Carbon

[Fay]

Have you tested the carbon you use; could be adding Phosphates to your tank.

[reef]

Normally only cheap carbon will add phosphates,

Even some of the more exxpensive ones add a small amount.

[Fay]

I don't know about cheap I asked for the best carbon at Hollywoods

[Fay]

I've been advised to use the carbon Jansens package, Brendan said it has never tested possitive.

[cracker]

The Jansens bags are all good.

And cheap, It is used for hospital applications as in dialysis machines apparently.

[lduncan]

I use purigen from Seachem instead of carbon. It's great stuff, (at a heafty price though, luckily I didn't have to pay for it. Got it courtesy of the insurance co after the fire)

Last for ages, had mine 6 months, with plenty of life left in it. It's a synthetic polymer which you can recharge using bleach. Water looks crystal clear when it's running. Apparently it can directly absorb nitrate. It doesn't leach once saturated either.

Layton

[reef]

Layton, does the purigen look like zeolite

[reef]

..

[lduncan]

no, it's tiny beige balls less than 2mm in diameter. Turns dark brown when exhasted and ready for recharging.

It is a specially created polymer made to mimic the properties of zeolite, but with saltwater in mind (no need to worry about calcium interfering in ion exchange), with the huge advantage of being able to be recharged. It does loose effectiveness after each recharge though, so it won't last forever.

If anyones interested I could get a 20Litre drum of the stuff imported for only $600.... US of course. :lol:

Layton

[reef]

what you think of this layton

http://www.wetwebmedia.com/ca/cav1i3/zeovit/Zeolite_Filters/Zeolite_Filters.htm

[lduncan]

Well, i think it is written by someone who has a very basic understanding of zeolites. While I don't know much about zeolites at all, I know enough to know that the article is pretty lean on even a moderate understanding of them.

There are industrial chemists which spend there lives studying categorising, and even creating zeolites, it is a simple name for a very broad group of minerals, all with very different properties.

The way he explains it, there is no need for the zeolite at all. All it is doing is acting as a surface for bacteria to grow, providing regions for an oxygen gradient where different bacteria can do their thing in reducing nitrate to nitrogen gas. The surface area available on most activated carbons it much greater than a similar volume of zeolite, and would make a much better media if this were the case.

His explanation really discounts the ion exchange process, and says that it effectively acts as a DSB.

I don't think this is necesarily the case. I don't know enough about zeolite, either natural, or synthetic to say for sure, but I think ion exchange is more important than the bacterial processes, for the simple reason that the pore size in most zeolites is far too small for bacteria (by a factor of 10) and the surface are colonisable by the bacteria is too low.

So I think when the right zeolites are used in marine tanks, their effect is more from the ion exchange rather than the bacterial action.

Layton

[reef]

Well, it does say that it removes ammonia, which means low nitrates.

[lduncan]

But it also says that bacteria blocks the surface. This would slow the ion exchange process to nothing pretty quickly.

I still think there are more effective methods than zeolites, to reduce nitrate.

Layton

[cracker]

I am running poly filter from the States. A polymer impregnated filter wool that removes phosphates, ammonia, plus a heap of medications and other materials also.

Higly recommended by Fenner, so I got some.

Bloody expensive, but seems to do the job, but probably would be better if I put a decent amount in!

I'm a bit tight to stick too much in as the price is phenomenal!

Type in "poly bio marine" in google and look for POLY FILTER

[cracker]

10 micron material available in Auckland will stop blocking bacterial colonising materials. It also pulls heaps of DOCS from the water column prior to the skimmer.