Nitrates won't come down no matter what we do!!

[Jasonandmolly]

Hi all!
Done lots of reading and research, understand everything about maintaining the scrubber (as far as we know) but still have nitrates at 50ppm or higher, every day.

Here is the info I can think of to share:
90 gallon reef & fish display with 30 gallon sump (so about 100 net gallons)
Tank is about 3-4 years old
Scrubber been going for 2.5-3 months
Black algae at first, so we increased flow and lights (now up to 6 23w CF lights)
Now mostly brown slime and some green hair algae
Screen is 10x12 approximately.
Black algae, when it appears, is cleaned immediately. Hair and brown algae cleaned every 2-3 days, one side at a time.
Inside of sump is covered with red and hair algae.
We feed about 1 cube of frozen food/day

Scrubber did get rid of all the algae in our display tank really quickly, which is great because it was overrun with hair algae. yay!
But the nitrates WON'T come down.

Anything we can do/might be doing wrong? Getting some SPS soon and though current tank seems uneffected by nitrates, the SPS won't be so happy. What could be causing this?

Thanks for your help!!

[SantaMonica]

Start by letting it grow more days... up to 14.

Pics of the screen before cleaning would help.

[Jasonandmolly]

Also, I have two Sera Nitrate test kits and each will give me a different result, and if I mix up the components I'll get a different result, and if I use the same combination of reagents, I'll get a different result each time. In about 7 or 8 tests I got 0, 10 at least twice, 25 twice, 50 twice and 100 once... ?!?!?!

[SantaMonica]

Well then the real test is how the display looks. I don't really test mine anymore... I can tell by looking at it.

The main thing is if there is algae on rocks, and plastic.

[Floyd R Turbo]

Personally, I use the API Nitrate test kit for anything over about 10ppm, I find it is highly accurate once you figure out how to read the results, and it is extremely important to shake the #2 bottle for at least 30 seconds to dissolve the sediment in the bottle. Follow directions to the letter and you get good results. Hold the vial against the card in good light and then stand it on the card to get a couple different perspectives, and once you get used to how to read the results right it's very accurate.

For under 10ppm I use Salifert. Again follow directions to the letter.

Never used Sera but never mix reagents from 2 different test kits. Sometimes each batch has slight variances but the different components are verified to work together for that batch. Also your kits might be out of date. When in doubt, get new ones. I would say bring to LFS but whenever I've done that, they never run the test right so it's a dead end. Better to find someone with a good test kit they are familiar with and have them test it.

[Jasonandmolly]

Thanks for the tips! If my nitrates are, in fact, high - what should I do besides maybe not cleaning the screen as often? See if my new SPS corals die? LOL

[Floyd R Turbo]

You only need to clean the screen before 7 days if you are getting very dark brown to black growth. If you are getting brown and maybe a little hair, you need to let this grow out as filtering capacity goes exponential the later you leave it. So go 7 days minimum, 10-14 if you don't get detachment.

[Jasonandmolly]

Thanks again! We'll try leaving it longer between cleanings and we'll get another test kit today and see how that goes.

[Jasonandmolly]

OK we got the API kit and not sure if we should read it as the tube pushed against the card (reads at 40+) or a tiny bit in front of the card (20ish). Depends on how much light goes through the color. ???

[kerry]

I hold mine at arms length under a bright light over a white paper laid on the counter. This method of reading I have found seems to be accurate. I guess you would not want a shadow cast on it. Then I hear about people setting in on the counter standing up and looking through the top with the cap removed?

[Floyd R Turbo]

No, do not look down through the vial with the cap removed. This will give you a reading much higher than what it actually is.

I wrote this up on another forum a while back. It describes my method for reading the API Nitrate test.

http://www.aquariumadvice.com/forums/f60/observations-on-api-test-kits-126327.html

Granted this was written for FW I think, and the SW color card is a little different. 40ppm SW is closer to 20ppm FW.

Here's the way to 'calibrate' yourself to understand what the reading is. Take a sample of your tank water and run the test. Then take another sample and dilute it 50/50 with saltwater with 0ppm Nitrate (mix up a small amount of fresh SW using RO/DI or distilled water and test it to verify Nitrate = 0). Test this and it should be half the reading. 5ppm and 10ppm look about the same. So what you're going for here is getting a sample diluted down to a 10ppm reading, then multiplying it to get your actual result.

So let's say you had to dilute 3 parts fresh SW to 1 part tank water to get a 10ppm reading. In this case, you have 25% tank water, so you multiply your result by 4 and your Nitrate is at 40 (roughly). But you get the idea.

I have used this method to determine levels of nitrate far beyond any test kit. I have 2 tanks in restaurants (without scrubbers - yet) and they don't have extra $ for maintenance in these economic times, so the Nitrates are at 500 and 800. Fish are fine and will be, but I can't add anything to the tanks. Plus they will be the lucky recipients of a test scrubber.

But I find that orange readings are generally just a slightly darker shade of orange when held against the card versus hovering slightly above it or standing on top of the card and looking at a 45 degree angle, and this corresponds to about 20ppm. If you get a orange with a slightly red tint when standing/hovering that turns a more pronounced shade of reddish orange, but not quite red, corresponds to 40 ppm. Anything over that will look starkly red without any orange tint, an honestly anything over 40ppm (80 to 160ppm) is next to impossible to differentiate.

[Ace25]

I read my tests by placing the vial/container directly against a white background. Phosphates I only trust a meter, no liquid test kit can give us the accuracy we want for the hobby. API is good for Nitrates, Alkalinity, and Calcium (and I am sure ammonia and nitrites but I never use those) but anything else I would go with Salifert.. actually, for myself I only use Salifert because I find them easy to do and about the easiest to accurately read.

http://farm7.staticflickr.com/6111/6295415900_b1b094c22d.jpg

[Floyd R Turbo]

I didn't like the API Alk or Cal test kits. Too inaccurate for my liking. I swear by Salifert for these 2, and low Nitrate also. Magnesium is also very good but tricky to see the color change sometimes. Hanna Checker at a minimum for Phosphate (they have Phosphorus too which measures in ppb and you convert to ppm Phosphate and is much more accurate I guess) and I hear their Alk meter is good too, but not the Cal meter - PITA. I use a Hanna combo pH/Conductivity meter that I love also. NIS refractometer (eBay).

Ace your Nitrate test looks exactly like mine - slightly yellow = 0.00 yay!

[Jasonandmolly]

So yesterday the test kit said about 40, the only thing we did since then was a 10 gallon water change (with 0 nitrate water) and turn on the protein skimmer again (just to see what happens) and this morning the nitrates are 80. ???

[Floyd R Turbo]

I would think either your test kit is expired or you are doing the test wrong. If the test was done wrong, I'd say it was the one that resulted in the 40ppm reading. If you don't shake the living hell out of the #2 bottle, you will get a low reading.

[kerry]

Also note you might not get correct readings if you have done tests without shaking the #2 bottle well. I would suspect this would change the ratio of the different things in the bottle you have to mix up???? Maybe, just a thought.

[Floyd R Turbo]

That's true, the concentration of the reagent would be off. This depends on how many tests you did before doing it right I suppose.

[Fish Friend]

This info. is very very useful. I could have written these questions myself! I am having exactly the same problem with high nitrates & reading the API test results. So I will also leave the algae to grow for longer as well. It is very interesting to hear of your very high nitrates in your restaurant tanks. All the other parameters are ok in my tank so does that mean I shouldn't worry too much about the high nitates until the scrubber really starts working well?

[redadeath]

try to decrease biload first
remove some fish
increase flow
stop feeding for 4 or 5 days
reaquascape

or

make bigger scrubber

[Fish Friend]

Unfortunately the scrubber size is limited by my sump size but my fish are getting a bit on the chunky size! So I will cut down the feeding (from 3 cubes twice per day) and increase the flow. I will keep you posted.
Many thanks.

[Jasonandmolly]

OK so we've left the algae to grow for a few days - it's not getting very thick (in terms of distance from the screen) but looks lighter green, so that's good. Especially right in front of the whiter lights. Our nitrates are still 80, though. Jason is worried that the SPS corals that we just put in last week are going to die. Some are pale and not opening... Although I know they were not in the greatest of health when we got them.
WHY can't we get the stupid thing to work???

[SantaMonica]

Need pics of the screen before and after cleaning.

[Jasonandmolly]

Here are pictures of the scrubber and the tank things that seem to not be doing well. You can see there is no algae in the tank, which is great. But the zoo polyps are all closed up and the new SPS corals don't look good. Sorry the fish like the camera. :)
For the scrubber I'm showing you a farther away shot so you can see the whole setup (lots of lights - seemed like that might have been the problem originally but hasn't helped - and we've seen other scrubbers with practically no light by comparison, that work well for them). And then a pic of the other side too.
1529153015311532

[Jasonandmolly]

Will clean and take more pics if you think it needs cleaning.

[Jasonandmolly]

1533
Here's a closer pic of the left side too. See how it's lighter green right in front of the light. Not black anymore anywhere, but still kind of flat and slimy in most parts, with some hair and texture. And of course that the nitrates aren't going down.
FYI this is a screen made from the plastic tank divider instead of the craft plastic canvas. Would that matter this much? It is rough. Just not quite as 'holey'.

[Jasonandmolly]

1533
Here's a closer pic of the left side too. See how it's lighter green right in front of the light. Not black anymore anywhere, but still kind of flat and slimy in most parts, with some hair and texture. And of course that the nitrates aren't going down.
FYI this is a screen made from the plastic tank divider instead of the craft plastic canvas. Would that matter this much? It is rough. Just not quite as 'holey'.

[Jasonandmolly]

Oops I posted that last one twice somehow. Here's a bigger version of the fishtank pic so you can see the detail better.
1534

[kerry]

The canvas works well, I tried the divider(because I had is laying around) which was just ok. I had much better results with the canvas for sure.

[Jasonandmolly]

Well if I change that now, I'll be starting over from scratch with the scrubber. Is it worth it, considering the nitrates aren't lowering anyway?
On another note, how in the world can we have no algae in the tank when we have 80+ nitrates?

[kerry]

You have a nice tank Sir.
Not sure why its so high Sir. Mine didn't come down a whole lot until I got my canvas so that might have something to do with it.
The algae in the tank will happen if the nitrates stay up.
You do not have to start over from scratch, you can seed your new screen.
You can get a canvas screen, rough it up real good, and then rub your old algae screen all over both sides of the new one. Then give it a light rinse to get the loose material off and connect it to your set-up.

[Ace25]

I have always found nitrates the easiest "problem" to fix. Since there is really no ill effect with lowering nitrates quickly a nitrate problem can be fixed in under a week if you have the time and $ to do it. I have fixed tanks with nitrates over 200 in under 5 days, getting them down to under 10. The way I do this is LARGE water changes.. talking 95%. I did this on a 100G tank and it took 400G of water ($100 worth of salt, 2x 200G boxes of Reef Crystals) to fix it. It went from a tank neglected for over a year to almost pristine looking in 5 days time by doing almost complete water changes daily. First day, nitrates start at 200, do a large water change, nitrates are down to 100 immediately after water change but 24 hours later it is back up to 160 due to nitrates leaching from the sand and rocks. Just keep repeating the water changes until the nitrates finally stay down, at which point you will know they have pretty much all leached out of the rocks and sand. After the 4th 100G water change on the tank, 24 hours later, nitrates finally stayed under 10 and now that the owner keeps up on maintaining the tank it has never risen above 20.

[SantaMonica]

Problem is obvious... lighting not in front of the screen, and wrong screen material, is only giving you 1/4 of the filtering.

Throw that material away, and find a way to get the lights one light reflector directly in front of each side of the screen. You'll probably need to get side-reflectors.

[Jasonandmolly]

OK, we'll try replacing the screen material. We already have the canvas - we bought it a few weeks ago in case we decided to try that. For the lights, I see what you mean - but considering there are still 6 lights on the thing it shouldn't be not working at all.

[kerry]

I had doubts until I got my screen and lights right, now its zero nutrients across the board!!!!!

[Jasonandmolly]

@Ace25 - thanks for explaining... we've tried water changes with no change in nitrates at all, but not huge changes over and over like that. We'd wondered if nitrates were leaching from rocks and sand to the point that we can't get them to go down below 40-80. My husband wants to take all the stuff out of the tank and trash it and start over, he's so annoyed. It's been like two years we've struggled with either hair algae or nitrates and thankfully the algae is gone. But he feels like he's just not good at keeping a tank, for whatever reason, even though he tries hard, researches, and isn't any less smart than anyone else who would set up a tank! LOL It'd be hard to get up the water supply in our house for that big of a water change, but we'll keep that idea in mind.

To everyone: Is it likely that our nitrates will spike for awhile now that we're putting a new (seeded) screen in and took off the old screen?

Thanks!
Molly

[Floyd R Turbo]

They might. But it depends on many factors. If you have a lot of LR (2+ lb/gal) and it's well established (and porous) it will do a pretty good job of keeping N down for a couple of days, and the slime that grows on a new screen is actually quite efficient at N export.