too much filtration?

[jona74]

I have a 46g bowfront with about 38# of live rock, a PennPlax canister filter designed for a 100 gallon tank (w/ ceramic and carbon media), aqua c remora skimmer w/MJ_1200 pump, and about 40# live sand. I am getting ammonia and nitrate levels of 0 since I established the tank. my nitrates continue to climb despite weekly 10g water changes
live stock includes:
2x Oc. clowns
3x bluegreen chromas
1 bangaii cardinal
1 blue tang
1 royal gramma
emerald crab, cleaner shrimp, and 3-4 various snails, etc.

I read somewhere that having live rock coupled with another source of bio-filtration can cause issues with high nitrates (something about competition between the different filter's bacteria?). is this true? should I remove the ceramic and/or carbon from the canister? is the LR and sand sufficient enough in their bio filtration?
Thanks in advance

 

[Mebbid]

A tank's bio load can only accommodate a certain amount of bacteria due to available food. It will end up distributing itself among the available spaces according to water flow. The denitrifying bacteria should all be located on the live rock so the available filtration shouldn't be an issue. I would look more at how much you are feeding the fish as the cause of nitrates rather than the filtration.

How much and how often are you feeding your fish?

 

[TheTodd]

And how frequently are you cleaning the canister filter? Stuff builds up in there fast, so most filters require weekly cleaning. If that is not happening, there's the source of your nitrates. You would probably do just as well without it.

 

[mr_X]

How big is the tang? How often and how much are you feeding?

 

[jona74]

I have researched feeding quite a bit, and have read varying suggestions from as much as 3x's a day to as little as every other day! (All suggesting to only provide enough food for 2 to 3 mins) I have been doing twice daily using a cooking flavor injector filled with marine cuisine to better the regulate the amount of food I administer. I am also using omega one algae sheets for my tang to graze on for about 4 to 6 hrs daily. (She is only about 1.5 inches). I do realize she will outgrow my tank, but the guy at the LFS said she be fine until she gets bigger.

As far as the canister, I have been cleaning it every other week, and just changed the filter floss this past weekend.

 

[TheTodd]

IMO, the filter needs to be cleaned more frequently and the fish need to be fed less frequently. I typically feed every other day and have never had issues with nitrates or fish starving. I would consider losing the canister, or maybe just running it from time to time for purely mechanical filtration. The live rock, live sand and skimmer should be all you really need.

 

[mr_X]

Twice a day is way too much. This is where your nitrates are coming from. I have fed a 150 gallon tank I maintained twice a week for over 2 years and nothing starved. As a matter of fact, the fish were quite fat. Also, when I fed them it didn't take them 2 or 3 minutes either. It was more like 30 seconds.
Enough food for 2 or 3 minutes is a lot of food.
I would cut back on feeding to at least every other day and increase water changes.

Just take all the food you feed the tank in a week and put it in your hand. Are you removing this much waste?

 

[jona74]

Thanks for the input! Greatly appeciated. I will definately reduce the amount I am feeding.
After a few more water changes and a good cleaning of the canister, should I expect to see a drop in 'trates? what is a good indicator or "method" i can use to determine if the dentrifying bacteria in my live rock is doing an adequate job with nitrates?
I know the goal is ZERO, but is there an acceptable range in which I can be sure that drastic measures will not have to be taken to lower the nitrates? (kind of an absolute maximum?)

 

[mr_X]

The amount of time until you see the nitrates lower will depend on how much nutrients must be removed. The method would be just what you are doing- testing the water.
You are going to hear various answers about the nitrates, but I would say at 20 it's time to address it.

 

[jona74]

ok, so i am performing a 30% water change and noticed that while using a turkey baster, There is a ton of white flakes coming of some of my live rock. What does this mean? is is a bad thing?