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Discussion Starter · #1 ·
Hey guys

Last week I have been using glutaraldehde in place of excel.I'm using a 2.8% solution.It's suppose to be about the same as excel but alot cheaper.I paid $16.95 a gallon.

I tried it in two tanks,a 10 gal. planted and a 60gal. planted.
It had a different effect in each tank on some of the same plants.Below I'll list each tank with the dose and effect I noticed.


60gal.,192 watts,11hours lights on,co2 injected,ferts daily,plants are red tiger lotus,rotalia indica,sword,ludwigia,anubias,hair grass and crypts,34 fish.

I dosed 30ml 9/23/6 after a water change then 10ml daily.
On 9/25/6 the angelfish spawned so it seems to have no effect on the fish.
9/27/6 the sword plant started growing fast.3-4" growth of new leaves daily.this plant has not grown much in the last 3 weeks.

It's been a week so far,water is clear,plants are growing fast and the little bit of algae I had is gone.

riccia is ok.

Now for the 10gal.,30 watts 8-10 hours,no co2,ferts daily,plants are sword,red tiger lotus,ludwigia,and bolbitis,tiger barb fry,cherry shrimp and alot of hair algae.

I dosed this tank heavier to see what would happen.
5ml daily.
9/23/6 dosed at 10:00am and by 7:00pm algae shows signs of dying.fish and shrimp are fine.

9/24/6 riccia is dying off.All the algae dead.fish are fine.water is a little cloudy.

9/25/6 water is clear.I have a few strands of moss in this tank.I think it's java moss.It is growing very fast.

9/30/6 moss has grown around 10" this week.this moss has been in here for 8 months without much growth.The bolbitis is a little darker green and the leaves have widened.Looks healthier then it ever has.

Other than the riccia dying and the water turning cloudy one day it seems to work well.

If I notice anything else I'll add it to this post.

Allen
 

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I'm really shocked by this. I mean I know that glutaraldehyde is a strong disinfectant used in hospital etc. It's also toxic. I'm really shocked that it doesn't harm the aquatic life. It's probably about the doses. This really interests me. Thank you and I'll be waiting for your next posts.
 

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I was reading some companies MSDS sheet for it and it mentioned something like 'toxic to aquatic life in at .1 to 1.0mg/l for the most sensative species'. They never mentioned the species but a guess is that the cloudy water some get with high doses of excel is due to a die off of bacteria.

If I have done the math right (I probably have not;) ) then a 30 ml dose of 2% solution in 60 gallons is .26mg/l, pretty low on their "toxicity scale". That would lead me to belive that the most sensative organisms would be affected. Higher dosing woudl robably affect shrimp or snails, and lastly fish.

Using the same math, 5ml in 10 gallons is about .3mg/l. As I said though, I may not have converted to mg in a 2% solution correctly. I based my figuring on 100g/mol, or 10^5 mg/mol and assumed that one could figure a 2% mol solution in 1liter H2O. Please tell me if I am wrong.
 

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I remember reading some where about a guy that dose glutaraldehyde to a 100 gallon tank every day, just a few drops, I dont know the concentration but he said his tank was crystal clear and completly algae free, and he did this for sometime. Maybe BS. I think it was somewhere on this site
 

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Hoppy,

not sure if I follow how that relates, though it is amusing. If you are refering to using Excel as an "algae repellent or algaecide, that's not my intention. I really like excel but is very expensive in any quantity. If glutaraldehyde is an economical substitute, I'm all for it:)
 

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I thought about doing this last summer, but I decided against it thinking that they glutaraldehyde polymer would be much less pungent smelling than normal glutaraldehyde, usually aldehydes, amines, and sulfur containing chemicals stink. On a scale of 1-10 how bad is the smell? A pharmacist can order this for you, the product PDcare is available in the compounding catalogs.

The wooziness is probably a direct result of the irritant on the cells your nose. There is a review article that goes into the effects it can have on medical personell that use the stuff all the time, and have high exposure.
 

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Hoppy,

not sure if I follow how that relates, though it is amusing. If you are refering to using Excel as an "algae repellent or algaecide, that's not my intention. I really like excel but is very expensive in any quantity. If glutaraldehyde is an economical substitute, I'm all for it:)
I like Excel too, but when I hear of a tank that is always crystal clear without a bit of algae......well, it reminded me of George's testimonial to heating cables. Sorry, my laugh reflex gets out of synch sometimes.
 

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Nice work Allen! I look forward to hearing more and getting some of the gluteraldehyde once you reveal your source :D

I do have a question though, is the Gluteraldehyde a 2.8% solution or are have you mixed it to obtain a 2.8% solution?
 

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Discussion Starter · #14 ·
Hi Matt

I did a search for glutaraldehyde and found a number of places that sell it online.The solution i ordered is 2.5%.There are other concentrations out there.The higher level of glutaraldehyde the more expensive it is.I chose this one to experiment with because of the price and it is diluted enough that I could dose straight from the bottle.

This is only the first week of using it so I not sure if there will be any problems with long term expose for the fish or plants.
 

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The MSDS at Seachem clearly states that the major chemical in Flourish is glutaraldehyde. I doubt there will be long term effects with the use of only a 2.5% solution of glutaraldehyde

I think the increased concentration of glutaraldehyde is responsible for killing of 'fragile' algae when people dose 2x-5x the regular dose to get rid of algae.
 

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I was reading some companies MSDS sheet for it and it mentioned something like 'toxic to aquatic life in at .1 to 1.0mg/l for the most sensative species'. They never mentioned the species but a guess is that the cloudy water some get with high doses of excel is due to a die off of bacteria.

If I have done the math right (I probably have not;) ) then a 30 ml dose of 2% solution in 60 gallons is .26mg/l, pretty low on their "toxicity scale". That would lead me to belive that the most sensative organisms would be affected. Higher dosing woudl robably affect shrimp or snails, and lastly fish.

Using the same math, 5ml in 10 gallons is about .3mg/l. As I said though, I may not have converted to mg in a 2% solution correctly. I based my figuring on 100g/mol, or 10^5 mg/mol and assumed that one could figure a 2% mol solution in 1liter H2O. Please tell me if I am wrong.
Assuming the 2% is weight-by-volume: 2% w/v = 2 grams / 100 mL

30 mL in 60 gallons:
(2 grams / 100 mL) * 30 mL = 0.6 grams in 30 mL of the 2% solution.
If you add it to 60 gallons of water, 60 gallons * 3.78 L / gallon = 226.8 L
0.6 grams / 226.8 = 0.26 mg/L

5 mL in 10 gallons: (Still 0.26 mg/L since the solution volume and tank size are both 5 times smaller)
(2 grams / 100 mL) * 5 mL = 0.1 grams in 5 mL of the 2% solution.
Adding it to 10 gallons = 37.8 L
0.1 grams / 37.8 L = 0.26 mg/L
 

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I did a search for glutaraldehyde and found a number of places that sell it online.The solution i ordered is 2.5%.There are other concentrations out there.The higher level of glutaraldehyde the more expensive it is.I chose this one to experiment with because of the price and it is diluted enough that I could dose straight from the bottle.
Thanks for the info. If all goes well this should be another big money sver for the hobby.

This is only the first week of using it so I not sure if there will be any problems with long term expose for the fish or plants.
I don't think you are going to have any problems as long as you keep the dosing similar to Excel. Assuming Epicfish's calculations are correct I think it is funny that the Riccia in the 10g had issues while the riccia in the larger tank did not. Do you think this may be because the gluteraldehyde was diluted more in the large tank due to the tank's height? Did yo add the gluteraldehyde directly over the Riccia in the 10g?
 

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Assuming the 2% is weight-by-volume: 2% w/v = 2 grams / 100 mL

30 mL in 60 gallons:
(2 grams / 100 mL) * 30 mL = 0.6 grams in 30 mL of the 2% solution.
If you add it to 60 gallons of water, 60 gallons * 3.78 L / gallon = 226.8 L
0.6 grams / 226.8 = 0.26 mg/L

5 mL in 10 gallons: (Still 0.26 mg/L since the solution volume and tank size are both 5 times smaller)
(2 grams / 100 mL) * 5 mL = 0.1 grams in 5 mL of the 2% solution.
Adding it to 10 gallons = 37.8 L
0.1 grams / 37.8 L = 0.26 mg/L
Cool, I was right; though I see I took a more complicated path to get there. As for the calculations for 10 gallons, I was assuming 8.5 gallons since the standard 10 gallon tank is only about 8.5.

Allan, could you share where you ordered it from since obviously you had a safe and easy transaction?
 

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Urea instead of KNO3, KPO4, and KSO4 (if a K supplement is needed), and trace with Plantex CSM+B.

This should be interesting. =)
 

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Urea - Science Kit and Boreal Laboratories seems pretty cheap, compared to a place like this: Urea, FCC

Seems like these stores carry pure urea crystals as well as prilled urea (pellet form). I don't know how pure the prilled form is, so let's assume I get the crystal form of urea.

2.5% urea = 2.5 grams / 100 mL water
mL water required = 500 grams * (100 mL water / 2.5 grams) = 20,000 mL = 20 liters

From the cheaper site, for $15.50 plus shipping, you can get 20 liters of 2.5% urea!! Heck, if the prilled form was water-soluble and pure, it'd only be $8.70 plus shipping for 20 liters.

Urea crystals, if stored in a dry environment, aren't prone to decomposition, while urea solution is. So of course you shouldn't mix up all 20 liters, maybe a couple hundred mLs at a time.
 
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