeder) was on a timer.  I had a friend come over mid week to add top-off water.  I double dosed the daily EI quantities before leaving to try and tide over the nutrients.  I really thought the tank would be a wreck and ruined when we got back.

I was stunned on the tank’s progress when we got back home.  The rotala was transitioning from emersed growth to immersed growth and had bulked up substantially.  The Blyxa Japonica was changing color.  Finally, the Hemianthus Callitrichoides (HC) carpet was taking off!  Only one week and I could see substantial growth – it was truly filling in.

growth progress of Hemianthus Callitrichoides 'Cuba'

We are now over a month into this endeavor and I am thrilled with our change to pressurized CO2.  I very much enjoy the new plants more than the old – they are beautiful.  I enjoy the faster growth – every day the tank changes.  The pearling is fun and beautiful.

There will be many pages that are born from this effort.  I hope to pass along what I have learned:

  • CO2 Equipment Setup: It really isn’t that hard to get it all together.  The cost wasn’t as bad as I thought either.  I will write a page on what regulator I went with, the ins and outs of purchasing a tank, and how to diffuse CO2 into your water.
  • CO2 Adjustment:  I have learned a lot about how to adjust the CO2 rate injected into the tank.  Much of what people suggest on the internet forms is not necessarily the best.  I have found some techniques for setting the bubble rate that have worked out very well.
  • Fertilizer Dosing: I am using the very same dry fertilizers, dosed directly into the tank, that I used before on the low-light setup.  The only difference is that I now dose daily instead of weekly.  It is not hard at all.
  • Lighting:  I’m using the same Finnex Planted+ light that I have used since we first got the tank setup. Seeing the rate of growth with pressurized CO2 added makes me realize this light is much more powerful than I knew.  It is definitely in the upper range of medium light. EDIT: Since writing this, I have switched to the Finnex Planted+ 24/7 HLC.  This fixture is brighter but also allows custom adjustment to tailor the light color and intensity as you need to.
  • Algae:  It is mostly controlled.  The only struggle at this point is some green spot algae on a few leaves and especially on the glass.

I will also try to get some better full tank shots as the months go by to document the progress.

nano aquairum with high light plants

18 thoughts on “Updating Our Spec V with Pressurized CO2

  1. Roughly how much did the CO2 system cost? How much work is it to make and maintain? Can you link/make an article about it?

    1. I will make articles about the setup of the system shortly. If you pick decent components, maintenance is very low (almost set and forget).

  2. Thank you for your very informative site and articles. Just got my Spec V today – it appears Fluval has made some changes. The light is all aluminum with no droop, the output hose is black, the slot between the sump section and filter media is wider, and the filter section isn’t frosted, it’s a printed black screen mesh. Have you seen this new tank?

    1. Well, I’ll revise my statement, the light isn’t AS droopy. It’s still floppy and I also noticed the night LEDs stay on with daylight ones too. I’d like to upgrade the light too, just initially struggling with the idea of the light being as expensive as the whole tank!

      1. Yes – it is hard. I’ve spent many times over on accessories. In the end, the extra stuff has gotten the tank where I want it, so it ends up being worth it.

  3. Nate, you’re a brave man. Really very nice looking aquascape. I haven’t been bitten by the high-tech bug yet, but if and when I do, I know just where to go to get great information.

  4. Excellent information on people that would like to step into the high tech game but aren’t sure as there’s many possibilities and expenses that add in. I might actually look into this if I I change my smaller tank into a mini high tech world. Thank you for your blog information! 🙂

  5. Did you ever end up posting the details around your Co2 system? Would love them.

    1. still working on those posts. will start with a post on the hardware, upcoming.

    1. You bet. Been busy but hoping to post more about our CO2 system in the near future.

  6. Hope to see the c02 update. Curious how you went about it.

  7. Hi Nate,

    Question for you about the water flow of your tank post CO2 install. I like many other readers modified the tube to circulate water around the heater and because I have a beta fish. I have noticed that the nozzle must be pointed correctly to help circulate water. I am using Estimated Index as I think you are. Given that I have pretty much done what you have with CO2, Inkbird, tube mod and light I am curious if you have seen any flow issues? Have you observed any algae or plant issues as a result of the flow pattern?

    In my case using EI, and CO2 I think I have everything dialed in but am seeing some holes and yellowing on leaves. Since I am learning with easy plants I want to make sure I correct and learn from any issues before moving on to more demanding plants. Rather then assume nutrient deficiency I am starting to look at flow. Over at Barr Report they will always ask to double check CO2 and good circulation before addressing any deficiency. I just ordered a new flow tube and will very carefully add holes this time.

    I also want to thank you for all the time you put into this site. I have basically used this as a guide to setting up my whole tank, stocking it, upgrading lighting and adding temp/lighting controllers and now adding CO2. Thank you for sharing your experiences and knowledge!


    1. Since introducing CO2 and moving to high tech, I have tried to increase flow from the nozzle. I did this by putting silicone over 2 of the three holes I had drilled in the tube. The pump is turned all the way up.

      My tank is doing well. I do have algae (green) that grows on the glass and rocks. That’s about it. I have noticed some signs of deficiency in the past month (slowed growth especially for one plant in particular) and I think it has to do with my substrate loosing some nutrients. I have started to also dose potassium phosphate every other day and it seems to help.

      It’s good to look at flow; however, in a tank this small it should be easy to get enough flow and get the CO2 delivered throughout.

      1. Hi Nate,
        Good to know, thank you. I have potassium phosphate on the way as well as a new flow tube. That should do the trick. I have some huge holes in the tube so I will be more more precise this time.

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