Excel dosing, a middle ground for aquatic horticulture methods

Tom Barr

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Bridging the gap between the methods and each of their perspective trade offs is a challenge for many aquarist. There has been some confusion surrounding the use of Excel, a product made by Seachem Laboratories and which method to use for this.The first real issue in the trade off is to understand that Excel will radically increase the rate of plant growth. Not like CO2 by any means, but a lot more than a traditional non CO2 approach. This means that adding supplemental fertilizers might be required, particularly with light fish loads/feedings.

The biggest advantage to using Excel is really allowing the aquarists to use water changes versus a traditional non CO2 approach which discourages water changes.
This may be done weekly, once every 2 weeks, or monthly at 50% or 25% etc. you may also use test kits to determine when a good water change is required based on NO3 build up. Often times, aquarists want to not hassle with as much gardening, nor deal with CO2 systems and higher light, nor frequent water changes, but not go so far as to avoid them altogether.

This allows aquarist to keep higher fish loads, less pruning and algae, fewer water changes, but still have a nice looking aquarium with a wider range of aquatic plant species. Negative Trade Offs: Excel is toxic at higher than recommended label rates. Some get over zealous and kill their shrimp and fish. Cost: it can become costly over time and with larger aquariums. Needs dosed often, not a big issue if you add fish food often as well, dose the Excel when you add food etc. More pruning requirements, this might be good and bad depending on who you ask.

I do not think using Excel should be viewed as non CO2 methods, it has more in common with traditional CO2 enrichment methods, so those methods are more applicable overall. While not a gas when you add it, it does turn into fixed carbon, so the aquarist is enriching their tank with carbon fertilizer. I think there is about a 250-300% increase in growth using Excel compared to non CO2. There is about 1000-2500% increase in rates of growth using CO2 gas. So Excel is about 1/3 or thereabouts that of CO2 dosing. So the nutrients can be adjusted relative to that for CO2 vs Excel dosing. Note, using sediment enriched sediments like ADA' s aqua soil are beneficial with Excel and allow water changes for the first few months/weeks. Then very little dosing is required other than perhaps some traces, feeding fish etc. Many CO2 gas aquarist want this type of dosing routine, but often have more trouble using CO2 gas and complaining about pruning, algae and other issues. This method can help, but also, this is true for all methods, using less light will reduce the amount of work, maintenance and rates of growth, making the aquarium easier to care for and less prone to algae.

Using Excel is no different. Many try to use Excel as an easy way around having to use CO2 gas and then make a really bad assumption: more light is better.
Both CO2 gas and Excel do exceptionally well with relatively low light, say 1.5-2 w/gal using T5 light is plenty to grow any species in typical shaped aquariums.
Still, using Excel, aquarist should stay at 2w/gal or less for their lighting. Some get away with more light, but as you add more and more light, you increase risk of algae and plant health issues. Stick with the middle ground lighting or error on the lower side, plants will still grow and be easier to manage, which is often why everyone dose not use high light/CO2 :p

You may not have the goal to grow aquatic plants as fast as possible.
So control the rates with CO2, non CO2 or Excel and mostly with light.

Regards,
Tom Barr
 

guy tillmans

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Jul 29, 2008
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Is it usefull by moderate lighting(1.5-2 wpg) to use excel AND co2 together?? Can cause to much carbon icw moderate light , algae? Or in anyway ,can to much co2 cause algae?? (probarbly a dumb question, but i want to be sure about that)
 

Crazymidwesterner

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My excel experience was terrific. Little to no algae, great plant growth and the cost was below that of pressurized CO2 unless I look out to like 10 years of use. The only down side is it did limit the plants I got to use a little. Certain plants definately reacted to it better than others. I went with Pressurized thinking I would get better growth results but so far I have only had a lot of issues. Once I get it dialed in I'm sure it will be great but excel for me at least was an easier option.
 

Tom Barr

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guy tillmans;29761 said:
Is it usefull by moderate lighting(1.5-2 wpg) to use excel AND co2 together?? Can cause to much carbon icw moderate light , algae? Or in anyway ,can to much co2 cause algae?? (probarbly a dumb question, but i want to be sure about that)

They can and do work in conjunction together.
But there's little point if you have CO2.

Learn to use the CO2.
You will not get more algae etc form adding too much CO2, the algae are not CO2 limited.

You can get algae from varying the CO2 from high to limiting levels for the plants.

That's really an issue of stable CO2, as the lights come on, the plants start removing it, your system and method has to have a way to add what is removed by the plants and maintain a good residual ppm of CO2.

Problem is, many folks cannot do that well.
So they get algae and have semi good plant growth, but focus entirely on algae and thinking they just need to get rid of that to solve all their problems.

This is not the case nor how to go about it.
Use the CO2 correctly.
Use less light since it drives CO2 uptake and less light= less CO2 demand= less algae growth also. Less light makes balancing the amount of CO2 added to the system easier than high light.

Regards,
Tom Barr
 

Crazymidwesterner

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AdlA;29765 said:
Which plants do poorly in excel? Which plants do well?

I can tell you that vals do not do well. These reacted the worst. Other plants that didn't flourish for me were HC, dwarf saggitaria, rotala rotundifolia. I can't completely blame the excel as I have done zero experimentation but I have had more success with all of the above using CO2.

Plants that did well for me are Ozelot swords, baby tears, Moneywort, pennywort, Ludwigia repens, ambulia, anubias, several crypts, java moss I can't remember everything I've tried.

Oddly my java fern never did well until I switched to CO2. I doubt it was the excel but just an observation.
 

Tom Barr

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As far as I can tell, a few species do not do well, mostly Hydrilla, Elodea, Egeria densa etc, likely Lagaorsiphon.

Several have said Vals, I have cork screw vals and have not noted any issues.
Same with mosses. Some liverworts might take a beating, Riccia seems pretty tolerant. I know HC does well using Excel as do most typical stem plants.


Regards,
Tom Barr
 

Henry Hatch

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Aug 31, 2006
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I currently have 3 excel tanks running. Excel seems to work quite well with plants which do well in lower light. These tend to be broader leafed plants. I've had less success with stem plants although some like rotala indica seem to do well. In lower light co2 seems to really help stem plants. Vals do not do well even at recommended dosage. I called Seachem about Vals and they did say they have had people comment about problems.

Dosed at recommended levels I think excel is quite economical. I do 25% water changes a week. Water changes greater than 40% require dosing at 5x the normal rate so that will drive up costs. Once in a while I do a 70% water change just to purge any excess fertilizer build up.

I have been moving in the direction of lower light recently. In my small tanks I like to plant stem plants since many of the lower light plants grow quite large and can take over a small tank quickly. However, I really think many stem plants need the co2.

Henry