Stocking Questions and High Nitrate Concerns

[Machina]

About three months ago i decided to turn an old 7 gallon minibow into fish/invertibrate marine tank (no corals)...this marked my entry into the marine hobby. I've done plenty of reading and noted heavy words of caution in setting up such a small a marine tank; however I chose to go ahead with it anyhow, fully aware of the risks. At this point I've had limited success, and have seen it all...bubble algea, decreasing pH, ich, loss of fish, and now a staggaring high nitrate level. Resultantly, I am open to any suggestions, specifically in terms of filter media, tank maintanance, and stocking.

 

Currently I have several hermits, a couple turbo snails, an emerald crab, a pink tip anemone, and about six pounds of live rock. Up until a week ago I also had two small percula clowns, but it would seem that my inexperience has sadly led to their demise.

A more detailed inventory of my tank can be found here: http://www.aquaserve.com/WetNet/Misc/ShowS...nk.asp?ID=15329

A picture of my tank can be found here: http://andrew.mattmcleod.net/blog/images/microtank.jpg

I am very rigorous with my water changes and testing, but obviously there's a puzzle piece I'm missing.

 

Recent Cronology:

1) Noticed sliding pH levels (from 8.1 - 7.8). Began adding Kent pH buffer, it's now back up to around 8.2.

2) Went out of town for a couple days, came back and there was evidence of ich on one of my clowns. Taking the advice of a fish store, started treating with Kick-ich and soaking food in Garlic Guard. It wasn't too long before both clowns perished though.

3) Hindsight has shown me that one of my clowns was stressed. I figure this was due to his recently cramped quarters resulting from the addition of more rock.

4) I now realize that my nitrate is way too high, sitting somewhere around 30-40ppm (hard to distinguish the upper scale on my Seachem test kit).

 

Water Chemistry:

Things that are standing out are my high nitrate, and my alkalinity (has been sitting high ever since I started with the pH buffer - 4 meq/l). I was originally doing 10% water changes per week, but have now upped that to 20%. What can I do to combat the high nitrate levels? I have a lot of filter media in my system, and have heard recently that that just houses nitrate. I have a sponge over my filter intake to save my anemone from getting sucked up, as well as the Pengiun 125 filter media and attached Biowheel. Should I be getting rid of this stuff?

 

Stocking:

I've finally realized my stocking limitations, in that I will likely only be able to keep one fish (however I'd love to be able to have two). I originally had a damsel to cycle my system, then returned him for the clowns. After loosing them I'm pretty much closing the door on the cute perculas as I can't afford $50 in the event that I kill another pair (not to mention, that it I don't like killing fish). Should I be keeping something smaller and more robust, like a damsel or wrasse? I would need something that likes cave cover, as the clowns certainly did not and were hence overcrowded. I'm completely open for suggestions.

 

Thanks to all that toughed through my long windedness, and a BIG thanks in advance to those who are able to offer up some much needed advice.

 

Cheers!

[Dingo]

To reduce Nitrate:

 

1) No more fish until you get it fixed.

2) Get rid of the Biowheel as it has no de-nitrating properties. Let your rock do the job.

3) Reduce your feeding. Your cleanup crew should be able to get most of what they need from your rock.

4) Only use ro/di water or distilled water for water changes. Nitrate and Phosphate are often present in tap water.

5) Step up your water changes to dilute the nitrate already in your tank.

 

When you do get a fish, you must only feed him lightly and he must be small because decomposing food and fish waste are the fuel for Nitrates.