Canister Filter To Remove Or Not

[dobz55]

Hi all, I have a 50 gall set up,
27kg live rock
Deep marble chip bed
Red sea prizm skimmer (useless)
1 x Canister filter output 1000 lph
2 x internal filters combined capacity 2000 lph
T-5 lights 4 x H/O
2 x T-8 Acitic Blue lights,

1 x Foxface
1 x 6 bar Angel
2 x Tomatoe Clowns
2 x Yellow tail blue Damsils
1 x Domino Damsil
1 x BTA
1 x Carpet Anemone
1 x Coral shrimp
about 12 crabs
Couple Bristle worms,
some other worms look like common garden type
At least 1 and possably several pistol shrimp
10 or so assorted snails
several bristle star fish ???

any way Tank has been set up since early October 06 and I have never ever been able to achieve zero Nitrates, I do 1/4 water changes ever week, I add 7 ml stress coat, and 7 ml calcium +3 at each water change, my todays test results are

Nitrate 20ppm
Nitrite 0.2 ppm
Ph 8.1
Alk my test kit reads normal low high, it shows normwl
Ammonia just get a reading (test just starts to change to the first colour but doesn,t reach it.
Phosphate 0.1 ppm

my question is does any one think that I can remove the canister filter and not cause any harm as I feel it may be contributing to my current Nitrate readings, I cannot replace the canister filter with a sump as I don,t have one , I can if needed put in another power head or 2 , if I remove my canister filter will my water conditions deteriorate , as I will have no way of then removing minute :eek3articles from the water as I only have porcelain?? in my internals and I also use Pocerlane/glass in my canister along with Phosphate and Ammonia pads

[leebca]

Just some observations:

The live rock quantity is short in order to effectively handle denitrification. The target should be more like 1kg per gallon of display tank water volume.

The marble chip sand bed may not be performing its full potential of denitrification either. I would need to know the particle (chip) size range, actual depth of the bed, and when the tank cycled to determine its functionality.

The aquarium system you have can handle about 12 bio-load units. You currently have in the system about 19+ bio load units. The system is overstocked.

Between overstocking and potentially sub-effective denitrification, the cumulative effect is that there is too much nitrogen waste in the system which your biological filter can't handle. The only solution is to either reduce the bio-load (remove marine life) or utilize effective (expensive) chemical filtration. Thus I would advise don't remove the canister filter. It is probably the only reason why the system is doing as well as it is. And since it really isn't doing that well (poisons are detectable) you might consider adding another canister filter.

[dobz55]

Thanks Lee, marble chip size is sand grain size particules, very fine, depth is between 4 and 5 inches,the Tank was set up early October and cycled for 5 weeks before any thing was added,in regards to adding another filter would you suggest another canister or would another internal power head do the same job, it is strange though in regards to my system all of the inhabitants appear to be happy and well my only losses have been 1 x coral beauty in november 2 days after it was added, 1 x domino early December 1 day after it was added and 1 x peppermint shrimp 10 minutes after it was added I believe my LFS may have damaged him during capture, when added to the Tank he landed smack bang in the middle of the carpet Anemone and that was it.

[leebca]

If the Foxface is getting proper nutrition (and a lot of greens) then it is producing a large amount of waste. It will also grow pretty quickly, like most Rabbitfishes do. These kinds of fish are big polluters. ;)

The poisons in the aquarium creates stress on the fishes. Have you considered the possibility that the fish deaths were the result of those poisons? The fish already there are getting used to it and spending a lot of internal energy to compensate for the current conditions. You don't see these stresses in the fish except by evidence -- the fish gets sick (not a healthy life) or they soon die (a shortened life). What is seen is the water quality which has tested as not being in good shape. There should not be any evidence of ammonia or nitrites.

Repeat these tests with a reliable and sensitive test kit, 1-2 hours after a feeding and see what they are. The system water should show "0" or "None Detectable" by a sensitive test kit.

I would prefer to see a reduction in bio-load so that after a feeding there is no detectable ammonia or nitrites, several days in a row. However to compensate for this scenario, a canister filter with ammonia and nitrite absorbents is needed. You may also need a phosphate reactor or absorbents, if nuisance algae get out of control.

I would go with the second canister of 90+ gallons/hour rating, then add more internal circulation later on, if your aquarium shows continual 'brown algae' growth.

[dobz55]

Thank you Lee, I very much appreciate your input, I agree I do believe my test kits are not overly accurate, just llast week I re aquascaped my tank and repositioned 2 of my power heads, I don,t know if this did it or not or whether my tank is finally settling down,but unbelievably the algae growth has almost stopped the DSB has cleared and there is no brown at all there is a little green algea and that is all.my glass is remaining relitivly free of growth (apart from the back where I don,t clean leave it as a food source)I have increased my surface movement 10 fold be positioning my power head outputs close to the surface and attaching a plastic tube to the canister filter so as that it is flowing across the top of the water I have one power head blowing directly over my rocks and my BTA has moved out and into the stream, I shall get another canister onto the tank as well this weekend

[dobz55]

ps I have added phosphate pads and nitrate pads to the canister filter