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RafflesGold Forums > Discussion Area > Green Water, Filtration and Tank Setup
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While doing water change....and back flushing it, my canister is usually is not turned on till about max 20-30mins....

So does too effect bb? and what about the air pocket created after backflush...does this help while i wait to dechlor my tank water then start the canister up again?

i never took this into account....that it would effect bb!
QUOTE(Kinder @ Sat, 15 Dec 2007 2:05 pm) *

Seachem Prime...says it detoxifies nitrite and nitrate,
do anyone know to what nitrate&nitrite changed to...?

The trouble with Seachem Prime is that they won't tell you what's in it and you can only infer the ingredients based on what they claim about its effects. It probably contains sodium thiosulfate to neutralize chlorine. It probably contains sodium hydroxymethane sulfonate (aka ChloroAm X or Amquel) to bind the ammonia that is released when chloroamines are disassociated. It probably contains EDTA (ethylene diamine tetra acetic acid) which is a chelating agent that will bind up heavy metals so they are not biologically active. All of these also act as salts which compete with the nitrite for space to cross the gill membrane, thus making the nitrite less toxic. Nitrate is a larger molecule and inherently less toxic, but all these chemicals also make it less likely to cross the gill membrane.

Any time you turn off the flow to a biological filter (e.g. in cleaning or during a power outage) the primary concern is oxygen depletion. It has a high oxygen demand and the nitrifying bacteria will be killed off by oxygen depletion. Best to do some spot checks to make sure your normal routine is not harming the bacteria.

QUOTE(bekko @ Sun, 16 Dec 2007 6:56 am) *

Best to do some spot checks to make sure your normal routine is not harming the bacteria.

What d you mean by this?

And the only ingredient stated on the bottle is complexed hydrosulfite salts


If you are shutting your filter off for some length of time, you should check the dissolved oxygen of the water coming out of it when it is first turned back on. That will give you some idea of whether it is getting low enough to harm the nitrifying bacteria. As long as you have several parts per million of oxygen left when the circulation is restored, the filter should be OK. If you leave the filter off for about the same length of time every time you do the exchange routine then you would only have to check it once or twice.

Alternatively, you can just drain the filter when it is shut off. The media will not have time to dry out and this will prevent oxygen depletion.

The rate of oxygen depletion will be different for every type of filter and the load on the filter so there really isn't any rule of thumb to go by. Actually, everyone should have some sense of how long their filter can go without flow and/or aeration in case there is a power outage. The first thing that dies in a power outage is not the fish, but the filter. Then, days later, the ammonia spikes from the filter disruption and the fish get sick from the stress. In a prolonged power outage, the best thing to do is drain your filter and spray it with some water every hour or so to keep the media damp.

ST and ampule are complexed hydro sulfite salts. EDITA is not, but it is by far the least expensive chemical for chelating heavy metals and I cannot imagine they would be using anything else.

Hi steve

Thanks for the reply, i really didn't have any idea about the possible oxygen depletion during WC and its adverse effect on BB.

Anyhow i plan to measure my dissolved oxygen level pre/post WC. And in the mean time will try to keep my canister media basket in the bucket with an airstone. Coz i usually save some water from the tank for my plants....recycling!
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