Having Trouble Reducing High Nitrates!

Hi, I'm new to this forum. I'm fairly new to fish keeping to. So I have a 10 gallon tank that was cycled before I put fish in. I have a sponge filter and a power filter that hangs on the side. I have 4 adult mollys and 5 baby's that are in an attachable net on the side until theyre old enought to go in another tank. My problem is that my nitrates have gone up and I can't seem to reduce them. I've done multiple vaccumings and partial water changes but they sTay the same at around 30ppm. I haven't lost any fish but I'd like to know why they aren't going down. Please forgive the lack of knowledge but like I said I'm new to this. I don't want to stress or hurt my fish so any help would be appreciated.

 

It’s because you have all those Mollies in the 10, you’re overstocked and it’s causing too much waste. But not to worry, we’ve all been there. You live and learn.

I’d suggest upgrading the tank.

 

if your nitrates are that high I recommend like a 50% water change. I had this problem. also remember to vac under decorations and or decorations you put down after your tank was established. just what I did and they went down

edit: and what aquaticJ said

 

I wouldn´t say 4 mollies in a 10 is overstocked at all! Even if you go by the most basic rule (inch per gallon).
I think the problem could be elsewhere. Maybe you are over feeding. Try to do deep gravel vacuumings if you don't have soil or anything under the gravel. Like Nick said, don't forget to clean under the decor were waste tends to build up. Try doing 2x 50% water changes a week and nitrates should go back to normal. Keep this in mind: underfeeding is better than over feeding with fish.

 

4 mollies in a 10 with some babies is no where near overstocked. This indicates overfeeding and decay in the substrate as a likely root cause. Just the fact that you water change and don't see a difference indicates the problem is caused by the substrate.

 

For starters, 30ppm isn't really high. If you're bioload is producing 30ppm per DAY, then you have a problem. 4 adult mollies is pushing it for a 10 gallon, add to that the babies and all the food, you're overstocked. Either get rid of some of the mollies or plan on doing 50% water changes every few days. But if you're doing a 50% water change every Sunday and you're at 30ppm, that's nothing to worry about.

 

Absolutely complete non sense. Where are anyone's scientific numbers to prove 4 mollies and babies cause 30 ppm day nitrates?

 

I recommend getting a small cutting of pothos and putting it on top of filter.

 

Absolutely complete non sense. Where are anyone's scientific numbers to prove 4 mollies and babies cause 30 ppm day nitrates?

You need to read what I wrote. I said IF his tank is producing 30ppm. As in day 1 he is at zero, day 2 he is at 30ppm, THEN he has a problem.

And if you want to get into the "science" of it, you could have NO fish in the tank and produce 30ppm nitrates a day IF you were dumping in too much food. Its pretty basic stuff. 9 fish with BIG bioloads in a small tank plus overfeeding can get out of control fast.

 

Nobody has suggested that it might be your tap water. Have you tested your tap water for nitrate OP? Some people have it right from the start.

 

Can add some live plants too!

 

Live plants in the tank as well as adding more filtration like bio media and sponges will help. The big thing is more plants, they'll eat up the nitrates.

 

Nobody has suggested that it might be your tap water. Have you tested your tap water for nitrate OP? Some people have it right from the start.

That is a very good point! Highly likely too, since he is not overstocked and has been doing frequent w/c´s. Unless he is over feeding, his tap could be the root of his problems.

I can hardly imagine how mollies would be considered "BIG bioloads." Sure could eat a lot, most fish do. These fish tend be only 2 inches males MAX 3 inches in most ppls tanks. That is a small stomach for them to be considered over stocking a 10g. I think 4 mollies aren't overstocked in a 10, sure. . .the babies are pushing it, but they ARE babies, so they´re not polluting much at all yet. Unless he is overfeeding, the problem lies in his tap, not in his stock.

 

So I removed the babies and put them in another tank. Now there are only 4 fish. I did a partial water change, and vaccumed, and the nitrates did go down but only to around 20ppm. Still enough to stress? I was feeding twice a day but now I'm going to once a day. I do have plants. I'm worried maybe I vaccumed to much, which removed to much of the beneficial bacteria. I did test my tap water and it's at 0. After reading everybody's posts, I'm thinking it could be a combination of overfeeding and to many fish. My last question, how long after doing all this should the nitrates start to go down?

 

Nate-don't forget that half a flake a day is enough for a Neon Tetra and four and a half flakes a day are enough for a small (8g) Goldfish.

I would find 20-30ppm nitrate acceptable in your tank but you are right to try to keep it as low as you can.

What's your ammonia level?

 

About .25 ppm.

 

The 10 gallon is overstocked. Mollies need a minimum of a 20h or 20l for space. A 15 gallon would be pushing it. But 4 mollies in a 10 gallon is definitely overstocked. They need more room to swim and they are huge waste machines. You'll need to do water changes 2-3 times a week to stay ahead. Start looking for a larger tank if you want to keep them. Then you can keep the 10 gallon as a backup quarantine/hospital tank.

 

I wouldn´t say 4 mollies in a 10 is overstocked at all! Even if you go by the most basic rule (inch per gallon).

A single molly needs 30 gallons minimum. By the inch per gallon rule the tank is very overstocked considering most mollies get to around 4".

 

Most common mollies sold in stores average size is 2.5" for the females and the males are about 2" adult size. 4" is the max not the average unless you have sailfins.

 

A single molly needs the same amount of space as an adult angelfish! (30g)
Ok ok.
This got funny fast!

Size of mollies vary from 2-4 in depending on what specie. It all depends what specie s/he has. We can't just assume s/he has the biggest. 4x 2-3 in mollies will be fine in a 10 as long as s/he does not over feed and does wkly maintenance. I wouldn´t do more than that. 20ppm nitrates isn't dangerous. Lower ppms will always be benefecial unless you have plants, but 20 ppm is not dangerous. 4 mollies will live a long healthy life in a 10g.

He won't need to do tri-wkly w/cs if he does not over feed. Space-wise, there are some tens that are 2ft long. All depends which he has. What are your dimensions OP?