high phosphate level but low nitrate

[hvusalt]

the test results don't make sense to me.

120 fish only with lots of live rock
50 g sump with live rocks and lots of chateo
good size skimmer
UV number 3
salinity is 1.024
medium bio fish load

phosphate level is 5.0 (i did the test two times) but nitrate is only less than 5.0.? to me normally high phosphate level results in high nitrate level too- noted this tank doesn't has much algae with white sand bed and clear glass. i feed my fish 3 times per week and recently do 20% water change weekly. do i have to add the phosphate reactor to reduce the phosphate? high phosphate level effects to fishes? the tank has low light due to fish only, is that low light effect phosphate level?. noted i tested the other tank with a very good result 0.5 and this tank has phosphate reactor.
any inputs are appreciated

 

[drsalomon]

Phosphate level of 5 is really high. Fire up the gfo reactor!

 

[mbian112283]

I have the opposite. I am running bio pellets and think phosphate has become the limiting factor in my tank.

Maybe you don't get algae is due to light and their isn't enough nitrate for it to grow.

 

[hvusalt]

it makes sense on the algae but i dont know why the phosphate level is so high? may be too much food and waste? noted i got this tank couple month ago from a guy who started up this tank more than 5 years ago.

 

[mbian112283]

Did you use new sand? Phosphate could be leaching from the sand or live rock.

 

[myram]

Old test kits?

 

[JasonandSarah]

Correct me if I'm wrong but if there's no algae or negative effects caused by the phosphates is it a big deal? Fowlr shouldn't really worry about phosphates unless it's causing unsightly issues correct........
If it was a reef tank we'd be in a different stratisphere

 

[this is me]

What kind of test kit are you using and have you verified the test with another brand.
I agree with Jasonandsarah that in a fish only tank, why care? If anything, the algae is good for the fish to graze on.
You also want to test your freshly mixed salt water to see if the water or salt you're using is contaminated.

 

[hvusalt]

i have other tank and i tested both to compared the results so i know it is not about test kit. the result was corect. i may fire up the GFO reactor tonite and see if it helps. the sands and rocks was there once i took over the tank from the guy so i dont know how old for these. i am curious about the water elements now cause some point i will start adding corals in. is that a good idea to do a 90-100% water change to start fresh?

 

[delta]

With a tank that old it is possible you have phosphates leaching out of the LR. But I would get a second set of eye and test kits on your water sample.

 

[delta]

i have other tank and i tested both to compared the results so i know it is not about test kit. the result was corect. i may fire up the GFO reactor tonite and see if it helps. the sands and rocks was there once i took over the tank from the guy so i dont know how old for these. i am curious about the water elements now cause some point i will start adding corals in. is that a good idea to do a 90-100% water change to start fresh?

the water change will reduce phosphates a percentage based on the amount of water you change. But if it is leaching it will rise until the phosphates are reduced to a point the tank is balanced and maintaining them on its own.

It won;t be a fresh start but will help in the long run. I wouldn't go over 50% of the water volume but that is jsut me.