Q.    In the last 4 years I've had 10-15 Dempsy's, Oscars and Red Devils. Last week the first Dempsy I ever had died which left me with 1 Dempsy, 2 large sucker fish and a very large psycho Bala Shark.

I was at my local pet store looking at fish when I saw a tank full of African Cichlids. Long story short, I bought 4 of them (not sure what kind).

I also bought a water test kit (never tested it in the past 4 years) and here are my results:

Nitrate = 100
Nitrite = 0
Hardness - 300
Alkalinity = 240
PH = 8.2

From what the kit says, my new little guys are in danger.

My tank is 90g with 2 Fluval 303 canister filters, a powerhead, a heater, air stone and air tube (curtain). The bottom is covered by 2" deep of small rocks, and I have a few decorations for hiding(plastic sunkin ship, half log and a few rocks).

They're eating good and seem to be getting along for the most part and I did a 1/3 water change after I tested the water. (PH was originally 7.4, now 8.4 after adding 1/2 cup of baking powder)


Any help, advice, suggestions of any kind would be greatly appreciated.

Thanks!

A.     Nitrate is constantly being produced in fresh water systems. It is the end product of the nitrogen cycle (i.e. the bacterial breakdown of wastes). Nitrate is only dangerous in very high concentrations for most fresh water fish. Nitrates are reduced through regular (weekly) water changes and to some (minor at best) extent by plant growth.

It is important to keep your filters clean (the mechanical sections that is -- floss, etc.) because waste builds up in the filter and must be nitrified (broken down) by the beneficial bacteria in the filter. The more waste, the more nitirification, and the more nitrates in the system. Simply put, just because you can't see it in the tank doesn't mean it's out of the system (it's still in the filter).

Reducing the waste load (less fish, less feeding, or prompt removal of dirty filter media) results in reduced nitrate production. The suggestion to add one or two hang on back filters is a good one since they are easily cleaned (look around this site for DIY cartridge ideas to keep costs low). As an alternative, you could just affix a sponge to the intakes of the canisters. That "prefilter" could be rinsed off every couple of days and the mechanical media in the canisters could be changed every other week or so.

I would also suggest the following:

1. Remove the "small rocks" serving as gravel in the tank. They collect waste easily. Replace them with a thin layer of some form of African Cichlid Sand, just 1/2" or so. The sand keeps waste on top, and it will buffer the water in the system.
2. Don't worry about messing with the pH, etc. The Cichlid sand will help keep your pH up, and fish suffer more from swinging the pH back and forth than they benefit from a specific pH reading. Besides, most fish from the store were bred and raised in water much more neutral than that in which their wild cousins live.

Oh yeah:
3. Enjoy your tank!

Follow-up Q. 

Thanks, chc.

You wrote "you could just affix a sponge to the intakes of the canisters".

Do you mean to the actual tubes that are in the water or do you mean inside the canister itself?
If you were referring to the tubes, wouldn't it restrict the water flow into the canisters?
If you meant in the canister itself, the first part of the 3 stage canisters is 2 foam sponges, then charcoal, then media. So wouldn't those foam sponges serve the same purpose?

I've also read on some posts that charcoal is not necessary. Is this true? If it isn't, what sould I use in that stage of the filter instead? (more media?).

As far as cleaning the filters, I usually just "rinse" each stage, not "replace" each so that I don't lose the beneficial bacteria. Is this the right thing to do?

I'll take your advice in the Cichlid sand and remove the rocks. I used rocks because I thought sand would get stirred up and float around the tank.

Please excuse my lack of knowledge.

A.   The sponge goes on the end of the intake tube (in the aquarium itself). The idea is to keep solid waste from getting into the canister. Just get a replacement sponge for an Aquaclear filter, cut a little slot or hole in it, and rubber band it to the tube. The pores of the sponge are large enough to let water pass as long as you rinse it out regularly.

Carbon is unnecessary in a healthy tank that gets plenty of water changes and other good care. It actually can be dangerous as it eventually may release chemicals back into the system if it isn't changed out frequently. Also, it ca become heavily colonized by beneficial bacteria -- not a problem until you replace the carbon and thusly eliminate a large part of your biological capability (but that's an issue with any porous media).

If you want some "chemical insurance" in your system I suggest either PolyFilter (comes in a white pad form) or Chemi-Pure (granular). Neither has the drawbacks of carbon.

Otherwise, just use more sponge in your canisters in place of the carbon. If you have many layers of sponges in a filter, you can aggressively rinse one at a time under plain tap water with no fear of damaging your bio-filter. As long as the others are undisturbed (other than perhaps shuffling their order so the clean sponge is farthest upstream), you'll have plenty of bio-capability. If you do not have plenty of sponges untouched in the filter, just rinse the dirty ones in a bucket of tank water or dechlorinated tap water (chlorine may kill your bacteria). What you're looking for is the most possible biological media possible in your filters (sponges in your case) and the least amount of particulate waste clogging them (hence a prefilter on the intake and, perhaps, a frequently rinsed coarse sponge as the first layer in the canister).

You shouldn't have to replace sponges for quite a long time (once they no longer fit snuggly and allow water to bypass them).

As for sand, if you use one of the commercial brands that buffers the water (try Carib Sea's Sahara Sand or their Eco-Complete Cichlid Sand which is packed wet and has beneficial bacteria in the bag), your pH will stabilize, and the sand won't float around. Prefilters on any pump or filter intakes gives you more margin for error too. Some people use cheap play sand  (after much, and I mean MUCH, rinsing) or pool grade sand (much less rinsing) with good results, but you will not get the buffering effects that you may want for an African or Central American tank. Besides, you only need a thin layer, and it's worth the investment. Try about three bags in the 90 gallon; four maybe.

By the way; no need for apologies........ There was a time when I would have liked to be as aware as you are!

- chc