# Purigen on HOB question



## pretty-nifty (Nov 4, 2009)

Has anyone used Purigen on their HOB filter? If so how have you done it?

Have you taken the cartridge out completely and put the bag in the tray?

I have two Penguin 150s on my 29G. Can I put just purigen on one of them and the Marine land cartridge on the other?


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## larry.beck (Jul 31, 2009)

With Purigen you really need to use one of their little bags. I have a bag in one of my HOB and it really polishes the water nicely.


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## pretty-nifty (Nov 4, 2009)

Yeah, do you use it exclusively and have taken out the cartridge or do you have both the cartridge and the bag of purigen in there?


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## borohands8593 (Apr 15, 2009)

Well its not an exact science but I have an overcrowded 29G and am not a fan of doing water changes weekly because of my crazy work schedule. I used purigen as soon as the cycle was almost complete to help with the nitrates since I am attempting to breed a few Tangs and nitrates would not be acceptable! My ammonia and nitrites have been 0 and my nitrates even after weeks without a waterchange and heavy feeding never climb above 10ppm.

I have a Penguin 350 biowheel filter so I basically have the same two baskets you have just in one filter instead of two. I bought 250ml of Purigen and divided it into two bags. In the front slot I left the marineland catridge which I never change out only clean in dirty tankwater once in awhile (to prevent killing any bacteria). Behind them I have a Large whisper cartridge which I have the Purigen bags laid in the bottom and extra cotton media in the top. I dont touch these but once every few months.

My belief is that Purigen could possibly starve out the bacteria on the biowheels making the main attraction to this filter ineffective. Needless to say in a well established tank there are a ton of bacteria on the sand, living in the million crevices of texas holeyrock, and on the tank itself. Also the airstone is an awesome bacteria grower! Whether or not there are enough bacteria in a tank to keep it cycles is another debate for another topic, but I am in the belief that there is not in an overstocked tank.

That is why I keep the original marineland filter in front, to hopefully have a healthy bacteria colony to constantly supply the biowheels. The purigen in the bottem of the basket allows enough water to pass over it untouched with the bio-load from the tank to keep the bacteria on the marineland filter and biowheels healthy and fed. Any extra will be consumed by the Purigen which will also help polish the water.

I have had this setup now for about 3-4months and my water has been crystal clear since week one and as previously mentioned, nitrates never climb above 10ppm. The fish are all very healthy and happy and I hardly do water changes but once a month. ALthough this isnt exact science, as I can not count the number of bacteria on surfaces or biowheels, I believe as the Purigen fades I should have enough bacteria in the tank to consume any slowly rises bioloads.


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## larry.beck (Jul 31, 2009)

pretty-nifty said:


> Yeah, do you use it exclusively and have taken out the cartridge or do you have both the cartridge and the bag of purigen in there?


I have quilt batting over the cartridge frames but nothing inside them, providing purely mechanical filtration and space for some biological buildup. Just that and the bag of purigen.


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