Nitrate Misery

[johnnyjtaylor]

Nitrate my arch nemesis, each week by water change day it gets up to 20ppm and I don't know why!!!!
My set up is 125l with 20kgs live rock,mce600 skimmer,2 seio m620 power heads,96w of t5(2x14,000k marine whites 2xactinics).
Its stocked with a pair of percular clownfish,a pair of bangaii cardinals,a pair of firefish,2 skunk shrimps,a peppermint shrimp, hermits,snails and various corals.

Each week I've been doing a 25l water change to try to get the nitrate down but it doesn't do the trick also I have 0.25ppm phosphate at the end of each week despite rowaphos(regulary changed) being in the skimmer.All other paramaters are good(calcium 400ppm,ph 8.3,1.025 specific gravity with refractometer)

Questions.
1. Am I overfeeding?I feed two blocks of frozen food every 3 days(that is a third of a block a meal fed twice a day) with the occasional meal replaced with flake or cyclops.
2. Skimmer. I get only half a cup per week out of it(the cup being much narrower at the bottom so really not a great deal of skimmate) I got the skimmer second hand and it didn't have a venturi valve on the air pipe so I put an air tap in it and adjusted it the best I could to get as much foam depth as I could but I cant help but think maybe its not a fine enough adjustment as it needs(never seen anyone elses in action to compare it to). Should I be getting more?
3.My torch coral is suffering and is showing skeleton through the heads(not good) and my brain isn't looking too happy either, I'm guessing that this is due to the nitrate and phosphate build up but I'm slightly suspect of the frogspawn which has grown rather large from 1 head to five in 9 months.Any ideas on this?

Thanks in advance Johnny

 

[steelhealr]

Feeding to excess can increase phosphates. Two blocks sounds like a lot ot me every 3 days. What kind of water are you using? SH

 

[SkiFletch]

Hummm, is the frogspawn touching the torch?

 

[johnnyjtaylor]

Thanks for replies

SH. How much food would you think was about right given my stocking level?(the frozen blocks are 3/4" square by 1/2" deep). I mix my own sw from aqua medic reef salt and water from my ro unit(zeros all the way from it)

Ski. I leave a good gap between the frogspawn and everything else but the torch is directly down flow. Would the frogspawn have to physically touch another coral to do any harm? I ask this because my toadstool seemed to hate being near the frogspawn(although I was never sure whether it was that or the fact that it was the highest thing on the rockwork and the skunk cleaners used to cling to it).

Just to make sense of what I mean about my amount of skimmate,I'm only getting about 50~60ml a week.

Cheers johnny

 

[sophos9]

Does your RO unit have a DI chamber, I'm yet to see an RO that outputs 0...?

I'm stocked with a Starry Blenny, 2 Clowns, Peacock Wrasse, Dragon Wrasse, Orchid Dottyback, Mandarin and 4 shrimps. They get fed twice a day, once is with flake other is with half a cube of frozen - I consider this over feeding!!

I dry skim and currently pull about 1.5cups out a week...

 

[jeasko]

what test kit are you using for nitrates?

there seems to be a real issue with measuring nitrates as there are different was of doing it, the api kit i used showed anywere between 10ppm - 160ppm when infact it wass closer to 15-20ppm as varified by LFS and a fellow marine keeper one using salifert test and the other JBL

 

[dilbert]

I consider this over feeding!!

No, no, me, me, here, here, I am overfeeding!


For two little fish of the size of an inch I add in the morning a few marine flakes and in the afternoon and in the evning they a cube of frozen food of the size of a key on a standard PC keyboard. Every day because juvenile fish.

Before that, they got an additional cube or two AND live food from Friday to Sunday so that knocked the system from its balance and I got a cyanobacteria outbreak.


I only installed a third powerhead for horizontal and a fourth one for vertical flow (yes, there is still some space left for the fish ) and I was astonished that only with this measure the cyanobacteria began to vanish from the sand and some live rock. (Maybe the water conditions were too bad for them. )

Now, when I scratched all the resting cyanobacteria at once (maybe not so good) from the glass I got yesterday after a 20% water change (RO water) a reading of Ammonia 0, Nitrite 0.25 ppm, and Nitrate 40 ppm. With Dry-tab tests, the super API tests still show 0, but showed something in the past on other occasions, so they principally work, maybe somewhat less sensitive?

All in all, only the zoas (well no need to look at hardy fish or shrimps) kept mostly close at the beginning at the cyanobacteria outbreak. I measured phoshates, too, and they were 0.25 ppm as always.


My guess is that there is another condition that I have not tested for and maybe there is not test for, that made the zoas shut. Because when nitrates have risen slightly from 20 to 40 ppm, the zoas opened again.

The nitrite and nitrate reading stem simply from putting to much load on the nitrofying bacteria and that can have many causes apart from overfeeding like rotting accumulated detritus anywhere hidden or simply scratching too much cyanobacteria off the glass.

Well, not really an answer, only a similar sceanario, but maybe it's helpful.

 

[Colin_T]

20% water changes won't do much to dilute nitrates or phosphates. Afterall you are only diluting the nitrates by 1/5. Then over the course of a week they only have to go back up 4 or 5 ppm to get back up to where they were before. A bigger water change would make more difference.

Torch corals and brain corals should be able to tolerate 20ppm nitrates. I would be inclined to think the frogspawn coral is sending out sweeper tentacles during the night and attacking everything around it. The sweeper tentacles can reach up to 8 inches or more. Anything within its range is fare game for a good stinging.

2-3 blocks of frozen food every few days isn't much really.

You could try growing caulerpa in the tank to help reduce nitrates.

 

[sophos9]

Tests by Randy Holmes-Farley shows us that a 100ppm nitrate tank would be reduced to approx 3ppm by a 30% water change, a 7.5% would reduce it to just over 40ppm

Tank nitrates increase by approx 0.1ppm per day, a 30% monthly change gives us nitrate concentration reduction to just 9ppm per year whilst a 7.5% allows 64ppm per year!

A cumulative period of a year (with concentration in between the changes) shows us that a 30% would keep the tank at 5ppm where as a 7.5% would be around 70ppm (remember starting at 100ppm tho)

 

[dilbert]

Tests by Randy Holmes-Farley shows us that a 100ppm nitrate tank would be reduced to approx 3ppm by a 30% water change, a 7.5% would reduce it to just over 40ppm

I had a short Web search but couldn't find any examples of this strange nitrate maths.

I always had the impression that a 50% water change reduces 100 ppm nitrate to 50 ppm. Also, I had the idea measurements before and after a waterchange (did that only a few times in my brackish tank) would confirm that popular belief.


And @ Colin_T

I don'y bother much of this nitrate concentration (as everybody in the tank seems to be happy apart from the cyanobacteria ) and will rather observe how long does it take for those nitrying lethargics to bring that figure down.

I also got Chaetomorpha in my tank, brought with my first live rock. I only recognised it when I was up to buy it. It's only a small ball that grew from a single string that I thought to be a "hair algae" and I'll buy probably more when I got a good idea where to fix all this stuff at best (no space for a refugium).

Caulerpa I got also in my tank. It came piggyback with the live rock the zoas are on.

The problem with feeding is that I spread already the cube into up to ten different servings over a period of 2 or 3 hours, but overall the Nemo is eating until the end but both Nemo and damsel discard about 90% and I know from the fact that I feed the rest of the cubes go to the platys that this stuff must be unattractive junk food, at least the most part of it. But also live food gets only consumed to 30% max. Netting out the rest is easy said in a nano reef.

 

[sophos9]

Dilbert, strange hey... <edit: I neglected to mention this is over a year>

Heres the article (well worth a read), post back with your comments...

 

[dilbert]

Well, now it's clear.

I can stay with my popular beliefs.


Nothing beats common sense ...

But thanks for the link to the article. Will read more in the evening. (Have to leave my desk, now. )

 

[SkiFletch]

Johnny, the frogspawn's tentacles would in fact have to touch the torch to do it harm. As mentioned, sweeper tentacles can be extended from these LPS within the first couple hours after lights-out. Usually after that though, they close up and sleep for the night

 

[johnnyjtaylor]

Thanks Ski, I've never seen any sweeper tentacles come out of it ,it always closes immediatly when lghts off.
I'm moving house in a couple of weeks or so and transfering everything to a 180l tank so I'm hoping a bit more room and a bit more water will help keep levels more diluted.
cheers Johnny