Help me understand stability.

[Greg B.]

Help me understand nutrients stability.my tank is currently 2 years old. I have a 40br with about 10 gals inside my sump. I run 2 50 micro filter socks and a 100micron I change all 3 every week. I do a 10% waterchange every Sunday and a 20% on the 4th Sunday. I have a refugium with chaeto as well as a oversized skimmer that does a good job. I have no issues keeping the main parameters stable alk mg and cal. But I have a hard time keeping my nitrates and phosphates stable. Currently my nitrates are about 4.3ish but my phosphates are .13. I get large fluctuations over the course of a few weeks in my phosphates and nitrates. When my chaeto is really growing it will bottom them out. I tear off some chaeto and it will shoot back up.but I want to understand the stability part of it because I feel like stability means staying inside a certain number. Also with phosphates I want to run a gfo reactor. But I am unsure how to get stability out of it. Do you guys run yours for a period of time and shut it off? I can grow coral pretty good. Monti cap digitata zoas platygyra acans no problem. But I want to get into some acro. I've bought tons over the years. None have survived.

 

[rishma]

How big a fluctuation are you seeing?

I keep what I consider extremely stable phosphate and nitrate but it does vary some. I can even see a repeatable variation based on time of day with phosphate. While I aim for stability, I don’t actually think variation within a target range is an issue.

I find GFO is a useful tool to correct high phosphates but I have not had success achieving stability with continued use.

Your stated nitrate and phosphate levels are good in my opinion

 

[Lasse]

If your nutrients vary because of your amount of Chaeto - why you do not try with exporting some smaller amount of Chaeto every day? Just adjust your biomass of Chaeto to the daily input of nutrients. As it now - when it growing good (high biomass) your Chaeto consumption of nutrients is higher than your input - when you harvest a bunch (get a low biomass) - the new biomass of your Chaeto consume lesser of the nutrient input.

Sincerely Lasse

 

[Mr. Mojo Rising]

the phosphate level is not high, I would just use liquid phosphate remover at this level. A few drops is all you'll need to drop it below .1

 

[Reefer911]

Try cutting back on the water changes.

But I think the cheato is the culprit here, as Lasse pointed out.
You might have more stability without cheato altogether, maybe with the addition of more bio media like a genesis rock, and keep the current WC schedule

 

[Randy Holmes-Farley]

I see no reason to use GFO unless phosphate is far higher than 0.2 ppm.

I’m not sure there’s much evidence that stability in nutrient levels is needed or even useful, as long as the levels do not get too low.

 

[Lasse]

I supose you feed the same amount of food each day - it means that your input of nutrients is constant. Of the nutrients some will end up in the fish and other animals. Their biomass will grow and a higher biomass - more of the nutrients will be taken up and more feed is needed. But its a slow growth - maybe a biomass double time of several months or more. The chaeto will take up from the pool of nutrient that will end up in the water but the optimal double time for their biomass is short - from some days to a week. It means that (for each doubling of the Chaeto biomass they will double their uptake of nutrient - after a while when your biomass of Chaeto is large enough - they will consume more nutrients than will be put into the system as food. - You bottom your nutrients. The trick is to harvest so much and so often that your Chaetos biomass uptake balance the input of nutrients.

But I agree - your nutrients is far enough and I also doubt the total stability doctrine and I also agree that zero or near zero is more dangerous than the opposite (to high concentrations)

Sincerely Lasse