High Nitrate Levels

[jfenton954]

My 75g tank has had high nitrate levels for a while now..... :(. Some of my acans are slowly dying I think because of it. The levels are between 60-80 ppm. I did a 40% water change a couple of months ago but that didn't seem to work..I also cut back feeding to try to help. I have a 10x10 screen with 4x 23w cfls that I change every 3 months. The screen seems to be thriving the best I've ever seen it. My bio load is 90lbs of live sand, 175lbs of live rock, 20lbs of crushed coral in sump and 14 fish. I run the lights on the screen 18 straight hours now, would running the lights 24/7 help get rid if the nitrates faster? (I would have put pics up but can't log into site through tap talk.)

[Floyd R Turbo]

A thriving screen can be sort of relative. I picture will tell the story. Try to find a way to post a few.

A few questions.

10x10 screen is 100 sq in / 12 per cube = about 8 cube/day screen. Is that how much you are feeding? Is the screen sized per feeding, or per the old water volume based guideline?

What is your Phosphate at? What do you use to test that?

Have you ever tested potassium?

Are your other general parameters in line? Alkalinity, Calcium, Magnesium?

Lights at 18 hours are really your max for CFLs. 24/7 will not really help, but you might be able to push it to 20 hours/day. Algae needs a dark period.

The first thing I would try is increasing the flow to the screen and the intensity of the light. So this would mean a bigger pump and higher wattage CFLs.

Or, you could decrease the screen size, which would increase the flow per inch of screen width, and then switch lights to higher wattage but less of them. Increasing intensity and flow will get more green algae growing, which filters best.

But...pictures are really needed to make a good recommendation.

[jfenton954]

A thriving screen can be sort of relative. I picture will tell the story. Try to find a way to post a few.

A few questions.

10x10 screen is 100 sq in / 12 per cube = about 8 cube/day screen. Is that how much you are feeding? Is the screen sized per feeding, or per the old water volume based guideline? Was feeding 8cubes a day went to 4

What is your Phosphate at? What do you use to test that? Haven't tested that

Have you ever tested potassium? No

Are your other general parameters in line? Alkalinity, Calcium, Magnesium? Didn't think that would be the problem.

Lights at 18 hours are really your max for CFLs. 24/7 will not really help, but you might be able to push it to 20 hours/day. Algae needs a dark period.

The first thing I would try is increasing the flow to the screen and the intensity of the light. So this would mean a bigger pump and higher wattage CFLs.

Or, you could decrease the screen size, which would increase the flow per inch of screen width, and then switch lights to higher wattage but less of them. Increasing intensity and flow will get more green algae growing, which filters best.

But...pictures are really needed to make a good recommendation.

[SantaMonica]

Yes the growth is good for its size, so it just a matter of needing a stronger/larger scrubber, or waiting for P to come out of the rocks.

[Floyd R Turbo]

I always ask the question on general parameters, Alk/Cal/Mag because those are the basic ones that those need to be right, and if one of them is constantly fluctuating this can cause unhappiness.

If P is zero, and N is high, then you're limited. So it might help to know where P is at. very high P can also cause problems. If N and P are both there and other fixes don't help, then you might test for K and see if that is low.

So, now to your pics.

Your growth looks pretty good! Large chunks and thick growth. Flow looks good from what I can tell, but do you know what it is (GPH)? Overflow fed or pump fed?

your lights appear to be pointed at a downward angle. They should be pointed perpendicular to the screen (horizontal). This will inscrease intensity. Looks like a cramped area though. Also you can remove the dome/cone reflectors, the CFL floodlights have them built in.

How often do you clean the screen?

[jfenton954]

My tank has been established for about 4 years now.

[Floyd R Turbo]

My tank has been established for about 4 years now.

If you have been on a ramp-up of nutrients, evident by the high N, this might be driving phosphate into the rocks. That means once you fix the issue and lower P in the water column via scrubbing, you might start to leech them back out. This is what SM was getting at.

[Garf]

Looking at your previous posts from 3 years ago,you've always had certain concerns with the effectiveness of the scrubber (lighting, pH levels,flow etc). Did you ever get it to work properly in reducing nitrates ?

[jfenton954]

oh sorry.... I didn't know that, I wasn't trying to rude. So stronger lights will do the trick??

[jfenton954]

Yes I did I was running perfect at 0 ppm for a long time then I bought some led grow lights that screwed in like the cfls and work got busy so my girlfriend didn't realize that little to no growth was bad so I've been trying to get the nitrates to go down now for a while now :(. Which makes sense now that MS said about the P in the rocks :)

[Garf]

What's your pH and phos levels, out of curiosity?

[Floyd R Turbo]

Ah, ok. So it was working well at one point (which makes sense, considering the growth). The LEDs might not have been the proper spectrum, proper strength, or positioned wrong, too many possibilities to go into there.

So how long has it been since you switched back to CFLs and started getting good growth again?

[jfenton954]

Its been at least 2 months with great growth thats what worries me. I also am worried because I have 3 watannabe angels and one is changing into a male.

[jfenton954]

There's also no algae growth in the tank other than coraline.

[Floyd R Turbo]

Hmmm...ok, might be a dumb question but how new/reliable are your test kits? (worth asking...you never know)

If you are getting good growth for 2 months, and the last PWC you did was also a couple months ago, and 40%, I would consider another 40% PWC, followed by one more a few days later to try and 'reset' the system back closer to the lowered levels.

If you were feeding 8 cubes/day and it was handling it well, then it was balanced. When it got out of whack, it can only handle the 8 cubes/day but not the excess built-up N. Get it back down with PWCs and feed 4 cubes/day until you see the N dropping on it's own.

Sounds like you may have had a nicely balanced system, should be able to get that back.

[jfenton954]

My ph 8.1 phos. 0.25ppm

[jfenton954]

My test kit is a year to year 1/2 old

[Floyd R Turbo]

Test kit could be expired. Might be giving you a bad result. But, it's probably not that far off.

I would do another PWC, test N and P a few hours later (call this "day zero" - more below), then let the scrubber grow for a week. Try to get the lights pointed more directly at the screen.

When you clean the screen, don't remove it all. Try to leave enough on there to get continued filtration. Clean enough off so that you are not getting shading, but not so much that you end up with a 'gap' in the filtration period, which would allow the nutrients to start ramping up again. you might consider cleaning one side at a time, every 3 to 4 days. You want the growth to continue, but not get so thick that the screen starts to die at the lower layers and feed nutrients back into the water.

Test the water at 3 days after the PWC, and then again at 7 days. More often if you like. If you don't see a drop from day 0 to 3, and again from 3 to 6, do another PWC on day 6.

[jfenton954]

I will try all of that then give you an update. Also I've been trying a different way to clean the screen to get the turf algae to grow better it seems to be working. Instead of scrubbing one side clean I take the sink sprayer at full blast and spray both sides off the thick turf algae gets thicker and seems to grow better, I do check the bottom of the thick patches and it seems to do fine and grows pretty fast.

[jfenton954]

I did a 36g water change, by volume that was about 60%. I got the nitrates down to 10-20 ppm I think that's a lot more manageable than it was. But will continue your step through until til water is at 0 ppm like before thank you for your help.

[Ace25]

I will try all of that then give you an update. Also I've been trying a different way to clean the screen to get the turf algae to grow better it seems to be working. Instead of scrubbing one side clean I take the sink sprayer at full blast and spray both sides off the thick turf algae gets thicker and seems to grow better, I do check the bottom of the thick patches and it seems to do fine and grows pretty fast.

I have noticed this as well on one of my systems.. the screen grows very well, but also catches a TON of detritus. So much than when I wait a week and take the screen out to clean the first minute of running water over it like mud coming off the screen. I know this isn't an answer that people want to hear, but I have found rinsing (not cleaning the algae off) the screen every 1-2 days really helps with the growth.

I also had some issues with the 'screw in' LED bulbs I bought, but I found out (using a real spectrometer at work) that the spectrum is not even close to ideal for photosynthesis (620-630nm reds, but were listed as 660nm). $70 worth of screw in LED bulbs wasted, $20 of DIY parts to make my own with known good LEDs fixed the growth issues. It should be a crime to market bulbs as something they are not, ie, 'Grow Bulbs', if they don't contain the proper spectrum for photosynthesis. Unfortunately it seems a large majority of the sellers are doing just that, passing off junk to customers.

[Floyd R Turbo]

Ace, good to know. Thank you for sharing.

[tebo]

ace greetings, you do rinsing with fresh water or aquarium itself,,, after 7 to 14 days if the algae clean normal??

I stop using the vsv,,, so incredibly dirty wore glasses, but IMMEDIATELY my nitrates went from 1ppm to 10ppm over

I think it's a concentration of detritus in the sump,

[jfenton954]

So could detritus build up in my crushed coral in my sump cause nitrate levels to rise and stay in tank?

[SantaMonica]

Detritus in your tank or sump feeds the animals if you have them.

[Floyd R Turbo]

yeah I think the "built up detritus causes nitrates" is mostly people talking out of their rear ends. Unless you have a LOT of it, and I mean like 1/4" layer over the whole sump, then maybe it might be contributing. But when your scrubber is operating as it should, food in = nitrate in => scrubber => nitrate out and there is no room for it to "build up" and then "leech out" or "become a factory".

I have not seen any evidence that detritus in itself causes a "nitrate factory". I think poor tank maintenance creates a nitrate factory. Dunno, maybe I am wrong.

People create entire benthic zones in stand-alone tanks for the purpose of letting the detritus settle out and feed a microcosm, so I fail to see how detritus buildup is an issue, again, in and of itself. With the absence of the microcosm, maybe. But not to the point that you are having (but a pic might change my mind).

[jfenton954]

Here is a pic of my sump with crushed coral an LR the bed is about 3 inches deep.

[Rattzreef]

Detritus in your tank or sump feeds the animals if you have them.
Detritus feeds bacteria not animals.. what animals does he have in the sump that feed on fish poo? the amount of worms and critters needed to consume waste(detritus) at the level we have in our tanks is unreachable and impractical, leaving it available for bacteria to break down.. Even pods by the thousands couldn't deal with all of it.. I'm sure if corals had the choice they would eat something other than detritus and fish waste.. And fish prefer foods not poop last time I checked.. lol just found this comment rather odd and misleading..