Since you don't know what the toxins were ... I would be worried it might be adhering to the silicone. So, I'd wash it out completely a few times, and then recycle the tank, and see if some pond snails proliferate in it.

black rubber seal, the sort you get on car windows and the like.

That could be any of the synthitic rubbers or PVC, we made compounds that were used as door/water seals

The most common plasticizers were DIDP, DOP (DEHP) and DINP that I used.

Most PVCs contain heat stabilizers, often lead or other heavy metals

should I do carbon in the filter first to be safe?

I would add carbon

Sophia, if you want to test the tank to see if its safe I have some surplus fish here that you could use.

Sophia, an article of warning about your problem for the AW would be wonderful. Then all may learn from your mistake

The problem with carbon is that it can extract a lot of toxins from the water but can just as readily dump the whole lot back in. Water changes remove the toxins--full stop.

The problem with carbon is that it can extract a lot of toxins from the water but can just as readily dump the whole lot back in.

I have seen that written often but have never seen a source for this, is it really true that once all the pores are full it will dump the bound toxins/organics back out?

:facepalm: complications :digH:

Activated carbon removes organic compounds from aquaria by adsorption and absorption principles. Both processes involve the transfer of the adsorbate (pollutant) from the liquid phase (water) to the solid phase (carbon). Adsorption is the primary sorption mode relying on electrostatic Van der Walls forces. This attractive “force” forms relatively weak bonds between the carbon and adsorbate. In theory activated carbon could release or desorb what it removed at some point. But practical experience with aquarium filtration and laboratory experiments show desorption rarely occurs or causes any type of “toxic release”. Bacteria readily colonize the outer surface of the activated carbon and consume some of the sorbed organics. The bacterial action reactivates a small portion of the carbon and perhaps prevents desorption.

http://www.hallman.org/filter/gac.html

So, in practice and experimentally, no, it won't release toxins back into the water.

how about I put it in and leave it for a couple of days to suck it up and then take it out again.

Does anyone have an opinion on that idea?

I will say that I have no experience using the stuff ...

Sure .... take it out after 6 weeks and replace if you want. Like any material the carbon will become a bacterial filter as it loses its absorption abilities.

Here's something interesting I just learnt: The rubber I used was most likely EPDM and reading through this link it says it's often used as a pond liner.

http://en.wikipedia.org/wiki/EPDM_rubber

why did it kill my fish then - is that it's ok in greater amounts of water? :-?

Perhaps it is slightly different stuff. You didn't use a silicone or something that had mould inhibitors in it did you?

Perhaps it is slightly different stuff. You didn't use a silicone or something that had mould inhibitors in it did you?

Working at a building supplies company, I have been told there is only ONE product that does not have the mould inhibitor in it, (So I steered away from building my own tank). Check the sealant, they normally brag about how great they are at reducing mould build up, and not so much about how many other things it will kill in the process.

http://www.hallman.org/filter/gac.html

So, in practice and experimentally, no, it won't release toxins back into the water.

1 non-peer-reviewed on-line paper, with 1 reference (to another on-line report), written by a obscure and unknown writer of questionable background and experience, means precisely nothing.

You seem to like finding articles for anything and everything. This in itself, is not a bad thing, but maybe you should choose more wisely next time who you reference as evidence.

The catch 22 is that you are coming across a smart-alec, and I feel that, whilst your intentions may be good, You're beginning to irk a few with constant over-examination and over-doing it. any monkey can use Google scholar to find papers to prove or disprove just about anything.

Quality articles rather then Quantity would be a good move for you, I think.

:smot: :slfg:

I have been advised by another person who I trust that carbon doesn't dump the toxins back in, it just stops adsorbing, so the point being made is not necessarily wrong even if you don't agreed with the approach of the poster.

To answer Caryl:

I didn't add any silicone, it was just rubber with a slit cut in it, squashed around the divider and jammed in the tank.

:smot: :slfg:

I have been advised by another person who I trust that carbon doesn't dump the toxins back in, it just stops adsorbing, so the point being made is not necessarily wrong even if you don't agreed with the approach of the poster.

[/

Personal opinion is nothing unless you can back it up. My interest in this was because I was looking at the possibility of regenerating activated charcoal and basically you can't do it unless you have access to 900 deg C chambers, or another substance that binds more strongly than activated charcoal. For people to say that it releases the toxins back into your system goes against the evidence, and is needlessly scaring people and wasting their money. Now I could say that it doesn't release toxins back, and not provide a link but an explanation of the reasons why is quite useful to understand how this all works. This science is so old I doubt that there are any peer reviewed papers available online.

edit: screw-it....

I don't have time for this. Enjoy wasting your, and everyone else's time with inane articles that mean absolutely 0.

The "inane" article you refer to was authored by James R. Layton, a chemist working for Aquarium Pharmaceuticals.

And we were meant to guess at his credentials??

Sorry for asking the question in the first place :facepalm:

Lets try not to get personal here.

There are some facts with this case which I was trying to relay.

1 The fish died and were poisoned.

2 Carbon would probably remove the poisons and may or may not dump them back again.

3 Water changes will remove the poisons.

what I want to know is why EPDM is used for pond liners but killed my fish ...

If it was made for a use where it did not need to be food safe or by inference fish safe it may have had chemicals added for all sorts of reasons that have leached out. All of these compounds are like rubber which is a bit like DNA and is a helix that is then (in the case of natural rubber) cross linked with sulphur that then increases the modulus. This means that if you stretch it out it will better return to its original shape. I think this occurs with diene being cross linked with peroxide.

In a previous life my kids had those magic bouncy balls a couple of years before they came on the market. Polybutadiene is the synthetic rubber used in making them and was also used in the tyres used to stop aquaplaning. I was playing around trying to develop a cheap golf ball. It didn't work as a golf ball but made really good magic balls.

true, the stuff I bought was like this stuff so I guess they wouldn't necessarily make it fish safe because it's not a fishy product