Please help me understand

[Dhoggs]

Before I go on with my question, I would like to provide a brief description of my system. My current system(125 gal total water volume) has been up and running for 4mos now. The rocks were cured for 7mos, I bought new sand and the initial water came from my old system. I did not use the rocks and sandbed from the old system as I did not want to stress my livestock/corals while the new tank cycles. I run filter socks which I replace every 4th day, skimmer (Vertex Alpha 200), 1/4 cup of gfo and a chaeto in my refugium. I feed 1 cube of frozen brine shrimp, 1 cube of frozen mysis and 2x rotation of pellets via AFS daily.

Initially the nitratr was undetectable so I dosed KnO3 2 weeks ago which brought my nitrate up to 2-3ppm (via redsea pro test kit). I tested every other day since then and the level didnt change.

My question is, why does the nitrate level not go down 2 weeks after I dosed. Could some of the nitrate come from what I feed the tank?

2nd question is....with the amount of food that I am feeding the tank, why does the PO4 level stay at 0ppm (via Hanna Phosphorus ULR). Should I take my GFO offline?

I do see some cyano growing on the sandbed and I have to clean the glass once a week due to film algae. Rocks in the DT are pretty clean. Chaeto in the refugium barely grows.

I would like to add that I do 1 gal/day water change via AWC and most of my corals/frags are sps.

Any suggestions or recommendations on how I can bring balance to my system will be greatly appreciated.

 

[Dhoggs]

Tank is 4mos old. All livestock and frags came from my old tank.

 

[Adam G]

Yes, the nitrates are coming from what you’re feeding. If you rose nitrates to that level via an additional outside source and continue to feed the same you are really experiencing the ideal balance of nitrates maintaining slightly elevated levels right where you put them with an additive. Of course if levels go up then you would want to dial back you’re feeding a bit.

Your tank looks great. You are doing everything by the book with your auto water changes, refugium, and large skimmer. In regards to phosphates, nitrifying bacteria need phosphate and Nitrate to metabolize and grow. You are running out of phosphates(level at zero) before nitrates (still detectable) and your bacteria culture is now limited by no phosphates. If you ask me that is ideal. You can raise phosphates by removing GFO or feeding more or dosing phosphates. However, nitrates at .02 and undetectable phosphate to me is ideal. Phosphates too high cause me big problems.

Sounds to me like you are as close to balanced as I have ever achieved. I would just feed a touch more to get detectable phosphates if possible but that then comes with its issues as well such as undesirable algae. At 4 months old your tank seems to be maturing nicely. I would say very tiny changes now and more time for bacterial cultures to mature and diversify is right wher you should be. I chased numbers and imbalance on this build for the first year and my tank suffered for it.

 

[Flippers4pups]

Nitrate most certainly can come from foods, as does some phosphate.

The tank will find a balance biologically, consuming the foods and producing wastes that get broke down. Excess of these end up in the water collum as N03 and P04. Having more N03 than P04 is desirable. You have P04 in the water, it's just that the test kit can't read it and it's being consumed faster than being able to build up to detectible levels.

 

[Dhoggs]

What I’m gathering is I should not make any changes at the moment and let my PO4 lvl stay where it’s at? I was actually thinking of dosing PO4 to bump it up a bit but have not done it yet as I do not know what to dose.


Btw...Thank you all for sharing your knowledge.

 

[Flippers4pups]

What I’m gathering is I should not make any changes at the moment and let my PO4 lvl stay where it’s at? I was actually thinking of dosing PO4 to bump it up a bit but have not done it yet as I do not know what to dose.


Btw...Thank you all for sharing your knowledge.

For a tank that young and seems to have balanced out, I would let it ride. Nope, no changes.

I run around 15-20 ppm N03 and at times undetectable P04, with the amount I feed, I know there's plenty of P04 there somewhere.

Just a note, just because my system can handle elevated N03, doesn't mean everyone else can. Just want to make that clear.

 

[SashimiTurtle]

Your tank looks great, corals are colorful, sand is clean. It appears to me you've found equilibrium. I'd keep doing the same thing. Testing 0 phosphates doesn't mean they aren't there. They are just being used up as they are being released into the water. Perfect balance.

 

[Dhoggs]

I guess I’m now in the most difficult stage of this hobby....not changing anything and letting the tank take its course.

For the first 3 months, I have spent so much time tinkering, working on “projects” to make my system run with the least human intervention so when the time comes, I can spend more time looking closely at the tank and it’s inhabitants and of course spending more time with my family (<—- my wife sometimes visits these forums). I guess that time is now.

Once again, I appreciate all the help! Thanks!!!

 

[Flippers4pups]

"I guess I’m now in the most difficult stage of this hobby....not changing anything and letting the tank take its course."

Yep, that"s the idea! Test your water and record it, do your weekly maintenance and sit back and watch it grow!

 

[Dhoggs]

Exactly my thoughts, that's why I wanted to know how old the tank is, everything you describe is new tank syndrome, all to be expected , tank looks good, keep tracking the big 3.

Will do...besides the weekly maintenance routine (clean glass, filter sock change , refill ATO reservoir and empty skim-mate container) I will leave it be.

I use to check the my parameters daily but after the CaRx was dialed in, I now only test once a week.

Thanks!