ULN tanks (Zeovit System for example) and PO4, NO3 values

[Bramzor]

I'm running the Zeovit System which is an ULN system but till today, I'm still not sure if a value of 0 for PO4 or NO3 is an actual problem.
I would assume not but you read many times that 0 values causes issues.
So I wonder, is this a problem because corals will die if PO4 and NO3 are at zero for a longer time or is it more because it might cause issues like dinos?

 

[Nano sapiens]

1. '0' readings just tell you that the level is 'undetectable' by that particular test kit and the level is quite likely not really '0'.

2. Our hobby grade test kits only test for inorganic phosphate, not organic. So, the level of actual phosphate in the system is higher (an ICP test will show both).

3. In nature on a healthy pristine reef, both phosphate and nitrate are very low (what we would see as '0' or 'near '0') on a hobby grade test kit), but food availability is much higher than we typically provide in a reef tank. The Zeovit system tries to emulate that very pristine low nutrient water quality, but has to some how make sure that the coral are getting enough nutrition in order to stay colorful and healthy. The system relies largely on providing bacteria to keep nutrients very low as well as providing coral nutrition (bacteria are one of the photosynthetic coral's natural foods along with by products derived from it's zooxanthellae's photosynthesis and zooplankton and/or phytoplankton).

To answer your specific question, corals can actually die if NO3 and PO4 levels are kept extremely low for a longer period of time without supplemental feeding. Corals have 'fat reserves' like other animals in the form of lipids, but once the reserves are gone they will be in dire straights if they can't replenish their energy reserves (by products from photosynthesis alone are not enough).

Many reefers report that keeping 'undectable' levels have allowed dinoflagellates to bloom since they typically out compete other organisms in very low nutrient conditions. However, having low NO3 and PO4 levels doesn't guarantee that you'll have dino blooms, just can make it more likely (especially if the system doesn't receive regular feedings which allow competing/predatory organisms such as microalgae, amphipods, worms, etc., to flourish).

 

[Crustaceon]

Zeovit is an oddball among reefing practices and like any other reefing methodology can be very successful if you really stick to it. While low nitrates and phosphates come with the territory and is the goal of zeovit, I wouldn’t really consider it a typical ULNS simply because so much is continually and religiously added back in specifically to feed coral and bacteria. With a typical ULNS, we strip the tank of nutrients (sometimes over strip) and hope what we feed our fish and squirt in front of our corals when they start looking bad is going to be enough and not fuel algae instead.

 

[Sharir]

In my opinion I don't think that keeping "0"level of Nitrate and phosphates are healthy for the reef tank because :
NB:I am referring to totally 0 which can only be determined by an icp test

1)the corals that we keep in our systems come from all parts of the world (ie. Australia ;Fiji;Indonesia etc.) this means that there are various different types of environments which they are found some corals come from higher Nitrate and phosphate regions than others. So it really depends on what tank type you have (what corals you" mainly " keep in your system) for example if you keep a chalice coral in a zero Nitrate and phosphates environment, it will eventually die or at minimum be very stressful for the coral.

2) in the wild the corals on the reefs are constantly recieving food (feeding) from zooplankton and phytoplankton through the whole day (especially night when feeding tentacles of the corals extend) this provides a reliable source of energy to the coral. In reef aquaria that food source is scarce and sometimes non-existant.

3)the corals which generally like the ULNS environment are from the reef crest area of the natural reef so, I would say that an Acro dominant reef tank would be a perfect fit for the ULNS approach.

 

[Randy Holmes-Farley Verified Community Expert]

In nature, and in many ULNS systems, corals get N and P from other things (that are dosed) than nitrate and phosphate. That makes these being lower more acceptable.

 

[Bramzor]

In nature, and in many ULNS systems, corals get N and P from other things (that are dosed) than nitrate and phosphate. That makes these being lower more acceptable.

So basically NO3 and PO4 tests can be forgotten if using something like Zeovit as you dose N and P (while NO3 and PO4 can be zero almost all the time?) So I should start trying to "read" my corals to see if nutrients are at an acceptable level?

I switched over from another system where zero NO3 and PO4 was a no-go which always caused issues for me as my system just does not want to keep these levels without growing algae all the time. So still have to adapt to the mindset that these values are just fine and that these will be replaced by added N and P that are dosed daily. Started dosing Tropic Marin NP Plus but these are also mostly organics so testing would not show much anyway.

Just do not want to get zero N and P which could cause corals to die and although I really like Zeovit, I'm not sure which products hold N and P. My guess is that Zeofood is a combination of items (including amino acids) which is a form of N right? As amino acids can be a way to raise NO3 levels?

 

[RudyVH]

I'm running the Zeovit System for quit a time , No3 en Po4 can be controlled by fish food and amino supplementation , i'm running No3 = 3 and Po4 = 0.03 for a long period now , just keep in mind that this practise must be closely controlled .

Acropora growth and color is better now than before on ULNS ?