Nitrate reduction

ReeferMadne55 · Jul 8, 2020

I have a order of fish and some zoas coming in tomorrow night. Just tested all my parameters on the tank and I have a few questions.

Salinity: 1.0245
Temp: 78 F
Ammonia: 0 ppm
Nitrite: 0 ppm
Nitrate: 20 ppm

I kinda wanna get my nitrates lower before the fish arrive. I did a 30% water change literally yesterday. I was wondering if I can do another 40% change tonight? Is that too close together?
I figure if I do another 40% tonight I could get my nitrates around 10 ppm, which id personally feel more comfortable adding fish and zoas at that level.

PatW · Jul 8, 2020

You should be fine assuming.....

that you are using the same salt mix and the quality control is close enough that the major parameters match,
that the salinity is close,
and the temperature is close.

You can make really huge water changes safely. If you think about it, any new fish or coral you get undergoes a virtually 100% water change and in that case the parameters are probably farther off than you home system is from you newly mixed water.

andrewey · Jul 8, 2020

Go for it- so long as you do the water changes properly (matching parameters), you can do 100% water change if you really wanted to

. The larger the water change, the more you should match your parameters to not harm any animals in the tank. If the tank just has live rock, you need not worry too much

ReeferMadne55 · Jul 8, 2020

Okay I can do another big change tonight then. Could doing large changes so frequently stress out my current fish at all?

andrewey · Jul 8, 2020

The frequency is really not important- it's going to be the parameters of the water (e.g. temperature, salinity, pH, etc.) that could cause shock and harm the fish if the change is large enough. If these parameters are matched, you need not worry.

ReeferMadne55 · Jul 8, 2020

Okay awesome, if I get the nitrates to 10 is that an acceptable level for zoas and Vargas Cespitularia? Just started dabbling in coral a bit so I have a lot to learn

andrewey · Jul 8, 2020

10 will be fine for those two. I don't want to overly complicate the situation, but generally speaking, both corals will grow well in a range of nitrate levels, so I wouldn't sweat it too much (if we're really being honest, they would probably prefer a nitrate of 20 vs. 10, but pretend I didn't say that

). In truth, what's more important than anything is that your corals have stability. If you are planning on having a mixed reef and you feel like 10ppm nitrate would be your ideal range, I would go there and try and maintain it. In broad brush strokes, many soft corals prefer "dirtier" tanks, which is to say tanks with higher nutrient levels. The downside to this is that you have to balance nuisance algaes at this higher level. Therefore, it's a bit of a balancing act of growth vs. algae with these species and the overall level will be influenced by your nutrient export, tank maintenance, clean up crew, etc.

ReeferMadne55 · Jul 8, 2020

andrewey said:
10 will be fine for those two. I don't want to overly complicate the situation, but generally speaking, both corals will grow well in a range of nitrate levels, so I wouldn't sweat it too much (if we're really being honest, they would probably prefer a nitrate of 20 vs. 10, but pretend I didn't say that ). In truth, what's more important than anything is that your corals have stability. If you are planning on having a mixed reef and you feel like 10ppm nitrate would be your ideal range, I would go there and try and maintain it. In broad brush strokes, many soft corals prefer "dirtier" tanks, which is to say tanks with higher nutrient levels. The downside to this is that you have to balance nuisance algaes at this higher level. Therefore, it's a bit of a balancing act of growth vs. algae with these species and the overall level will be influenced by your nutrient export, tank maintenance, clean up crew, etc.

Oh interesting so I plan on keeping softies and sps, the light I have wouldn’t be outstanding for sps. So where should I try to keep the nitrates at then?

Uncle99 · Jul 8, 2020

Nitrate 2-20ppm
Phosphate 0.03-.2ppm
It’s more than meeting a “number”, find what you system can do, where do nutrients like to sit.
Stability rather than chasing any number will bring better results.

Example, if my nitrate on a consistent basis is 20 or less, I’m ok with just maintaining.

As a reference point, This DT has run 35 month with nitrate at 15-20ppm and phosphate at .15ppm.

andrewey · Jul 8, 2020

That's a really complicated question. The first thing to realize is that when people compare nitrate numbers, they often are comparing apples to oranges. I don't want to overwhelm you, but suffice to say, not all discussions of nitrate are equal- one person running a tank at 2ppm nitrate does not mean others could run their tank successfully at 2ppm nitrate. The same is true for someone running a tank at 100ppm nitrate.

For example, I was previously running my nitrate around 5ppm, but due to dinoflagellates, I had to increase that number. I now run that tank at 25ppm nitrate and couldn't be happier. I have also run tanks at 1-2ppm nitrate and other tanks that were easily at 100ppm nitrate and in all cases, I am my coral were exceedingly happy. I'm obviously holding back from discussing phosphate, nutrient availability, and the age of the tank. All this is designed to say, that while there are many ways to skin this cat, 10ppm seems like a reasonable starting point

I would focus on stability above all else at this level. Once you are able to keep a stable tank (pH, alkalinity, salinity, temperature, etc.), you will be in a better place down the road to slowly experiment with different nutrient levels.

A lot of people will end up throwing out "ranges"- these are good rules of thumb, but many successful tanks are no where near these ranges. Therefore, they are good places to start, but as you gain more experience, you'll find all of the puzzle pieces are more important than the single values we assign to individual parameters.

ReeferMadne55 · Jul 8, 2020

Thanks that explained it really well actually

blasterman · Jul 8, 2020

My issue here is you have high nitrate and are adding live stock and want to lower it. The equation doesnt add up.

Water changes just temporarily lower nitrate. Unless you've just cycled a tank and it has no bioload in it nitrate will just go back up. You need to fix the problem and source of the high nitrate because the additional fish will make it worse.

I agree with Uncle99 in the long term but respectfully disagree in the short term. Young tanks dont have the coraline covering nor large LPS or SPS colonies to compete with nuisance algae. Nitrate at 20 and P04 at .15 is a bomb waiting to go off in a young tank. Get ready for algae and likely cyano an inch thick.

I have to added nitrate and phosphate to my fast growing SPS tanks, but they are long established and algae cant compete. If I ran nitrate up to 20 when they were two months old they would look like a swamp. Always start at minimal nutrients with younger tanks and slowly let them slide upwards as they mature and you dont see issues.

ReeferMadne55 · Jul 8, 2020

blasterman said:
My issue here is you have high nitrate and are adding live stock and want to lower it. The equation doesnt add up.

Water changes just temporarily lower nitrate. Unless you've just cycled a tank and it has no bioload in it nitrate will just go back up. You need to fix the problem and source of the high nitrate because the additional fish will make it worse.

I agree with Uncle99 in the long term but respectfully disagree in the short term. Young tanks dont have the coraline covering nor large LPS or SPS colonies to compete with nuisance algae. Nitrate at 20 and P04 at .15 is a bomb waiting to go off in a young tank. Get ready for algae and likely cyano an inch thick.

I have to added nitrate and phosphate to my fast growing SPS tanks, but they are long established and algae cant compete. If I ran nitrate up to 20 when they were two months old they would look like a swamp. Always start at minimal nutrients with younger tanks and slowly let them slide upwards as they mature and you dont see issues.