What is wrong here? (nitrates)

[Reef_AK]

My nitrates have been on a steady rise the last couple of months, currently at 40ppm all other levels have been fine. Curious if there might be a problem with my filtration setup.
and I am not currently using RODI

On a 40gal w/two mj1200's, a remora hang on skimmer, and an eheim canister filter.

30lbs liverock, green bubble tip, leather coral, open brain, green stars, misc.mushrooms,
sun polyps, two percula clowns, bi-color blenny, royal gramma...

[davejnz]

Canister filter and not useing RO/Di water for top-off.Canister filters are good for one thing on a reef tank.That is to hold media(carbon,phos-ban,etc..)in them.If you have any type of bioballs,sponges,filter floss,ceramic beads,plastic strips or basically anything that will grow bacteria in the canister filter,then remove them.If you plan on useing your canister filter as a media filter,use small amounts of carbon(3tablespoons)and make sure to change weekly.If left in there too long,it will also provide a medium for bacteria to grow on and your canister filter will go "biological" on you.The reason external bio filters are not used in a reef tank is because they only grow the aerobic(oxygen)bacteria that are responsible for nitrification(converting ammo to nitrite then nitrate)Denitrification(the breaking down of nitrate)only occurs in the inner pore structures of LR and in the lower depths of your sand bed(this bacteria only lives in anearobic/no oxygen zones).Your LR and sand also provide nitrification,these 2 types of bacteria on the LR and sand need to be in balance with eachother.When you throw in an external "bio" filter,you disrupt that balance because they(bio filters)only filter the ammonia in water down to nitrate.The end result is a filter thats a nitrate factory.

[davejnz]

One more thing,you have no where near enough current in your tank.A 40 gal should have at least 5 water outputs.The total amount of current needed IMO for your tank needs to be around 1000gph.That is only a 25x turnover and would be the bare minimum i would use in a reef tank.

[Reef_AK]

If I take the Canister completely out of the picture, and add more current will that create any other problems? Thanks for your help.

[davejnz]

No,you shouldn't have any problems at all.The day before you remove the canister filter and for 2 days following,i wouldn't feed your tank much.You can remove the canister filter,although i would probably just remove all of the "bio" media in it and just use it as a carbon filter and another source for water current.I'd get the extra powerheads installed before removing the "bio" media as well.

[Reef_AK]

Thanks for your help, I'll give it a try.

[Fally]

Is lots of flow really that important? I have one power head in my 29 gallon. Seems to be quite a bit of flow... I am always afraid that I have too much flow when I see my polops or xena flailing around like a hurricane is going on in there.

[jerryc]

YES AND YES it will help keep bad outbreaks of datums down and will help
to suspend particles so that Thea will get to and be removed by your skimmer

But the amount has to do with the type of coral you keep hard to get
to much for SPS
Softies will get along with less. but still it will help with the above

[davejnz]

IMO,flow/current is the most important thing in a healthy reef tank.Lighting would be second.You can grow corals with 4-40w NO flourescents or with a $700 metal halide setup.Without proper current,you'll end up growing alot of algae as well.AS for your Xenia flailing around,I'd like you to look at this thread,there's a pic of Xenia growing in the wild with high flow SPS corals.The think about current is this.You want lots of current but at a low velocity.This can be achieved by different methods.You can use a 1"return from your sump instead of the typical 1/2" or 3/4".Direct your powerheads so that they hit the glass or LR so it disperses the flow.My 40breeder only has 1700gph which calculates to 42x turnover.I still have low current spots in the tank for my Frogspawn,Hammers,and Torch corals.

[Fally]

I think you forgot to link the thread, But I see what you are saying. That must be why some people use multiple outputs on their ruturn lines, to spread out the flow.

[Tanked]

Very well put davej.But u also have to remember that a filter system with good water movement does not mean that that there is good flow in the tank.Add a little flake food and really watch it and see were and how it moves .U need good flow in the tank other than a good filter system that moves a lot of water.

[davejnz]

Duh,here's the link i forgot to add.
http://captivereefing.com/viewtopic.php?t=2591&highlight=