Tropical Fish Forums

[Burbank]

I have a 20 gallon fresh water aquarium. I know the rule re: 20 linear inches of fish for a 20 gallon aquarium. My swordtails have had about 7 babies and my nitrAte is just a tad high. All other tests look good.

Anyway, my 20 gallon aquarium came with a TopFin 20 filter. I'm concerned that it's not filtering enough water so I have replaced it with a Bio Wheel filtration system which is rated to treat "up to 50 gallon aquariums". The Bio Wheel filter can filter up to 200 gallons per hour of water.

My questions are: Is 200 GPH on a 20 gallon tank overkill?

[Angela G.]

Basically there is no such thing as too much filtration...however there is such a thing as too much current caused by your filtration. You don't want the fish being pushed all around the tank. If the current doesn't seem to bother them in any way it should be fine.

Also nitrate isn't as harmful to fish as nitrite...if you have too much nitrate you just need to do a partial water change and problem solved. Nitrate always builds up in tanks over time as it is the end product of the nitrogen cycle. If you mean nitrite then your tank is probably cycling from the increased bioload.

[DF Bobo]

that's pretty much true, that the current is the real thing you should be concerned about. besides, the bio-wheel filters are relatively low in current strength, so I don't think that will be a big problem. you should also know that the 1 inch per gallon rule is pretty much junk. here's why
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[Burbank]

Thanks for the quick reply. The current created by the filter seems fine. I don't know why the nitrates are high. I've been wondering if it's too much food not getting eaten but we try to avoid that.

Using Mardel 5 in 1 test strips:

Nitrates seem to be close to 80 ppm (low end of stress area)
Nitrite is close to 0
Total hardness is between 120 and 250
Total Alkalinity/buffering capacity 120-180
pH about 7

The fish (tetras, swordtails, guppies, and two algae eaters) all seem happy. I like this 200 GPH bio wheel because it grabs its water from near the bottom and at the middle point of the tank. I'm glad to hear I'm not over-filtering.

Dave

[Burbank]

And I keep forgetting to mention that I perform a 20-25% water change once every 7-14 days.

Dave

[fishlover888]

How many fish in the tank and how often/how much/what do you feed them?

These are the major factors for high nitrates reading.

Adding filter capacity will not help you reduce nitrates. Only water changes will do that for you. Some plants may do that too but you need lots of them in order to bring down the nitrates.
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125 g discus tank 13 discus, 5 Sterbai cory, 3 clown loaches, 1 Albino BN pH 6.3 50% WC x2/wk
2 g nano tank 3 Danio, pH 7.6 80% WC/ 2 days

[Burbank]

>> How many fish in the tank and how often/how much/what do you feed them?

4 flame tetras
3 cardinal tetras
3 neon tetras
3 swordtails
2 algae eaters (small ones, can't recall name)
3 fancy guppies
About 5-7 baby swordtails

They are fed a pinch of TetraMin flakes in the morning and another pinch in the evening. Generally, we try to give them what they'll eat within 2 minutes.

>> Some plants may do that too but you need lots of them in order to bring down the nitrates.

There are 4 live plants in the aquarium.

Thanks,

Dave

[fishlover888]

Your nitrates reading is kind of high. I would first start with 7 day water changes instead of 7 - 14 days. Also, change more water 40% instead of 20 - 25%.

See if that will bring down the nitrates. I do think there are bit too many fish in the 20 g tank. I know these are small fish, so is the tank. The only way you can overlaoding a tank is up the water changes. I would not do that but it can be done. I know some discus people do 100% daily water changes.

200 gph is fine with 20 g tank BTW. The general rule is 5 to 10 times of the tank size for filter turn over rate. In your case it is 200g so you should be fine.
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125 g discus tank 13 discus, 5 Sterbai cory, 3 clown loaches, 1 Albino BN pH 6.3 50% WC x2/wk
2 g nano tank 3 Danio, pH 7.6 80% WC/ 2 days