Nitrates very low, but phosphates high?

[hannernanner]

Hey reefers!
Did a little water testing this morning and found something kinda weird. My tank is fairly new, been running about 6 weeks now. My nitrates have been hovering around 2-3ppm, and until today my phosphates had been .02-.03. Makes sense, there isn't much in my 130g tank yet. I have a few snails and a clownfish. I feed a small amount (about half the size of my pinky nail) frozen food twice a day. In the morning it's spiraling brine shrimp + pe mysis, in the evening its Rod's food. I dose phyto daily and have a healthy pod population. I did a water change two days ago. Phosphates before change were right at .02. Checked the RODI water, its at 0TDS.

Today, Nitrates tested 2ppm and Phosphate was almost .1! Any idea why my nitrates would be so low, but my phosphates high? And that seems like quite an increase especially just after a water change. The only other thing that's changed in the last couple days is that I've extended my photo period from ~7 hrs to 9 hrs to prepare for my first corals. I know I could run GFO, I'm more interested in the "why" here since my goal is a balanced system.

 

[nereefpat]

Did you take the sample right after feeding or dosing?

 

[hannernanner]

Did you take the sample right after feeding or dosing?

About two hours after feeding this morning.

 

[southerntnreefer]

Phyto maybe driving it up? While the pods are there to eat it, theres no coral or any other organisms to take it in? My nitrates are just about undetectible, but my phos was .14 last week. I stopped the phyto dosing a couple weeks ago, and per natural growth of cheato im down to .083. Just a thought?

 

[brandon429]

question

I have handy several posts showing all common color chart nitrate kits disagreeing by as much as fifty ppm off a given sample

even if someone states they have the best tester, we still find massive difference such that we don't even know which one is best because nothing is calibrated against them such as a digital read...would we make changes here knowing that issue/curious

Ive been wondering this on nitrate posts lately

we're all operating within a huge range of the actual readings. what if your reading is 50 ppm higher or lower than what it really is? how would we know

I think we need a work thread where people compare kits off their tank sample and we re check the reportings for streamlining vs all over the place

 

[blasterman]

Agreed on test kits. However, the common salifert kit is pretty reliable at indicating the common 5-10 nitrate range.

.01 phosphate is only an issue if your nitrate bottoms out or you have algae problems. However, it's the progression that's concerning. Feeding meatier frozen food might help the ratio.

 

[Treefer32]

I make my home made frozen food with selcon, max aminos, and nori, and other nutritional items for fish and corals. I feed about 1-2 oz of this food per day for 16 fish, three of which are larger 8-10 inch tangs in my 340g display. The tank is two and a half years old. My nitrates test between 15-20 ppm within acceptable ranges. I run an algae turf scrubber that consumes phosphates and nitrates weekly. My phosphates are testing at .52. Way higher than what my nitrates test at.

I truly believe it's food. Even if the fish consume 99% of it. Mine do, they spit out shells and casings of the people shrimp I use (yes it's raw shelled shrimp, but there's some part of it they don't like. They chomp the meaty parts then spit out the rest. )

They poop alot! I'm amazed how much my large tangs poop! All that becomes phosphates.... I don't run a skimmer so it's left to decay or be consumed by the algae scrubber. I'm running 200 micron filter socks that I change daily and 25 micron cannister filter that I replace the cartridge with a clean bleached cartridge every three weeks. Pretty much anything organic breaks into phosphates... It doesn't take much it seems. I'm removing a lot with my scrubber. A softball sized ball of hair algae every 6-7 days. I don't know if it can produce any faster. It'd be interesting if I had hair algae every 3 days instead of every 6!