Today I'm going to talk about Purigen, a synthetic filter medium made by Seachem. I bought mine on Amazon. The 100ml size comes in a sealed filter bag and treats 100 gallons. I have Amazon Prime so it was $8.15 with free shipping.
I started using Purigen 4/11/14 after my bout with ich. After treating for ich I ran a carbon filter for a few weeks. Then replaced it with Purigen. If you have a HOB filter you put the Purigen in the same area you would put carbon or charcoal. You can also use it in canister filters. I have a HOB that holds a foam block, a carbon bag and a bag of ceramic cylinders. You simply rinse the bag and put it in your filter. You should not use it with slime coat additives because they will damage it. Prime is ok to use.
The instructions say Purigen can last up to six months. It starts as tiny white spheres and progressively darkens to a brown/orange color. Mine was very dark within 6 weeks. I'm not sure if this will be typical or if it is due to leftover ich medication?
When the Purigen changes to orange/brown you can recharge it. It is a bit of a process and not really as simple as they make it out to be. You remove the packet and soak it in a 1:1 solution of bleach and water for 24 hours. It will turn back to white. Then you rinse it and soak it in a concentrated solution of Prime and water (2 tablespoons Prime per cup of water) for 8 hours. Then you have to buffer it with Discus Buffer or Neutral Regulator for 4 hours. Then you should check for any residual chlorine before adding it to your filter.
So, to recharge you need: Prime, Neutral Regulator (took me 2 pet stores to find and cost $12) and chlorine test strips.
When I completed the process I noticed that that Purigen smelled terrible. It reeked like dead fish! I googled this and learned that the smell is common. It is even discussed by Seachem in their forum. They said the level of stench varies from recharge to recharge. They said that it is caused by the production of amines and is normal. Just so there is no chlorine, not to worry.
I was worried. I soaked it in Prime again and the smell was a little better. I tested for chlorine and it was 0.
I replaced the newly recharged Purigen in my filter and stressed for 3 days, worrying that the tank would crash.
Everything has been fine. The fish, frogs and plants are all behaving normally, and the Ammonia alert is not showing any ammonia.
I love how clean and clear the water is with Purigen. It really is amazingly, crystal clear. I feel like it is very healthy for the tank.
The recharging process is a hassle and worrying about chlorine left from the bleach stresses me out. Plus, the smell was just awful. I'm not sure I will do it again. I'm inclined to just buy a new bag when since it is less than $10.
I also have a bag in my terrarium filter.
Overall, I think it's a great product and have been really happy with how clear the water is. I will keep updating on this journal, when I have to recharge it again and whether I decide to do that or just pitch it.
Here is a picture of our cockatiel on a Lego car, for some comic relief after all the filter talk!