Where is my phosphate coming from

[tmcpeek]

I lost a fish in my Qt this morning so I tested the water. The qt has been cycling for 5 weeks and nitrites and ammonia are 0 and nitrates <5. I added 7 green chromis two days ago and have lost 2 already (they are in a container being acclimated to my main right now)

I tested phosphate and here are the readings
QT 3-4
display 0
R/O D/I water 0
fresh batch of mixed salt water 0

The Qt is bare with the exception of 2 pieces of PVC and a piece of granite rock (found at the beach years ago bleached it boiled it and rinsed it in r/o water and let sit for a week before putting it in the tank) The only thing I can think is that the rock is leaching phosphates so I removed it and will do a complete water change in the QT to see what happens.


Could it be anything other than the rock adding phosphates to my QT?

 

[quarryshark]

Don't worry about PO4 in a qt tank. What is important are your PH, ammonia and nitrite levels. Did you take them?
Also the granite does not need to be in the qt tank, bare bottom is better in case the need arises to treat.
If these fish are dying, please do not put them in your main. It could be a parasite that you do not want in there.
Also a proper qt period should be 4 weeks.
What are you other water readings and any symptoms that the fish may be showing?

 

[tmcpeek]

I will take the chromis back to the LFS today. I wanted to put them in the main because I thought it may be the phosphates killing them.

I figured the granite would be ok since it was not porous and had large holes in it for small fish to hide but I will leave it out now.

Here are my other readings
PH 8.2
Amm 0
nitrites 0
nitrates <5
SG 1.023

I am still puzzled as to where the phosphate could be coming from.

The fish when added were in a school then one would be a loner in a corner only to find him dead in the morning. This moring two were dead. Could it be that the larger ones are terrorizing them? I had two in my QT previously for 4 weeks and then added them to my main with no problems. Perhaps it is just a bad batch of fish the store received and they have something. Thanks for the response

 

[quarryshark]

Could be a bad batch of fish, or maybe something is leaching from the rock. What I would do is pull the rock, do a 50% water change, maybe run some GAC for a safe measure and put them back in the qt and continue the process.
Just monitor the water levels and do small water changes every couple of days.
PO4 should not hurt them. It may be the rock adding to it, or did you check your source water?

 

[steve-s]

Most likely the granite. PO4 usually goes hand in hand with granite. Easy way to tell is place the rock in a pail by itself with newly prepared SW and test after a week or so. Chances are high you will get a reading.

Cheers
Steve

 

[tmcpeek]

Thanks for the tips.

Yes I did check my source water and it was 0. Everything but the QT was 0 so I assumed it was the granite. I have it in a 5 gallon bucket now so I can test the levels in a week to confirm that was the culprit.

Also does it hurt to run phosguard if you do not have any phosphates. I have 3 filter cylinders on my lifereef sump and was going to run gac in one and denitrate in one and phosguard in the other. Will this be ok?

 

[steve-s]

Also does it hurt to run phosguard if you do not have any phosphates. I have 3 filter cylinders on my lifereef sump and was going to run gac in one and denitrate in one and phosguard in the other. Will this be ok?

If you mean the main tank, I would avoid this. Phosguard is an Aluminum oxide compound that can and will damage the zooxanthellae in corals. Sometimes even causing RTN is SPS's.

If you want something that can be used on a daily basis long term, look for an Iron oxide (ferric hydroxide) PO4 product or use a Polyfilter.

Cheers
Steve

 

[tmcpeek]

Thanks, is the denitrate and gac ok to use daily?

I found Phosban that looks like what you are recommending.

 

[steve-s]

Denitrate granuals are not very effective but it nor the GAC are harmful in any way, I also run carbon 24/7. The Phosban would be just fine.

Merry Christmas
Cheers
Steve

 

[tmcpeek]

Thanks Steve,

Do you recommend any particular gac?

 

[steve-s]

Not really, just avoid the cheaper grades as they are much higher in PO4 but they all are to some small degree. Personally I use Chemi-pure by Boyd but there are several goods ones available. Matrix, Black Diamond and a few others.

Cheers
Steve