Cyano/high nitrate/water changes

[Auquanut]

I've had my 125 gallon mixed reef running for about 8 months now. Within the last few months I've been adding some SPS corals. (stylophora, pocillopora, birdsnest) All SPS, LPS and softies seem to be doing fine. I have a 30 gallon wet/dry filter (I know, I know). I'm using poly fill quilt backing on egg crate on top of the bioballs for mechanical filtration, a protein skimmer rated for 240 gallons and an external return pump rated at 1320 gph (awesome flow). I also have a total of 5 power heads on 2 wave makers, so turbulence and surface agitation seem to be great. Oh, one more thing. I'm using a BRS dual GFO/carbon reactor.
Here's the thing, my nitrates seem to hang around 20 ppm. I try to do about a 30 gallon water change about every week to 10 days and even after the water change the nitrates don't change much if at all. The interesting part is that I have a minor issue with cyano in one portion of the substrate. After a water change, it seems to get much worse. The longer I wait between changes, the better it seems to get. Not sure what I should do. Seems like smaller or fewer water changes will mean higher nitrates, but the tank and corals seem to like reduced water changes. I've got water brewed up and ready to do a water change now, but I'm thinking maybe I should wait awhile and see how the tank responds. How long can I keep the new water before I have to use it or lose it?
Any thoughts?

 

[Crabs McJones]

I've had my 125 gallon mixed reef running for about 8 months now. Within the last few months I've been adding some SPS corals. (stylophora, pocillopora, birdsnest) All SPS, LPS and softies seem to be doing fine. I have a 30 gallon wet/dry filter (I know, I know). I'm using poly fill quilt backing on egg crate on top of the bioballs for mechanical filtration, a protein skimmer rated for 240 gallons and an external return pump rated at 1320 gph (awesome flow). I also have a total of 5 power heads on 2 wave makers, so turbulence and surface agitation seem to be great. Oh, one more thing. I'm using a BRS dual GFO/carbon reactor.
Here's the thing, my nitrates seem to hang around 20 ppm. I try to do about a 30 gallon water change about every week to 10 days and even after the water change the nitrates don't change much if at all. The interesting part is that I have a minor issue with cyano in one portion of the substrate. After a water change, it seems to get much worse. The longer I wait between changes, the better it seems to get. Not sure what I should do. Seems like smaller or fewer water changes will mean higher nitrates, but the tank and corals seem to like reduced water changes. I've got water brewed up and ready to do a water change now, but I'm thinking maybe I should wait awhile and see how the tank responds. How long can I keep the new water before I have to use it or lose it?
Any thoughts?

What is your source water? Are you using ro/di and is it 0 tds? How heavy are you feeding and how many fish do you have?

 

[Auquanut]

I have a 75 gpd ro/di unit. TDS just went from 1 to 2 ppm. Gonna have to change it soon.
Livestock:
Hippo tang
yellow tang
Kole tang
Foxface rabbitfish
Melanaurus wrasse
Atypical ocellaris clown
Platinum perculla clown
2 Engineer gobies
Pink rose urchin
Red tile starfish
Maxima clam
2 Skunk shrimp
Minimal CUC
I feed once a day. I turn off all pumps during feeding, and they seem to do a good job of getting everything. I feed a portion of a cube of mysis and omnivore cube nightly (probably about half a cube total), a few flakes and sinking pellets. They also get nori on a clip every other day.
Forgot to mention that my lighting is an AquaticLife unit with 3 metal halides, 4 T5 actectics and 6 blue LEDs. Got it for a song.

 

[ndrwater]

Pretty high bio load with all those tangs. Kinda explains the nitrates, which at 20 isn't really all that bad. Probably explains the cyano a bit too.
I agree with Crabs above, sounds like a source water issue if you are seeing a fluctuation in cyano after a water change.
What kits are you using to test? And have you tested your new water before adding to the tank?

 

[Crabs McJones]

Pretty high bio load with all those tangs. Kinda explains the nitrates, which at 20 isn't really all that bad. Probably explains the cyano a bit too.
I agree with Crabs above, sounds like a source water issue if you are seeing a fluctuation in cyano after a water change.
What kits are you using to test? And ha e you tested your new water before adding to the tank?

+1 for the bioload as well.

 

[Auquanut]

Using API Master Reef Kit. Never thought of testing the new water before water changes. I use Instant Ocean Reef Crystals. Do you think that makes a difference? I intend to replace the wet/dry filter with a sump with a fuge, but that will have to wait a little while. So what do you think? Water change or no? I can change out my mechanical filtration without doing a water change. I can do smaller water changes, but absolutely don't want to do water changes more than once a week. I'm surprised that my bioload is high. I figured with the water volume, I was doing pretty good. Even thought about adding a school of blue/green chromis.

 

[ndrwater]

Using API Master Reef Kit. Never thought of testing the new water before water changes. I use Instant Ocean Reef Crystals. Do you think that makes a difference? I intend to replace the wet/dry filter with a sump with a fuge, but that will have to wait a little while. So what do you think? Water change or no? I can change out my mechanical filtration without doing a water change. I can do smaller water changes, but absolutely don't want to do water changes more than once a week. I'm surprised that my bioload is high. I figured with the water volume, I was doing pretty good. Even thought about adding a school of blue/green chromis.

It's not that you have a ton of fish, it's that tangs are poop factories. And... Subsequently, Nitrate factories.
As for the test kits, there are definitely more accurate kits available. Salifert and Red Sea come to mind right away as better options.
The reason for testing the water before you add it to the display is to confirm or deny any possibility of your source water being the issue regarding cyano or any other nusance algae. Cyano isn't really an algae, but I digress...
I would also reccommend doing whatever maitenance that keeps you doing it. Adding to your routine will potentially make you not want to do it, and ultimately make things worse.

 

[Auquanut]

I've decided to go ahead and do a 30 gallon water change tomorrow. I'll test the new water first. Going to have to go online and order new media for the RO/DI and I guess I'll order a different water test kit. I use Salifert for magnesium testing. It seems to be cheap and effective. Any reason I shouldn't use Salifert for all of the other parameters?

 

[ndrwater]

Any reason I shouldn't use Salifert for all of the other parameters?

No reason at all. Salifert makes a good, accurate and reliable kit.

 

[Auquanut]

Thanks for the advice. Anything else you all can recommend to keep the tank going strong until I can upgrade the sump would be appreciated.

 

[lion king]

Have you checked your phosphates, everytime I've had cyano it's been because of an imbalance between nh3 and po4. Nitrates at 20, it doesn't take much po4 to cause a problem. I agree with crabs, check your water source for po4. As far as how long to store your water, you should check your ca, alk, and mg; these elements will precipitate when storing. Most premium salts recommend using right away after the water clears and is at temp.

If po4 is your problem, using gfo or another po4 reducing method will be your next move.

 

[brandon429]

This type of reef shouldn’t have a sandbed or if one is there, it’s cleaned well enough that it can’t cloud and be the secondary cause of nitrates behind the fish load and feed.

If there is one, that’s central zone of issues I bet, indicated by how much clouding would result if you reached in and grabbed sand and dropped it down

 

[Auquanut]

I run the BRS dual reactor. po4 is undetectable with the API test kit. I'll be upgrading to Salifert soon. One other thing. I've been doing alot of research. I have over 100 lbs of live rock in the DT. Some of the articles/forums/videos suggest that I probably don't need the bioballs in the filter at all. If I kept the polyfill for mechanical filtration and did away with the bioballs, does anyone think that could have a positive effect on nitrates? Still planning to upgrade to a sump with a fuge, but I'm not able to do that right away.

 

[brandon429]

Removing bb will not lower nitrate, it's sinked elsewhere + the fish and feed

mixing Bioballs around won't cause clouding, they're bioslick biofilm machines but they don't contribute to waste in a tank I say they're ok

 

[Auquanut]

Didn't think that removing the bioballs would lower nitrates. It's just that virtually everything I've seen calls them nitrate factories. I just thought that by removing them and allowing the skimmer, live rock and sand to process nutrients, there might be less nitrate that is not converted to nitrogen gas in the first place. Just a thought.