Is a biofilter (like Seachem's Matrix) really necessary?

[Sasha]

I have a 37 gallon discus-only, non-planted tank that houses my 4 juvies. I have a Penguin BioWheel 200 HOB (Hang on Back) filter with 2 filter cartridges installed. (I have removed the carbon from the manufacturer's filter cartridges based on researching through many seemingly-trustworthy internet forums. I'm still not sure this is the best course of action, but that perhaps warrants a separate discussion?? I'm not sure if the chemical and bio filtering processes might be related?) I have a sponge at the bottom of the filter's intake tube, and I have about 1" of gravel.

Is it necessary to also have an additional form of "biofilter" media such as Seachem's Matrix stone to optimize the health of my tank? Is it worth the investment in that product, or is there another one that is generally preferred? Or will the colonies in the gravel and other surfaces eventually grow to handle the bioload?

(As an aside, I have been struggling with a Nitrite spike over the last 3 days. My tank was fully cycled before adding my 4 juvies, but evidently the nitrifying bacteria was not sufficient to support the discus bioload. I got my fish on Feb 19th, and all water parameters were great for 2 weeks, then the spike. The week prior I had removed about 2/3rds of the gravel to allow easier cleanings. Wonder if removing the gravel had that dramatic of an impact on the bacteria counts to have caused the spike, or if it would have happened anyway??? I am treating with Prime and doing 25-30% water changes 1x-2x per day. Fish are swimming normally, eating, and occassionally bickering :-))

Will adding Matrix help either correct this problem or minimize the chance that it will happen again? Thank you for your help!

[Darrell Ward]

Yeah, it sounds like you're experiencing a "mini cycle". This means the addition of your juvies overwhelmed your bio filter. Adding more bio media will do nothing until the bacteria levels rise high enough to meet your fish load. Matrix is a very good bio media however. I've used "Pond Matrix" for years. (larger pieces of matrix) Adding extra media will help after you finish cycling. You could also use sponge material instead. The carbon cartridges won't really help with anything if you change water frequently, although the material holding the carbon could harbor some bacteria. You are doing the right thing by doing daily water changes, and dosing Prime. It will take a little more time, but when your tank balances out, your nitrites will drop to zero, and your nitrates will start to climb.

[Bud]

Hey, new to discus but a seasoned aquarist,and removing the gravel definately reduced bacteria levels.Prime does detoxify nitrite & nitrate and gets rid ammonia. You could try some bacterial additives for a jump start,and keep on the water changes(testing to see if theyre substantial enough)

[ericatdallas]

It's not -ESSENTIAL- you can do just fine without it as I do and many others do.

I did do something similar to you. I transported my discus from a gravel planted tank to a BB 75G tank that was NOT cycled (so actually worse than what you did). I just did 33-50% WC twice a day and used a filter from the other tank. I did have a mini-spike but things are fine now. The discus didn't get sick, they continued to grow, and they were happy and ate a lot.

In fact, I didn't experience any problems until I became inconsistent with my water changes and feeding schedule due to my own limited and irregular schedule. Today is my third day without changing water (actually the longest I've gone since getting discus). But as of this morning they still seem happy. I limited the feedings and gave them smaller portions so the water hasn't gone as out of hand as it normally might with normal feedings.

[Sasha]

Thank you for your responses! It's wonderful to have the support of others who may have shared a similar experience.