[urbnbtta]

hello, i might have just pulled a doozy. i'm not very good at pre-planning and asking questions BEFORE i set out.

i'm setting up a new natural tank, and am using:

regular gravel and used brita filter innards, topped with fluval stratum.

brita filter innards are listed as coconut shell activated carbon and ion-exchange resin.

did i make a huge mistake? does anyone have a strong grasp of what the ion-exchange resin will do in my tank? my idea was that maybe plants could make use of minerals. should have asked first.

also, for hardscape i picked some pumice i snagged from anguilla. it was rinsed, boiled, and submerged in cold water. is this going to leach salt/adversely affect my water over time?

from the brita faq:
What ingredients are found in a Brita® Pitcher Filter?
The Brita® Pitcher Filter contains activated carbon and an ion-exchange resin. All of the ingredients in the filter have been approved by the Water Quality Association. As you may know, activated carbon is widely used in the food and medical industry. Its function in Brita® Filters is to reduce the chlorine (taste and odor)1. The activated carbon utilized is made from coconut shells that have been subjected to a special heating process that produces a large surface area capable of maximum absorption. The ion-exchange resin acts like a magnet and reduces mercury, copper, cadmium and zinc1.
1Substances reduced may not be in all users’ water.

 

[Franco]

the only problem i can foresee with the brita inards is that you don't really want to put concentrated heavy metals in your substrate

 

[Diana K]

Ion exchange works like this:
A material has an affinity for many minerals. It wants to hold onto some stronger than others. When something comes along that it likes a lot some other mineral will get kicked off the resin to make room for the new one.

In soils this is called Cationic Exchange Capacity, and it is good. Soils with high CEC will hold certain minerals in a way that plants can remove them, and the plants use these minerals to grow.
Whether the Brita resin will do this for you under the substrate is a good question.

Whether the used Brita media will introduce toxic metals to the tank is another good question.

If you are on a municipal water system get one of the annual reports and see what it says about the heavy metals. If there is none or almost none, then I think the risk from the Brita filter media is low.

Coconut fiber Carbon has been shown to be of limited use in removing the toxins that might be found in an aquarium, and once it is buried in the substrate you cannot remove it. It is stuck there. Most carbon does not release whatever it has collected, though, so this becomes a possible lodging site for microorganisms. If it is in contact with good water movement (not under the substrate) then nitrifying bacteria will grow on it. Under the substrate there is not enough oxygen for these organisms, though.

Pumice is OK in an aquarium, usually does not release toxic metals. If it was in the ocean there will be surface salt and minerals, but these are easily rinsed off with some thorough rinse-and-water changes. If it is sharp pumice this can cut the fish and plants. Do not use it if it is sharp. I use a small lava as a plant medium in a planted sump, and in all the rinsing I did I did not find any sharp pieces.

Regular gravel, from non-limestone parent material is neutral in an aquarium. Decent cover to hold the plant substrate in place, but not so great as a planting media in itself.

 

[urbnbtta]

thank you guys, this was hugely helpful! thank you diana, for taking time with such a thoughtful and insightful reply. 700 gallons! wow. definitely bigger than my apartment.

ok, so my nyc report for 2009 is as follows. i don't know what it all means, can anyone teach me what to look for and what this report means for my few gallons of flora and fauna?

pgs 10-11, i think are the relevant tables.
http://www.nyc.gov/html/dep/pdf/wsstate09.pdf

thank you!

 

[Franco]

I use Caribsea ActiveFlora Midnight black and it is just crushed up pumice/lava rock. It doesn't have any sharp edges and I was able to get it for a couple bucks a bag on clearance at Petco. It looks really good and hides substrate debri like you wouldn't believe. It looks totally clean but if I hit it with a gravel vac, boom! crap central. Having the substrate always look dirty is usually one of the drawbacks of black substrate. It also doesn't compact but seems to lock together slighlty making it really easy to plant with. Runners, new leaves, and Malaysian trumpet snails move through it like its no big deal.

Your NY water quality testing is really extensive. Nothing was jumping out at me except that I am surprised by the pH swing. Ours always tests within +/- .25 of the average and offgasses to 7.6. Although we don't have acid rain at all so that could be a cause for fluctuations.