# Does an overdose of Excel kill inverts?



## DJKronik57 (Apr 17, 2006)

I'm suspicious because I had a mass die off of cherry shrimp a little while ago after dosing more than the recommended amount of Excel, and now I'm dosing 4x every other day to combat algae and my once thriving snail population has seemingly almost disappeared. Baby rams horn snails used to cover the walls and the plants, but now I only see a small handful, and dead snail shells litter the substrate. It could just be a coincidence, but it's a little too coincidental for me.

Has anyone overdosed Excel over long periods of time (4-5 days or more) in a tank with inverts and _not_ lost any? I know snails are hard to tell, since often we don't miss them when they're gone, but what about shrimp?

If it does kill inverts, it would be a mixed blessing. It would be a safe snail removal or suppression tool, but it would also mean limiting its use in shrimp tanks. Just wondering what other people's experiences have been.


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## erijnal (Apr 5, 2006)

Interesting post in the Algae section on the "Flourish excel got rid of all my algae" thread



> Hypothesis: Excel kills algae at low ppm, inhibits (kills) bacteria at higher ppm (perhaps at levels 2x3 times used as doses by most members)
> 
> dead algae + reduced bacteria = altered nitrogen cycle in tank. In this logic, we may also experience an increase in ammonia + nitrites as a result of decomposing bacteria and lack of nitrifying bacteria to process waste.
> 
> ...


Of course it is only a hypothesis, but it seems very valid to me and may explain the cherry shrimp/snail die-off.


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## DJKronik57 (Apr 17, 2006)

That makes sense, except an easy way to test it is to test for nitrites, and my tank is showing up with 0ppm. Nitrates are at 20ppm. In order for that hypothesis to be true, there would have to be some nitrites in the tank, right?


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## chiahead (Dec 18, 2004)

Yes, I have killed many a shrimp and snail due to an excel overdose. It has happened on multiple attempts so I can only attribute it to the excel.


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## Cassie (May 27, 2006)

I'm guessing my cherry die off was also due to an overdosing of excel. They'd kind of twitch and die, and there was nothing you could do. I did a massive water change, even moved some to another tank and I lost most of my cherries. I didn't notice any effect on snails, but I wasn't really paying attention eiter.


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## erijnal (Apr 5, 2006)

I know nitrite and ammonia are closely tied, but did you test for any ammonia anyway?


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## aloha (Jun 2, 2005)

I can't tell about cherries but in my case the 4X excel daily dosing for 2 weeks didn't hurt my amano shrimps.


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## chiahead (Dec 18, 2004)

Ya my amano shrimp made it fine too. I think they are really hardy for a shrimp. I mainly lost cherries.


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## milalic (Aug 26, 2005)

It will kill cherries and other shrimp. The only ones I have seen surviving it are the amano shrimp.

-Pedro


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## acedia (Dec 23, 2005)

i had the same thing happen i figured i added my shrimp too soon, but it was only my charries that died also my amano and ghost shrimp were still kicking after 9 of 10 cherries died within 3 days


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## Gomer (Feb 2, 2004)

*I have overdosed Excel NUMEROUS times*

Usually, it is 2x but a couple of times, I have triple dosed. I haven't seen a single fish or cherry shrimp casualty in all my overdosing experiences.

YMMV


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## dhavoc (Mar 17, 2006)

same here and i do a 3x od, but only for 3 days in row max. then massive water change. and this is my CRS tank. just did it a few weeks ago to eliminate an out of control staghorn, hair and string algae problem. all came thru with not even an indication of stress or anything. worked with my wild cherry tank also, and that tank has hundreds of them in there. i wish it would affect snail but alas not a twitch from them.


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## AndyT. (Jun 28, 2006)

Have any of the folks who have had problems asked Seachem about this? Maybe they will have some insight. I have found them to generally be responsive to consumer inquiries.


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## chiahead (Dec 18, 2004)

AndyT, they may not comment on this because the directions for the Excel say specifically not to overdose the product. I dont think they would put that on there unless there was a danger or possible danger of something.


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## Cassie (May 27, 2006)

I was only double dosing, not anything more. I wonder if, since my cherries had been in the tank for less than a month (the tank was established before that) that they were still possibly stressed, and then weaker because of that? Or maybe there are strains that are weaker than others because it's seeming that either a majority were effected, or none were effected...


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## DJKronik57 (Apr 17, 2006)

It could be another factor as well, such as something else in the water, the water parameters themselves, or any number of variables combined with the Excel overdose. I have Amano shrimp as well and can say that they seem to be resistant to it. Cherries seem to be the most vulnerable for some reason. We may never know since everyone's water is different and everyone adds different things to their tanks, but I think it's safe to say that Excel is the common denominator.


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## argblarg (Aug 10, 2006)

I did 2.5x for 14 days and had no cherry shrimp fatalities.


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## Ibn (Oct 20, 2004)

I dose 1mL to about 1.5 gallons of water. I'm sure that's at OD levels, but haven't had any problems yet.


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## Cassie (May 27, 2006)

I wonder if pH may be a factor. It'd be interesting to see, so you can post if you had problems or not, and then your pH. 

I had problems and my pH in that tank is 8-8.2


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## DJKronik57 (Apr 17, 2006)

pH 7.0-7.2 for my tank


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## erijnal (Apr 5, 2006)

According to SeaChem, Excel will not affect pH.



> Q: Is it better to add Flourish Excel at night or in the morning based upon plant carbon uptake physiology?
> A: Carbon intake is a function of photosynthesis. Based on this, it would be ideal to dose Flourish Excel during the day. But given that Flourish Excel can stay complexed as a carbon source for up to 24 hours before it dissipates, you can dose at any time of the day and the product will be available for the next 24 hours. *Flourish Excel is not carbon dioxide and there is no impact on pH using Flourish Excel*.


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## DJKronik57 (Apr 17, 2006)

I think the suggestion was that maybe depending on your pH in your tank, Excel can become toxic to inverts in high doses, not that it affects your pH. For example, someone with a low pH might overdose all they want and have no affects, but someone with a high pH might wipe out all of their inverts.

Just brainstorming reasons why it may be toxic in some tanks and not in others. What about temperature? My tank is always around 80F. Maybe in warmer tanks it becomes more toxic?

Whatever it does, it seems to affect their nervous systems because they act all funny and die twitching.


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## Cassie (May 27, 2006)

DJKronik57 said:


> I think the suggestion was that maybe depending on your pH in your tank, Excel can become toxic to inverts in high doses, not that it affects your pH. For example, someone with a low pH might overdose all they want and have no affects, but someone with a high pH might wipe out all of their inverts.


that's exactly what I was going for, factors that may effect the toxicity of excel.


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## Zoombob (Mar 13, 2013)

Hi - new here, so I don't know if it's bad form to post to a six-year old thread. I have a 10 gallon planted tank with EcoComplete, just started the Walstad method about four months ago. Plants weren't growing very quickly, so reading about Flourish Excel here I gave it a try yesterday. My "assassin" snail immediately headed for the exit when I dumped in the initial 5ml dose (that's a 5x normal dose for a 10 gal tank). Today I added 1ml, as directed. The snail is now above the water line, and it looks like he's not long for this world. 

He's been a useful creature, breaking down the fish food and so forth. He was growing nicely, a happy little guy. I feel bad that this is happening, but I had no idea he'd find it toxic. I have 6 flame tetras and three cories who are all doing just fine. I hesitate to do a water change, since I'm going El Naturel and want to see the Excel do it's magic. 

Any thoughts?


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## TarantulaGuy (Apr 15, 2009)

Excel can most certainly be toxic to inverts. I've nuked quite a few shrimp with it before on accident. In smaller doses they seem to tolerate it, but it certainly isn't good for them.


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## Zoombob (Mar 13, 2013)

I wish I'd known that beforehand! As it turns out, the assassin is back on the prowl, after a water change (20%) and no more Excel. He hung out for a day or so above the waterline, and decided it was okay to go back into the pool. I will be very sparing with the Excel from now on.


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## TarantulaGuy (Apr 15, 2009)

Generally on a thread this old, it's a better idea to simply start your own. But since it's here. If you're wanting to see a little faster growth, I'd recommend DIY CO2 instead of excel if you are concerned for inverts. It's safer, and in the end much cheaper.


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## Zoombob (Mar 13, 2013)

TG - thanks for the protocol info. Will do, next time. 
As for plant growth, I think I will stick with the Walstad "fish food as fertilizer" method. I've also added more plants, so the tank is now moderately planted. I added a long water sprite that is spreading along the top, getting CO2, as she suggests.


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## TarantulaGuy (Apr 15, 2009)

Sounds good. As a personal thought, try not to get too caught up in any one "method." While what Walstad does works for her and for a good many people (I do have her book, even though I don't follow it strictly speaking) do what works for you, don't be afraid to reach into other "methods." If you want a little faster growth than what you'll get from a straight el natural tank, don't be afraid to venture out a little. I have a little 10 gallon tank that is well established, gets no fertilizers, has a relatively heavy fish load, so by all accounts is mostly "natural" except that I blast it with lots of light. I get better growth, and still no algae. Half the fun (for me at least) in this hobby is experimentation and finding what works best for you, and not religiously following someone else's system.


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## Zoombob (Mar 13, 2013)

That's good advice, TG! Having fun with it (and success) is what it's all about. Fishies are looking happy this morning, Rover is back to his roving...life is good. Sunshine in Pittsburgh on a Saturday!!


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