Nitrate Problem

[Terra]

Hi Guys

I have two tanks that were purchased from the same gentleman. Upon water testing I've found ammonia and nitrites to be practically zero but nitrates are off the charts...literally. I do 30-50% water changes weekly and have even tried a massive dilution water change (which brought the levels down for about a day), cleaned the filter (which was disgusting) and still my nitrate levels are so high as to be unreadable. My fish are dying, one by one. Perfectly healthy (seemingly) the night before and when I wake up, they're dead. Usually one every 4 days or so. I can't think of anything else to cause this other than the high nitrate levels. I think my last resort is to tear the tanks apart, rinse the gravel really well, change 70% of the water and add a tonne of cycle and that stuff that breaks down junk in the tank. Does this sound like a good plan? I know I run the risk of cycling my tank again, and I'd be happy to hear any alternative approaches. Thoughts?? I don't want to keep scooping my fishies out of the tank!!

[jzz30tt]

How is the tank filtered?

How clean is the gravel?

Any ornaments that haven't been moved in a long time?

How good/fresh is the test kit you are using?

Nitrates are not a substance that comes from nowhere. It always has a source. The usual culprits are a buildup of waste in the filter media, gravel or in and under ornaments.

Also what is the bio load like? What kind of gallonage is the tank and what size and quantity of fish are in there?

Need more of this info to help out.

[Terra]

The tank is filtered with a Fluval 203 canister filter than just had the foam and most of the media replaced as it was so disgusting.

I'm thinking the gravel is the culprit as it came with the tank and one can only guess how frequently the previous owner vacuumed it.

The test I use is brand new, that gives me appropriate results with my other 55g tank that is not affected by this nitrate problem.

Right now there are way too many fish in the tank. I have another waiting to be started. The current (affected) tanks are a 20g with probably 40+ fish in it (this was not my doing, the tank came to me this way- I plan on taking at least half of these out and putting them in the new tank) and a 30g with 10 fish in it.

Hope this helps, and thank you for the reply!

[jzz30tt]

Do you have a gravel vac? If so it's time to use it. The gravel is likely the nitrate factory right now. You will have a lot of nitrate production based off your bioload to begin with let alone not knowing what the status of detritus in the gravel is right now. Do you have any prime? They do claim to be able to detoxify nitrate but the water changes you've been doing are the best thing for reducing nitrate. Next is to remove that source of nitrates.

It's a shame to see some of the tanks you find for sale.

What media was all replaced in the filter? You might want to get used to rinsing them well in tank water vs replacing them. Maintain your bacteria colonization and maintain a stable tank.

Wish you the best in getting things dealt with. Let us know how badly gunked up the gravel is at it's the most likely source of your nitrate levels.

[Terra]

I definitely have a gravel vac and do vacuum the gravel every two weeks, but I don't think it hasn't really been stirred up for a long time. I'm afraid to see what I'll find! :S

My first attempt to lower the levels was at the filter level. I rinsed 2 out of 3 foam filter pads in aquarium water along with the large first filter blocks. There was no biomax or any other media really other than carbon + peat. I threw those out and but in some biomax, clearmax (claims to remove nitrate among other things), ammonia remover and carbon. I thought for sure this would help but to no avail.

My plan is to remove 70-80% of the water, wash half the rock in aquarium water and the other half in tap water. Also like I said half the fish will be moved. I'm hoping this will do the trick without cycling my aquariums.

I'll be sure to post what atrocities I come across in the gravel and the results of my mission! Wish me luck!

[jzz30tt]

Sure thing, make sure that gravel vac gets right down to the bottom and gets everything out. It's sure to be a nitrate factory as was the filter. Regular maintenance will maintain a stable and long term tank. GOOD LUCK!!!

[Kronosdelsol]

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Edited October 2, 2010 by Kronosdelsol

[SourceAquatics]

why not just remove the gravel, do a good cleaning on the tank and gravel (large water change) and put the gravel back in once you have removed the extra fish.

Might not look as pretty for a few days but may help resolve your issue.

I use a fish net to take my gravel out a little bit at a time.

[Kronosdelsol]

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Edited October 2, 2010 by Kronosdelsol

[werner]

Sounds like Old Tank Syndrome. Go easy on the water changes to reduce the nitrates- large, sudden changes will shock and kill the fish.

[Terra]

Hi everyone,

Thanks so much your all your suggestions. I think I sort of combined them all into an effective process.

A little update on the nitrate situation. My 30g and 20g were the ones affected.

I attacked the 20g one last night. I didn't move the fish but took out pretty much all the gravel and vacuumed all the sludge out of the bottom. Buried in the 6in pile of gravel in this short tank was an old plant pot still filled with mineral wool, several 2in thick pieces of slate and countless dead plant leaves. The dirt in the gravel was so thick I thought it was soil at first!

Upon water testing this morning my nitrates were at 5!!!!! And all my other figures were perfect also. This is so amazing to know my fish aren't suffering anymore.

Now to tackle the 30g... I'll let you know how that one goes too!

Thanks again,

Terra

[jzz30tt]

Perfect, I thought that substrate would be bad.

[Terra]

Ok,

So I did the 30g yesterday. To avoid totally stressing my black ghost knife and red tail shark I thought just stirring up and vacuuming the gravel really well, along with a 50% water change would do the trick.

Upon water testing 3hrs later my nitrates were still off the charts. So, I decided to take the gravel out completely similar to the 20g. I'm glad I did as I found several old elastic bands, tonnes of dirt and dead plants (!) in there. I nearly killed my bgk when his slate cave collapsed, and I've only ever seen my red tail shark so grey when we got him. Poor things. Anyway, I also performed another 20% water change at that time.

Upon testing today I think my nitrates are between 50 and 110. Still way too high!! AND, my 20g nitrates crept back up to 10 from 5 in one day with a 20% water change yesterday! I'm getting very frustrated. What else could it be??? Do I just keep up with the 20% water change daily? When will it ever stop?!?!

[Kronosdelsol]

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Edited October 2, 2010 by Kronosdelsol

[Ishkabod]

It sounds like in the 20 gallon you have too many fish still (maybe) and in the 30 gallon you said you had stirred up the gravel before desideing to remove it? You might want to check your filters again as cleaning like this does tend to send the debris to pile into the filter again and create another factory situation and that could be the sourse of the problem this time. Also if you are feeding more than once a day cut back to once a day, Add PRIME and Stability (both from seachem) I've tried cycle in the past and it didn't work at all but stability for me has actally, independent of added bacteria from other tanks, completely cycled a tank of mine in about a week.

Good luck

L