Nitrates that simply refuse to go down?

[Sjasmin888]

I have two 20 gallon tank setups, one heavily planted, the other lightly planted. They are both slightly overstocked, but cycled. I do water changes of around 30% every 2-3 days but recently my nitrates have just refused to go down properly. I have started doing water changes of around 50% the last few days, but simply can not get the nitrates below 30ppm. I have tested my tap water, and even let it sit for almost 10 minutes, checking the color frequently, but it doesn't have nitrate. What on earth is going on here?

 

[Autumnsky]

What are the filters on the tanks and what media do you use?

Do you have any live plants?

 

[Autumnsky]

What is the filter for each tank and what is the media in the filters?

Do you have any live plants?

What is Overstocked look like in the tanks?

Have you ever tried a binding resin type product?
Welcome to API Fishcare: NITRA-ZORB®

 

[Sjasmin888]

Tetra Whisper 30's with carbon filters. One tank is heavily planted and the other is lightly planted. Strangely it's the heavily planted tank giving me the most issue despite the fact that it's actually more lightly stocked fish wise.

 

[Sjasmin888]

The heavily planted tank has two rainbow sharks(3 inches), two kribensis(2 1/2 inches), 6 zebra danios, and 3 dwarf blue rams.
The lightly planted tank has 19 white cloud mountain minnows, 3 hillstream loaches, and 5 neon tetras.

 

[Autumnsky]

Both tanks are over stocked and under filtered, and the fish need an upgraded tank asap!

I would keep an eye open for a 55G-75G for the sharks. Aggression will increase as they mature.

As for the nitrate, what about vac'ing? Do you do anything to get any muck out of hte substrate. Usually the heavily planted tanks don't get vac'd hardly at all, but it would likely help.

What about food, changing feeding can also help.

What kind of food(s) are you using? Then also you might reduce the amount and consider different feeding times, like feeding bottom feeders at night and the other fish in the AM. Cut back quantity and change to am/pm.

I will suggest Hikari foods Sinking Bottom Feeder wafers, and micro wafers for the smaller types, like WCMM and Tetras. It seems they break down slowly and do not seem to raise Nitrate like flake (or foods with lots of flour/grain fillers) or some high quality more protein dense foods.

 

[Sjasmin888]

I gravel vac with every water change. I am fully aware that the sharks will need to be separated when they start showing signs of aggression and happen to have a friend willing to take one. As far as feeding goes, I feed twice a day. The tank with cichlids gets a small amount of flake food around 12 pm when I get up. They get 1 frozen cube of a mostly veggie based frozen food and 6-8 cobalt shrimp pellets around 12 am before I go to bed. The minnow tank gets a small amount of flake food around 12 pm, and either more flake food or a cube of frozen cyclops at 12 am. I think anything fully sinking would be too stressful for the minnows because most of the bottom level has a reasonably strong current for the hillstreams and aiming the food directly into the calm areas wold be virtually impossible. I kinda want to know how I'm under filtering 20 gallon tanks with filters meant for 30 gallons though...

 

[Sjasmin888]

I also just realized I failed to mention my ADF and banjo cat in the cichlids tank. I make sure to add the shrimp pellets because I'm not 100% positive the banjo eats the other food as I only see him when I dig around in the tank. The veggie based frozen food is for the Kribensis, as they started munching on my more delicate plants when I got them. I monitor aggression levels in my tanks rather religiously and occasionally reorganize the decor to confuse territorial lines. All of my fish actually seem to be pretty healthy. Great appetites, healthy foraging habits, better color by the day, and constant exploration. There are no signs of unhappiness or poor health whatsoever in my tanks. I'm only really super worried about the nitrates because my gh and ph aren't exactly optimal (I've ordered some things to handle that, should have tomorrow). I'm just trying to be extra careful about extra stress.

 

[Autumnsky]

Off to bed now, short answer is need more filtration for the amount of bioload. Filters reduce there gph as the filter media ages and water doesn't pass through as often, reducing flow which can be good to allow more time to be in contact with the BB ammonia converting processing, but not as good because you do not turn over as much water to help clean it.

Just trying to help fix your problem, why I brought thouse things up. I also have pushed the envelope for stocking and sometimes you might be able to manage it and other times it will get out of control. Glad to know you are monitoring.

Maybe if you can add an additional filter pad into the unit to add additional room for more BB to colonize you will be better off.

Run your stocking levels on aqadvisor. You can try different filters and tank sizes to see what your optimum levels from fish to filters to gallons.

 

[Sjasmin888]

Aqadvisor..I've never heard of it, but I'll definitely check it out thank you for your assistance. I may add another filter to each tank or see about getting a small sump for the problem tank. Small apartment, so I'm kind of limited on space :/

 

[flchamp89]

What alot of people forget is that when overstocked. Its not just the fish its the food going into feed them.

 

[Autumnsky]

Try the Hikari Sinking Bottom Feeder wafers instead of shrimp pellets. Shrimp = Ammonia = Nitrates. You can break them into chunks, they are already small but that way the bottom feeders can get them and not need to share one.

 

[BBradbury]

Sj...

A nitrate reading of 30 isn't bad. Most fish won't even notice this. Nitrates have to reach the 80 to 100 ppm range and remain constant for several days, before fish you get at the local pet store are negatively affected. Keep the water chemistry stable by removing and replacing most of the water every few days. This all you need to do.

B