SPS: Low Nitrates, Dosing and Cyano

[fishface NJ]

I have 40B with a 40B sump. 90% of the tank contains SPS. I have a few SPS that have good color and some are pale. 50% of the rocks came from my other tank 2 years old and the other 50% are live rocks purchased from KP Aquatic shipped in water purchased back in Jan. Sand is 2-3 inches deep. I have had good growth. I have an over sized skimmer that was supposed to be used on my 75 or 90 gallon tank but that has not happened yet. 5 fishes that get fed twice a day heavily.


My tank always reads 0 nitrates and 0 phosphates. There are no nuisance algae outbreaks. I will get a small amount of cyano the day after I dose Sodium Nitrate or live phyto. I can usually get the nitrate to 1 by dosing sodium nitrate. If I try to dose two days in one week there will be cyano on 20% of the rocks and on 30% of the sand. I usually see some improvement in color by day 4 after the second dose of sodium nitrate. I normally only dose once a week because of the cyano problem. Cyano will disappear if I don't dose Sodium Nitrate or phyto for 2 weeks. I haven't used Chemiclean because it will cause other problems with tank.

My question is how to I proceed?

 

[Spare time]

I would stop using the skimmer.


Also, hypothetically, cyano shouldn't necessarily get a boost from the nitrate dosing as they are able to fixate nitrogen from the atmosphere.

You could also feed the sps a mix of reef chili, baby brine (my favorite for sps), or other planktonic foods daily.
That way they can get their nitrogen from foods rather than the nitrate in the water column.

 

[fishface NJ]

I would stop using the skimmer.


Also, hypothetically, cyano shouldn't necessarily get a boost from the nitrate dosing as they are able to fixate nitrogen from the atmosphere.

You could also feed the sps a mix of reef chili, baby brine (my favorite for sps), or other planktonic foods daily.

I could go for example two weeks and not dose (either sodium nitrate or phyto) but when I do, I will 100% have cyano. I dose only at night and when I wake up the next morning there is cyano in the tank. No other time will cyano show up.

I do feed reef chili once a week

 

[Spare time]

I could go for example two weeks and not dose (either sodium nitrate or phyto) but when I do, I will 100% have cyano. I dose only at night and when I wake up the next morning there is cyano in the tank. No other time will cyano show up.

I do feed reef chili once a week

Personally I would do the reef chili once a day in this case

 

[fishface NJ]

Personally I would do the reef chili once a day in this case

Wouldn’t that only just raise my phosphate?

 

[VR28man]

I would stop using the skimmer.


Also, hypothetically, cyano shouldn't necessarily get a boost from the nitrate dosing as they are able to fixate nitrogen from the atmosphere.

You could also feed the sps a mix of reef chili, baby brine (my favorite for sps), or other planktonic foods daily.
That way they can get their nitrogen from foods rather than the nitrate in the water column.

Random thread digression: I recall there are studies that pocilloporids will eat the baby brine, but the question was up in the air for acros.

Do you have strong reason to think your acros eat the baby brine? Just curious because if so I'd definitely do so.

 

[VR28man]

Also, @Bulk Reef Supply 's videos are usually pretty good (but I'd never take them or anyone else as The Literal Truth - except Randy when it comes to chemistry. ) and this I thought is especially good:



During any of these phases, to include phase 1, I'd also remove the cyano by hand (brush if it's on the rock) supplemented by a vacuum mechanism, as much as possible. But IME a small effort will get 80% of the cyano, while the next 10% will take 10x the effort and the final 10% like 50x, so I might stop after I get the low-hanging fruit.

Ryan repeats the longstanding mantra: it took weeks/months to get to this phase, it'll take weeks to solve it, and nothing good will happen quickly.

Also note that if he didn't say it directly, he at the very least implies that if you don't have phase 1 down, phase 2 and 3 won't be effective in the long run.

 

[Spare time]

Random thread digression: I recall there are studies that pocilloporids will eat the baby brine, but the question was up in the air for acros.

Do you have strong reason to think your acros eat the baby brine? Just curious because if so I'd definitely do so.

This one mentions some species capture and eat it https://www.tandfonline.com/doi/full/10.1080/03946975.2015.1119006

There are a few others I saw too that mention feeding some acropora species baby brine.

 

[Spare time]

Wouldn’t that only just raise my phosphate?

It could raise both depending on how much is eaten, but you don't have an excess phosphate or nitrate issue. The idea is that you mimic the way corals get their nitrogen and phosphate in the ocean where nitrate and phosphate are very very low compared to reef tanks.

 

[ScottB]

Never dose nitrate when PO4 is reading (Hanna) zero. Always dose up PO4 first and dose it extremely liberally. 24 hours later it will be zero again if you were actually depleted. Keep going with PO4 and avoid NO3 dosing until you can keep a PO4 reading. Again, if you are really PO4 depleted (Hanna) ignore whatever cyano is happening and focus first on measurable and stable PO4.

Once you have that, then slowly start dosing NO3. Your PO4 will likely fall so don't let that happen.

This is all about the bacteria populations in our closed systems that help us process the excess and feed the coral in that process. We don't REQUIRE a ton of excess, but some must be continually available.

 

[BroccoliFarmer]

Are you running macro algae in your refugium? I was having problems very similar that all of my levels were hitting zero. Now I do my little dosing and I spread my dosing out throughout the day. I run my photo period on my cheato between 12AM and 6AM I have a mixture of 1500 ML of RO water, 3 tablespoons of Potassium Nitrate and 1 Teaspoon of Trisodium Phospate and I dose about 2 ML every two hours (on average) and my nitrates hover around 5 and phosphates around .25 using the API kits. It took me about three weeks to stabilize and zero in..but tank be happy. I am nudging up the dosing a little every couple of days when I see that my levels are a little low but by putting in a constant low dosage...dinos and algae are staying away and no cyano.

 

[VR28man]

This one mentions some species capture and eat it https://www.tandfonline.com/doi/full/10.1080/03946975.2015.1119006

There are a few others I saw too that mention feeding some acropora species baby brine.

Ah yes I remember that one. A millepora, P damocornis are very common in the hobby, so it's very good info.

 

[ReefEco]

I had good success in fighting cyano when my 600g system was set up new - using a combination of Brightwell's Clean and Vibrant, plus Red Cyano Rx. You likely have significant cyano already in your system, which is why it is able to appear so quickly when nutrients are available for it. It is one of the larger myths in the hobby that cyano appear because you have no or low nutrients - they uptake nutrients, as you are seeing. I would try the outcompete route with some better bacteria products, inch up your nutrients as you are able to. If you do get small amounts of cyano at first, I would keep going despite that and stabilize nutrients at higher levels with other bacteria to out compete the cyano. I've used Blue LIfe's Red Cyano Rx on the whole system, dosing twice, with no ill effects with fish or corals. My tank took about 3 months even with the treatment and bacteria to stabilize, with nitrates about 7 and phosphate about .03, so it does take some time. Good flow will help with cyano as well...