Can algae cause high nitrates?

[zero2dash]

Ok, here's my problem.
I have high nitrates (160 ppm) that I've had for about a month to month and a half now. Initially, I didn't know much of anything about what to do about it.

I started out by doing a gravel vacuum and a 35% (in total including what the vacuum took out) water change. I waited another 2 weeks before doing another 35% water change and after testing my water again the other day, it's still 160 ppm. I don't have a lot of fish and there's no way that there's this much fish waste freshly added that would cause this again due to a high fish waste count.

I read somewhere that it could be my tap water so I tested that and came up with nothing (tap water tested out nitrate = 0). I recently changed the filter media with brand new ones so it's not that.

The only things I can think of is that it's either a) my fake plants, b) fake rocks/driftwood, c) the algae on both, or d) a combination of them all.

Can algae cause you to have high nitrates? I know nitrates can cause algae outbreaks, but does it work vice-versa? I'm considering removing everything from the tank (all the fake plants, rocks, driftwood) and waiting a week and re-testing, and possibly even removing all the substrate even.

I'm at a loss...any ideas?
I want to buy a severum to (eventually) be the lone inhabitant of the tank (you know, one huge fish instead of lots of smaller ones) but almost all the fish I have right now seem to have hole in the head disease (their heads sorta have "craters" in them like they had zits when they were kids or something) and I don't want to put a fresh healthy fish in this tank with all these nitrates I can't get rid of.

I've considered buying the chemical stuff at pet stores to lower nitrates but didn't know if chemicals were the way to go...?
Again I've done roughly a 70% total water change over the last month with this tank and I'm wondering what to do at this point.
I'm also planning on buying an Emperor filter within the next week or two; I don't know how well my filter is doing anymore and I'm wondering if that's another reason my water quality is so (literally) crappy.

TIA everyone.

 

[aqh88]

Algae appears when there are high nitrates because it has a large food source. Unless you suddenly killed a bunch of algae with algae chemicals it shouldn't add any nitrates. It can use up oxygen though but otherwise it should be helping you. Do a 25% water change daily for the next few days and see if your nitrates test lower. Don't do a gravel vac on all of those days or you could destroy too much bacteria. The driftwood could be the cause. I've bought driftwood online and added it to a 20g tank with 2 small 1" fish and ended up with 5ppm ammonia in a day. Even after that tank cycled it was a nightmare until I removed the driftwood. Another thing.. Did you shake the nitrate bottles? I've forgotten to do that before and gotten surprisingly high readings.

 

[Devilishturtles]

How many fish do you have and in what size tank? Doing a WC every two weeks may be your problem, especially if you have a lot of fish, overfeed, or underfilter your tank. What filter do you have now, and what is the gph reading on it?

Do some daily pwc's for a while until you get your nitrate down. 160 ppm is dangerous.

 

[tkos]

A 35% water change will hardley dent 160ppm of nitrates. And waiting 2 weeks means that it has plenty of time to shoot back up. Chances are you are overfeeding your fish, so there is plenty of excess food in the tank which will form nitrates. Fish can survive high nitrate levels for awhile but eventually they will get sick. As aqh88 says start doing 25% water changes daily (don't shock them with a huge change right now). When the nitrate levels get down to 20-30ppm max then start to slow down the water changes to keep the levels around 20ppm or so. This usually means 30-50% water changes weekly.

Doing a gravel vac each day won't hurt the bcateria, it is very strongly attached to the surfaces it lives on and will take more than a gravel vac to harm them.

Also it could be time to clean the filter. Rinsing older media can prolong its life (I rinse in old dechlorinated tank water) and usually every few months it is a good idea to actually clean the filter (a fresh toothbrush is a good idea). Scum can build up inside the filter chambers.

 

[malkore]

all good advice so far. only large amounts of dead, decaying algae would create nitrates...otherwise, the algae is actually using nitrates for food.

My aim on all of my tanks is a weekly 35-50% water change. When I miss a week, I try to do a 65-75% water change. Some of my tanks are heavily stocked...but regardless, the fish are all healthy, I don't have algae problems (I have high light, planted tanks which are very prone to algae), and I often have to add nitrate to keep plants healthy.

step up the water changes to 50%, and do one every other day for the next week and see if your nitrates don't fall. If it's 160ppm today, a 50% wc should put it at 80ppm tomorrow, then 40ppm after the next w/c, etc.

 

[zero2dash]

Another thing.. Did you shake the nitrate bottles? I've forgotten to do that before and gotten surprisingly high readings.

Yes, I followed the directions on them and shook them for the time it said to. (Put in 10 drops of bottle 1, mix good, shake bottle 2 for 30 seconds, add 10 drops of bottle 2, cap vial and shake for 1 min then wait 5 mins for results, etc.) I did all that.

How many fish do you have and in what size tank? Doing a WC every two weeks may be your problem, especially if you have a lot of fish, overfeed, or underfilter your tank. What filter do you have now, and what is the gph reading on it?

Do some daily pwc's for a while until you get your nitrate down. 160 ppm is dangerous.

I have 11 fish in a 55 gal tank.
4 blue gourami
1 gold gourami
3 pink bloated gourami (flat and round like discus, basically)
2 golden chinese algae eaters (not making a dent)
1 pleco

In total I've probably got 25-30" of fish inches for my tank so I'm not overcrowded. And I feed them usually only once a day; if I feed them twice a day I skip the following day. I think I underfeed them, truthfully.
As for the filter, I have a Whisper 30-60.
http://tetra-fish.com/Catalog/product.aspx?id=577
No mention of gph on their website.
A lot of people frown upon Tetra products but I've had 100% luck and satisfaction in Whisper filters for over 10 years. (Again though, I'm planning on buying an Emperor soon, if not *two*.)

A 35% water change will hardley dent 160ppm of nitrates. And waiting 2 weeks means that it has plenty of time to shoot back up. Chances are you are overfeeding your fish, so there is plenty of excess food in the tank which will form nitrates. Fish can survive high nitrate levels for awhile but eventually they will get sick. As aqh88 says start doing 25% water changes daily (don't shock them with a huge change right now). When the nitrate levels get down to 20-30ppm max then start to slow down the water changes to keep the levels around 20ppm or so. This usually means 30-50% water changes weekly.

Doing a gravel vac each day won't hurt the bcateria, it is very strongly attached to the surfaces it lives on and will take more than a gravel vac to harm them.

Also it could be time to clean the filter. Rinsing older media can prolong its life (I rinse in old dechlorinated tank water) and usually every few months it is a good idea to actually clean the filter (a fresh toothbrush is a good idea). Scum can build up inside the filter chambers.

I'll clean the filter tonight when I go to do another water change.
Which brings up the one question I have now...which should I do, a 25% change every day for a few days or a 50% water change every other day? (Or does it matter because I'm essentially doing the same amount over a 2 day period?)

Thanks again everyone.

 

[Guest]

I agree, i do weekly 20-50% water changes (depending on how dirty it is) and my nitrates never go over 40. I also have a lot of live plants, but as you can see i have a lot of fish too and a large bioload.

I would suggest doing a 25% water change daily, but a 50% every other day would be fine to. And keep testing your water until you get into a healthy range. Then you can keep up with regular weekly water changes.

 

[aqh88]

I think doing large water changes in this situation is going to drop the nitrates too fast. Also with doing water changes so spread out before there's a chance your tank water parameters could differ from your tap water. If I find a need to do a big water change I tend to do 2 small ones in the same day. Like change 25-30% fill the tank back up, wait an hour or 2, and then do another. That way the fish have time to acclimate to the difference in nitrates. Doing large water changes on tanks with high nitrates has killed plenty of fish. Every time I hear of someone doing a large water change on a tank that has only had water changes every other week or less and has over 100 nitrates it has ended in fish deaths by the next morning. Alot of those are people trying to help out someone elses fish and they end up killing them instead.

 

[zero2dash]

I think doing large water changes in this situation is going to drop the nitrates too fast. Also with doing water changes so spread out before there's a chance your tank water parameters could differ from your tap water. If I find a need to do a big water change I tend to do 2 small ones in the same day. Like change 25-30% fill the tank back up, wait an hour or 2, and then do another. That way the fish have time to acclimate to the difference in nitrates. Doing large water changes on tanks with high nitrates has killed plenty of fish. Every time I hear of someone doing a large water change on a tank that has only had water changes every other week or less and has over 100 nitrates it has ended in fish deaths by the next morning. Alot of those are people trying to help out someone elses fish and they end up killing them instead.

D'oh...
wish I would've seen this post last night before I did a water change/gravel vacuum. Ah well...

Last night I decided to do a (very) thorough gravel vacuum. I removed everything out of my tank (except the fish and gravel of course), and gravel vac'd like I've never gravel vac'd before. I'm sure there's a teeny bit of waste in there in crevaces I couldn't get to but otherwise - it is really really damn clean. In doing this I removed about 50% of the water; afterwards I removed a little more water and wound up with around 2/3 of the original water removed. I then filled it back up with fresh water, put in my dechlorinator, etc chemicals, and started the 2nd leg of the process.

I then thoroughly cleaned the filter; scrubbed out all the intake tubes and inside compartments, and freshly rinsed off the cartridges under clean tap water for about a minute each. I put everything back together, and started running the filter immediately. Most of my fish were sleeping during this time; I thought they were all dead but soon realized they were just sleeping. I also cleaned the hoods of the aquarium, and wiped off the heater and thermometer and put those back in (well, I cleaned and returned those a little while after the filter, actually).

I'm going to either a) clean off all my plants and decorations that were in the tank and put them back or b) I might get some real plants and go that route; I'm not sure which route I'm going to go at this point. I know planted would be a much better "healthy" choice for the aquarium, and I think I will most likely go that route. Every time I go to the pet store I see the real plants and just drool.

I put in two (algae free) decorations (2 small hollow plastic half logs) and let everything be for a few hours (not only to let the tank run but also to let the fish relax a little).

Now, one of my algae eaters did wind up dying. I checked the tank this morning and it looks like the rest of the fish are all still doing ok and I didn't lose any more. I'm sad to lose the fish that I did, but I'm glad that his friends all have a 200% cleaner home to live in. I hate to be so mean about this, but, the way I look at it - all the fish were suffering and/or slowly dying and I had to do something. The only thing I could think of doing was clean the hell out of it and if some die, then some die - but the ones that live will be much happier in the end. Hopefully I don't have any more losses, but if I do, well...I've learned my lesson.

I did feed them a little (very little) amount of food last night and all 5 of my regular sized gourami ate; the 3 bloated pink ones slept most of the night and my pleco just hung out on the glass (literally).

...

End result:
pH 7.0 (went up one)
Ammonia 10 (I think; went up from 0)
Nitrite 0
Nitrate 10
I'm ecstatic that I got my nitrates to go down finally.

I'll probably wait 2 days and then do another 25% and re-test and go from there. I'm sure by that point, I'll be a steady 10 at most (if not 5) on Nitrates and at that point (obviously) I'll start doing 25% weekly.

 

[tkos]

By the way you said before that you had so many inches of fish. Don't rely on that old system for stocking a tank. A pleco may end up being 18 inches long but is worth far more than 18 inches of neon tetras.

If it was your pleco that died I would suggest not getting another common one for your tank. Plecos are poop machines and can easily cause high nitrate levels. Dwarf plecos, SAE's and ottos are generally better tank cleaners and stay small and cleaner.

 

[Chriznat20]

Be sure you do not clean off the plants too good or you are going to kill all of your beneficial bacteria!! Also, be gentle on vacuuming the gravel too much, once or twice a month is enough!

I have the same problem, my nitrates have always been high. I have just about the same fish count as you, maybe 1 or 2 more and the same size tank, with the same power filter. I definately dont overfeed, sometimes I go 1-2 days between feedings, so I know your frustration.

I would HIGHLY recommend weekly 40-50% water changes, no less- no further apart. This will help your nitrate levels, it helped mine. Do this for good. If you skip a week, then do a 60-70% water change the weekafter but make sure to change the water weekly. Stop trying to go buck wild on trying the nitrates down, you are going to do more harm than good by killing off your bacteria.

Also I have the same setup (55 gallon) and I have 2 Whisper 30-60's and i also airate with a 6" bubble bar. Its a good idea to have some good bubbles breaking the surface of the water, it can help dissipate some of those bad chemcials in your tank

 

[greenmaji]

It looks like you lost all of your bacteria.. 8O
It would have been nice for someone to say somthing about not cleaning everything all at once! ouch.. I blame this on me.. I thought you were getting good responces so I failed to respond myself.. sorry about that
You might want to invest in some BioSperia or your going to be going through a new cycle..

 

[malkore]

Naw, I doubt much bacteria was lost. Bacteria sticks to the gravel, so it wasn't vacuum'd up.
As long as the tap water wasn't scalding hot, it probably didn't kill much bacteria on the filter media.
And the walls of the tank are coated with bacteria too.

I don't feel the whisper 30-60 is enough flow for a 55gallon. I'd look into replacing it with the biggest AquaClear hang on they make (Used to be called AC 500, I think it might be the AC 50 now), or the next size down, an AC 30, and run it with the whisper.

that or replace with a canister filter, like a Rena Filstar XP1 or XP2, and maybe a small power head (maxijet 600) at the opposite end of the filter return, just for added current.

I'm starting to find that my low current planted tanks don't do as well as the higher current ones...but obviously when injecting CO2, we don't want surface agitation, so powerheads become a lifesaver.

 

[tkos]

You have an ammonia test that goes to 10? That is super high. What sort of dechlorinator are you using and do you have chlorine or chloramine in your water. It is easy to find out if you have chloramine if you call your water department.

In the future clean the filter using old tank water that you remove. It is safer for the bacteria as the chlorine will kill some off. I doubt vacuuming each week will kill any bacteria and IMO should be done.

 

[greenmaji]

a retest of the ammonia and nitrite would be needed to make sure your bacteria is ok.. they both should be 0.

 

[zero2dash]

Man, another slew of questions to answer.

By the way you said before that you had so many inches of fish. Don't rely on that old system for stocking a tank. A pleco may end up being 18 inches long but is worth far more than 18 inches of neon tetras.

If it was your pleco that died I would suggest not getting another common one for your tank. Plecos are poop machines and can easily cause high nitrate levels. Dwarf plecos, SAE's and ottos are generally better tank cleaners and stay small and cleaner.

No, my pleco is fine; one of my golden chinese algae eaters died. As for the inch system, I just mentioned it to give an idea of how many fish I have (to dissuade the idea that I have an overstocked tank).

Be sure you do not clean off the plants too good or you are going to kill all of your beneficial bacteria!! Also, be gentle on vacuuming the gravel too much, once or twice a month is enough!

I have the same problem, my nitrates have always been high. I have just about the same fish count as you, maybe 1 or 2 more and the same size tank, with the same power filter. I definately dont overfeed, sometimes I go 1-2 days between feedings, so I know your frustration.

I would HIGHLY recommend weekly 40-50% water changes, no less- no further apart. This will help your nitrate levels, it helped mine. Do this for good. If you skip a week, then do a 60-70% water change the weekafter but make sure to change the water weekly. Stop trying to go buck wild on trying the nitrates down, you are going to do more harm than good by killing off your bacteria.

Also I have the same setup (55 gallon) and I have 2 Whisper 30-60's and i also airate with a 6" bubble bar. Its a good idea to have some good bubbles breaking the surface of the water, it can help dissipate some of those bad chemcials in your tank

As its already been said I doubt I killed much bacteria. The plants that have algae will likely be replaced with live plants, and the gravel, walls of the aquarium, filter cartridges, and one of the logs was in the tank before "the cleanup" and I'm sure they all have enough bacteria on them. The 30-60 filter also has the two sponges for bacteria as well so I'm not worried about a loss of bacteria.

I do also have a pump pushing air through a length-wide airhose in the back; I learned a long time ago about breaking the surface to add oxygen to the tank.

t looks like you lost all of your bacteria..
It would have been nice for someone to say somthing about not cleaning everything all at once! ouch.. I blame this on me.. I thought you were getting good responces so I failed to respond myself.. sorry about that
You might want to invest in some BioSperia or your going to be going through a new cycle..

Again, I doubt I lost any bacteria.

As long as the tap water wasn't scalding hot, it probably didn't kill much bacteria on the filter media.
And the walls of the tank are coated with bacteria too.

I don't feel the whisper 30-60 is enough flow for a 55gallon. I'd look into replacing it with the biggest AquaClear hang on they make (Used to be called AC 500, I think it might be the AC 50 now), or the next size down, an AC 30, and run it with the whisper.

No, the water I replaced the old water with was cool (probably 78-82 degrees).
I'm planning on buying an Emperor (400 I think?) in the next few weeks. I'll be getting one that is adequate enough for a 60 gallon (if not the next one up). I'm sure there is no such thing as "too much filtration power."

You have an ammonia test that goes to 10? That is super high. What sort of dechlorinator are you using and do you have chlorine or chloramine in your water. It is easy to find out if you have chloramine if you call your water department.

In the future clean the filter using old tank water that you remove. It is safer for the bacteria as the chlorine will kill some off. I doubt vacuuming each week will kill any bacteria and IMO should be done.

I don't remember the # value on the ammonia test, but it was the second from the lowest...I know lowest is 0, I thought maybe the one above that was 10. I'm sure I'm wrong and it's like .25 or .5 or something...can anyone with a test kit handy verify this (if not I'll do it when I get home from work).
Thanks for the idea on using old water to clean the filter - I will do that in the future.

etest of the ammonia and nitrite would be needed to make sure your bacteria is ok.. they both should be 0.

I will retest when I get home and post it here.

Thanks again everyone, you are all the reason why I love this site.

 

[zero2dash]

I retested the water.
(All of these match my readings from last night; I think I was off 1 color on the Nitrates but it's still low now.)

pH 6.4
Ammonia 1.0ppm
Nitrite 0ppm
Nitrate 20ppm

2 more of my bloated pink gourami are dying. Came home and they're breathing but motionless and really "floaty". I put them into a little baby net/cage thing in the tank 'cause the other fish started trying to eat them.

 

[aqh88]

I did say change the water daily for awhile and do not do a gravel vac each time.... Chances are with that many fish in that tank you did remove enough bacteria to end up in at least a small cycle. I would test the ammonia daily or at least every other day for the next week and do water changes as needed. I'd be very surprised not to see a fairly high ammonia spike on that tank. I'd try to keep it below 1ppm or you could lose more fish.


edit: oops too late again...

 

[greenmaji]

Well.. doing a water change to get rid of some of that NH3 should help 50% will drop it to around .5ppm but im not so sure 1ppm should be killing your fish.. I dont know how sensitive they are..and your ph is well under 7 so alot of the ammonia should be in the non toxic NH4 form..
How sensitve are those fish? I dont have any expeiance with them..

 

[zero2dash]

Before doing all of this last night, my water was:
pH 6.4 (I believe)
Ammonia 0ppm
Nitrite 0ppm
Nitrate 160ppm

So I didn't have any ammonia or nitrite before...obviously because it was old water I'm assuming...?

As for the fish, I believe they're called bloated pink kissing gourami; I did a google search and found nothing. Serves me right for buying them from Petsmart...I guess they've got a mad scientist and a lab coming up with weird breeds or something. Anyhow being that they're a gourami I figured they'd be hardy like all gourami are but maybe I'm mistaken about these ones?

Anyhow I'll keep an eye on it daily as I should and post what happens as it occurs.
1) Should I continue with another water change tomorrow night...25%/50%...?
2) Should I hold off on buying the Emperor 400 til, say, this coming weekend? (Or does it matter? The reason I ask is because of the bacteria in the old filter, and obviously if I buy a new filter it will have 0 bacteria.)

Thanks again for everyone's help and insight.