my tank is consuming phosphates?

The_Skrimp · Jul 1, 2020

Hey folks.
So I have a weird noobie question for you all. My tank is about seven weeks old at this point. My cycle is definitely complete because my ammonia and nitrites are down to zero and my nitrates are low but still detectable using the API test kits. It's not quite as orange as 5.ppm on the test strips but it's definitely not zero either. I'm at the point now where I'm going through the uglies. I have some brown on my substrate and rocks. It's really not much but I was still a little worried about it because I at first I thought it might be Dinos. I'm now starting to think it's more likely to be Diatoms. The reason I thought it was Dinos at first is because I have ZERO Phosphates. It's the weirdest thing. Since cycling my tank, I've picked up two clowns and a clean up crew and I've been feeding a little extra heavy to raise the phosphates and nitrates so I can start getting coral but my phosphates just won't go up. I'm starting to think this has to be diatoms consuming the excess phosphates in the water but I don't know enough to make that conclusion.

Today I tested RO water as kind of a control and tested tank water to see if maybe the phosphates were just low but the weirdest thing is that my RO water actually looks a little bit greener than the tank water meaning the water from my tank definitely has less phosphates than the clean water I've been topping off with and doing water changes with. Any ideas what the deal is? Should I just be feeding heavier? Am I likely correct in my conclusion that I'm just having a diatom bloom right now consuming the excess phosphates?

Uncle99 · Jul 1, 2020

Phosphate is a challenge to measure as the amount is very small.
API tests are not sensitive enough to measure accurately.
If your adding foods, your adding phosphates, so they are there.
I use the Salifert test for phosphate, all I need to see with this test is any faint blue.
Hanna UL phosphorus test has the ability to test with more accuracy.

The_Skrimp · Jul 1, 2020

Thanks for the response. The only reason for the difference in the tests I did that I can think of is potentially the plastic bucket I keep my top off water in is leaching slight amounts of phosphate.

Keen4 · Jul 15, 2020

Salifert has a more accurate result for Phosphate testing in my opinion. And same here- New tank 5 weeks old and phosphates are high- so random. Not sure how. I just added my first fish two days ago.

Crustaceon · Jul 15, 2020

If you’re going to test phosphates, don’t bother with any test aside from a hanna checker. Everything else is trying to gauge shades of clear, which isn’t fun.

GregDaKeg · Jul 15, 2020

The_Skrimp said:
Hey folks.
So I have a weird noobie question for you all. My tank is about seven weeks old at this point. My cycle is definitely complete because my ammonia and nitrites are down to zero and my nitrates are low but still detectable using the API test kits. It's not quite as orange as 5.ppm on the test strips but it's definitely not zero either. I'm at the point now where I'm going through the uglies. I have some brown on my substrate and rocks. It's really not much but I was still a little worried about it because I at first I thought it might be Dinos. I'm now starting to think it's more likely to be Diatoms. The reason I thought it was Dinos at first is because I have ZERO Phosphates. It's the weirdest thing. Since cycling my tank, I've picked up two clowns and a clean up crew and I've been feeding a little extra heavy to raise the phosphates and nitrates so I can start getting coral but my phosphates just won't go up. I'm starting to think this has to be diatoms consuming the excess phosphates in the water but I don't know enough to make that conclusion.

Today I tested RO water as kind of a control and tested tank water to see if maybe the phosphates were just low but the weirdest thing is that my RO water actually looks a little bit greener than the tank water meaning the water from my tank definitely has less phosphates than the clean water I've been topping off with and doing water changes with. Any ideas what the deal is? Should I just be feeding heavier? Am I likely correct in my conclusion that I'm just having a diatom bloom right now consuming the excess phosphates?

It's a very young tank. Let it ride a few more months. Just do normal water changes. It will
Settle out and then you can worry about that. Save up for some good test kits (cheaper than coral loss)