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Discussion Starter · #1 ·
In my 10 gallon, about every 2 months I start to get green water. I think this is associated with oil accumulating on the top of the water, thus blocking off light. The hood on this tank doesn't allow for much evaporation so it keeps coming back.

Anyway, this is what my tank looked like 48 hours ago


I put in purigen and stayed at my girlfriends house. Came back, saw this:




I am VERY impressed. I thought it would slowly clear up, I didn't get to see but the time period was very short and the $12 was more than worth it interms of time.
 

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I suspect as much; GW tends to get worse during the day and better at night. The fact that the tank appears better at night is probably not due to the Purigen.
In my experience green water does not come and go day from night.
 

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I use Purigen in all my tanks. My water seems clearer. I have never had green water in any of the tanks so I cannot say if it works on that. However,. there has been some discussion on aquaticplantcentral dot com in the past of the possibility that Purigen could clear green water as it filters at a molecular level. Cause and effect is difficult to prove, but I have often wondered why I have never had green water even in a soil based tank that I set up. I also used Purigen in that tank.
 

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Cause and effect is difficult to prove...
Well said. Correlation does not imply causation (i.e. If there is a fire, the bigger the fire, the more fire trucks there are. Therefore, fire trucks cause fires....see the faulty logic?).

I guess Purigen might be worth a try if it really does prove to be effective at preventing/removing green water.
 

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Discussion Starter · #8 ·
First, the blinds on the window are always closed during the day. It has been very hot so they were just open to open the window.

I have seen no change from green water to clear from night to day. The GW has been a problem for almost 3 weeks. It has also happened 3 times now. I get "oil slicks" which I think is due to the hood. When they happen, my tank begins to turn green. I would guess the fact it is pretty low light combined with fact the oil blocks light is the issue.

Usually my GW would slowly go away when I finally got rid of the oil slick. This happened much quicker. Maybe it did a better job of getting rid of the oil slick than my way, maybe it just filtered it. Either way, if I did not put purgien in, it would not have cleared up, I am atleast convinced of that.

I did not expect such dramatic results, I wanted to run it for other reasons and hoped it would help. I figured it would just slowly clear up. So even if the Purgien didn't do as much as I thought, I am convinced it solved the problem.
 

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Purigen removes impurities from the water. It removes nitrogenous compounds that later release nitrates, nitrites, and ammonia. It's great, yes, but does it really cure that kind of GW?

When you put the Purigen in and left for your girlfriend's place, were the lights on a timer? Or were they off the whole time?
 

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Discussion Starter · #10 ·
Lights were on a timer.

It may have just got the oil slick off the top of the tank (which has never totally gone away before I used this). My bag is very green in color as well.

So yeah, there really isn't any other variable here, I am convinced myself. Someone else should give this a try for sure and see if they get the same results. I understand my experience isn't conclusive but I don't get how else it would have happened.
 

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1. The purigen filtered out the green water. It is fine enough and "sticky" enough to do that. It did not cure the cause of the green water. If you remove the purigen it will come back or the purigen may reach a saturation and the GW will come back then.

2. I don't think the film on top is the problem but a platy, mollie, guppy or any other livebearer will consume said film happily. Buy one or two. They're worth the buck or so for that.
 

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Discussion Starter · #12 ·
1. The purigen filtered out the green water. It is fine enough and "sticky" enough to do that. It did not cure the cause of the green water. If you remove the purigen it will come back or the purigen may reach a saturation and the GW will come back then.

2. I don't think the film on top is the problem but a platy, mollie, guppy or any other livebearer will consume said film happily. Buy one or two. They're worth the buck or so for that.
I think my statements came off a bit too strong. I don't think that Purigen was the end all thing here, I was just very suprised how much it can do so quickly. I have been running it in my 29 gallon for longer with great results as well, my 29 just doesn't have issues like my 10 had. My hope is that it just doesnt' come back, we will see.

I really don't know what the cause of the GW is. I know it's next to a window but that doesn't seem to matter much as most of the time the tank is clear. I bring up the oil slick (which is now gone) because that is the first thing that happens before I start getting GW.

Anyway, I guess I just wanted to show a visual of it and make it clear that this didn't go away on it's own. Will it come back, who knows? It did save me a bunch of water changes, though my plants did suffer more than I wished.
 

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Thought i would update this old thread.

I had GW for about 2 weeks, and put in a bag of Purigen. Water was crystal clear about 3 hrs later.

Fast forward 2 weeks, GW is back again. So Purigen will help, but it definitely will not work for the long run. Still looking for a cause to my GW.

Tank specs:
2.5Gal
27w Hampton Bay CFL
Eheim 2211 *new*

Ferts: using Pfertz NPK & M, 1 pump each after WC, 1x week

Fauna: none
Flora: HC, Blyxa japonica, dwarf chain sword

Here is a before and after pic of the effects of Purigen (brought to you by my phone camera):

Before Purigen:


After Purigen(same day):


2 weeks later:
 

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I've had similarly impressive results.

However, I feel it's only really useful in the first six months of a tank's life - for dealing with bacterial blooms and green water mainly. After that it might not be worth the hassle of regularly recharging etc.

And of course it doesn't cure the cause of the green water, which will return literally overnight if conditions are right (as you saw for yourself)
 
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