Seachem Excel vs CO2 Dilemma ???

  • #1
HI All,

I have a 12.5G planted tank running from last 6 months or so. I use Tetra Florapride on a weekly basis (after 50% water change) to fertilize.

Recently about 1.5 months back, I added 5 Amano Shrimps but out of the fear factor of PH swings, I disconnected my DIY CO2 system (running on a heavy diffuser - one with 3 bio balls). Unfortunately, I use the API 5in1 test kit and always the PH reflected by them was around 6.5. My CO2 calculations always have shown me a very high CO2 content. So with Amano Shrimps in the tank....I decided to switch off the CO2 system to be on the safer side.

Now, my plants are showing a lack of growth vis-a-viz when I used CO2. It seems like the plants are not dying, but are not growing as well either. To counter this problem, I have started dosing Seachem Excel since last 1.5 weeks, but still seems of no help. (Pics enclosed)

Do you suggest me to wait further to see results from Seachem Excel OR should I start the DIY CO2 system again ?? Pls share your experiences with Seachem Excel.

Thanks in Advance. (I am sure Nutter would be there to support me always.)


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Nate McFin
  • #2
Here is my take, others opinions will vary. I would go back to DIY Co2. Excel is a source of carbon for plants but its main ingredient is also a hospital sterilizer. (Do a search for gluteraldehyde and see what fun reading you find!)
The Ph changes from Co2 in my opinion are not a problem. Your fish will die from Co2 poisoning long before the Ph swing gets them. Here is a link for you to check out...

So...Hospital sterilizer or Co2....I would take Co2 and keep the excel for spot treating algae if it ever pops up.
EDIT- By the way forget your Co2 calculators...they don't work. If you want to measure Co2 use a drop checker with a 4dkh reference solution. It isn't perfect but its as close as you will get and much more accurate than charts you find on the net.
More info on drop checkers...

Now I will run for cover....I can feel the rotten tomatoes coming...(Sorry Nutter!) ;D
  • #3
No tomatos Nate. I agree with everything you said except for the PH swings not being an issue. Even that depends on how big the swings are. I'm a big fan of having an airstone running when the lights are off to help keep the PH more stable. If the swings are less than 0.4 & the PH isn't dropping under 6.4 overnight though, there's not really much to worry about. I have lost fish from the PH swings before but the swings I was getting were closer to 0.8-1.0 drop overnight.
  • Thread Starter
  • #4
HI Nate & Nutter,

Many thanks for the valuable insights. So, finally the way forward is CO2 indeed to make plants "Flourish" !!

I do not have the budget for pressurized CO2 thus DIY CO2 is the only option for me. Both from Googling & my own experience, I am aware that maintaining the appropriate CO2 levels with DIY are hard to attain.

1. Any recommendations on how can I maintain the right CO2 levels (without killing my fish / shrimps) ?

2. Does reducing the number of BIO Balls in diffuser have an effect on CO2 levels ?

3. Should I run the diffuser 10 hrs (along with light) OR should I keep it running 24 hrs ?

4. I also use a additional air-pump powered filter (running 10 hrs/day with light). Would that reduce the CO2 content in water ?

5. Would you suggest me to switch from Diffuser to Air-stone which can keep running 24 hrs on DIY (without bothering for Diffuser switch on/off). I tried to use a airstone once but the bubbles made by it are too big thus resulting in in complete efficiency.

Many thanks. Look forward to your expert views.
  • #5
1: Usually the way to maintain stable co2 levels is to run a multiple generator set up. On a small tank such as your 12gal thoough that might put your fish at risk. You will be better off having two generators, but only having one hooked up at a time. Monitor the bubble production closely (you can make a bubble counter similar to a yeast generator). During the first couple of days, a yeast mix will have a high bubble production rate. After that, bubble production will drop & level out for a longer period, usually 2-4 weeks. After that period of steady production, bubble production will slow down until it eventually stops. Your aI'm would be to have the gerators hooked up to the tank during the longer period of steady bubble production. When you know one of the mixes is a few days away from needing replacement, make up a new mixture in your spare generator & give it a few days to start the reaction & for bubble production in the new mix to level off. Once it has levelled off, disconnect the old mix that is about to die & hook the new mix up.

2: Reducing the number of bio-balls in the diffuser will have an impact on how much co2 is diffused but that impact will probably be minimal depending on the exact design of the diffuser. Changing the type of diffuser altogether will have much more of an impact.

3 & 4: With diy co2 I believe it is best (& easiest) to leave the co2 running 24/7. Any surface disturbance will disipate co2 back into the atmosphere. The more surface disturbance the faster the co2 dissipates out of the water. For that reason I do not recommend having any air driven filters or stones running during the lights on period, unless they are needed to avoid overdosing co2. A small power filter will serve you better (& can act as a diffuser). Trying to minimise the surface disturbance during the lights on period will hold more co2 in the water. Increasing surface disturbance during the lights off period, will help reduce the co2 levels overnight & ensure a good supply of oxygen for fish & more stable PH levels over a 24hr period. I use air pumps set on timers to come on at night & increase surface disturbance that way. It's the easiest method I have come across & beats fiddling around with solenoids etc.

5: You can switch diffusers if you like but regular airstones make poor diffusers. There are special ceramic or wooden co2 diffusers but their performance also leaves a bit to be desired. I would probably stick with the diffuser you have now so long as it is driven by a power filter of some kind & run an airstone at night to keep the PH swings to a minimum & ensure adequate oxygen supply for your fish.
  • Thread Starter
  • #6
HI Nutter,

Many thanks for your words of wisdom. A small tank is bit hard to maintain, I wish I had bigger tank like yours.

I lost $8 on investing in Seachem Excel >. Let me switch back to DIY CO2 and try multiple permutation / combinations. I will reduce the Bio-Balls in diffuser from 3 to 1 and will try running it 24/7 on two generators as advised by you. I will post my results in some days.

BTW, is the drop checker reference solution is sold readily that I can buy from my LFS ?

Many thanks once again for your help x
  • #7
Sounds like a plan. Just remember to have only one of the co2 generators hooked up at a time. The other bottle is just so that you can change the mix without interupting the constant supply & so that you can always have a generator hooked up during it's longer level of steady production. Hooking up two yeast generators at once to your tank would probably be too much for your fish to handle.

You can buy drop checker solution but it's much cheaper to make your own up using Baking Soda & Distiled Water. You need a KH test kit to make it but you should really have one of those anyway when your using co2.
Nate McFin
  • #8
Keep your Excel. If you ever have alage it can be used to spot treat. I always have a bottle laying around just in case.
  • #9
I don't care if Seachem Excel main active ingredient has other uses. It has a quite safe history among fishkeepers. I use pressurized CO2 in 5 tanks and Flourish Excel in 4. As long as overdosage is avoided it's safe for most plants, inverts, and fish.

**** was made as a cardiovascular drug and ended up solving a major sexual health problem.

Household ammonia solution is another cleaning agent and I use it to cycle all my tanks.

Activated charcoal can be used as fuel but I use it in some of my tanks.

Peat fiber is used in land gardening but I use it safely to lower pH.

My pressurized CO2 is made for medical use but I use it safely as well.

Santo Domingo
  • Thread Starter
  • #10
HI Pepetj,

Even I am not bothered of what the "ingredients" are as far as

1. The product can work
2. It does not harm my flora & fauna

But the main issue is the product does not work (at least with my experience). Anyway, I have switched on the DIY CO2. Lets wait for 2 weeks when I post the results back. Then we can have comparative analysis of using Excel for 2 weeks vs 2 weeks with CO2.

BTW, it would be really nice if you can post your analysis of plant growth with Seachem Excel vs CO2 since I see you are using both of them in your tanks separately.

Nate McFin
  • #11
But the main issue is the product does not work (at least with my experience).

It didnt work well for me either. When I switched to DIY Co2 the difference was night and day. I was dosing ferts however and was fairly certain the only reason for lack of growth was Co2. Nothing else at least on paper was limiting the growth.

As far as being harmful, I was using Excel as described on the bottle. Over the course of 6 months using it I kept losing Cardinal Tetras. When I stopped using it the mysterious deaths stopped. I had read of some people who had problems as well but I wasn't sold on the idea then either. At one point I decided to give it another shot guess what....more Cardinal deaths. At that point I was done with losses since. There are some other reports of this out their.
Having said that, Excel seems to work for a lot of people, most may not see loss to fish. I still recommend it but I do like to thow the info out there that it is something that should be watched. Co2 can kill fish just as quickly.
  • Thread Starter
  • #12
HI All,

Its not even full 2 weeks of running CO2 again and as Nate has mentioned.... the difference is of "Day & Night" !!

Suddenly, plants are showing signs of showing growth. As you can see, the plant in the middle (with round leafs).... has suddenly grown its leaves big, some more new are comming. The plants at side have grown taller.

Fortunately, my Shrimps & fish are all okay (while Shrimps are really going big in size... ;D).

HI Nate.... the bottle of Excel is still with me... now to counter algae if it comes

Thanks Guys.....
Nate McFin
  • #13
Great to hear and thanks for the update! It is always nice to know the outcome of things.

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