High phosphate in a newly cycled tank.

assad319 · Dec 6, 2019

Hi all. I have gone through the cycle of my tank which has taken around 6 to 7 weeks.

The tank was set up by someone who was supposed to be experienced in reef tanks but he set up the tank with dead rocks. Had I known what I know now I probably would have just paid extra for live rocks.

Anyway, I introduced a CUC last week and planned on introducing one or two fish and a soft coral. I carried out testing of all the crucial readings and noticed that my phosphate was about 2! Nitrate was 25. Algae has also increased significantly.

I have tonight carried out a 20% water change and added some Rowa phos into my rear sump media area after some advise from my local marine store. Do you guys think the phosphate will start to decline and I just need to be patient?

Quietman · Dec 6, 2019

Not knowing how you cycled (ammonia, fish, dead shrimp or food), hard to say. But 2 ppm isn't a disaster this early with hardly any livestock. Want to manage it to stop any algae but plenty of time. Sure the Rowaphos will work. Don't add too much. Personally, I'd just do another water change or two and start up the skimmer and wait. That phosphate removal media is pretty powerful stuff but again, it's early. If it takes all the phosphate out, you have plenty of time to adjust.

Mical · Dec 6, 2019

Are you using RODI water? Or did your "set up guy" use tap water?

assad319 · Dec 6, 2019

Quietman said:
Not knowing how you cycled (ammonia, fish, dead shrimp or food), hard to say. But 2 ppm isn't a disaster this early with hardly any livestock. Want to manage it to stop any algae but plenty of time. Sure the Rowaphos will work. Don't add too much. Personally, I'd just do another water change or two and start up the skimmer and wait. That phosphate removal media is pretty powerful stuff but again, it's early. If it takes all the phosphate out, you have plenty of time to adjust.

Thanks for the reply.

Did not add anything to begin with. I am assuming the rock I used must have been dirty as ammonia developed quite without me needing to to anything really.

I think I will wait a few days and see what has happened to the phosphate levels.

I don't mind waiting longer at all. Would rather get off to a good start rather than problems.

assad319 · Dec 6, 2019

Mical said:
Are you using RODI water? Or did your "set up guy" use tap water?

RODI water

assad319 · Dec 6, 2019

assad319 said:
RODI water

BUT I remember at the start when we set up the rock he did fill it up with tap water and told me to run it for 2 days before replacing it with RODI. I realise now that probably wasn't the best thing to do!!!!

Quietman · Dec 6, 2019

assad319 said:
Thanks for the reply.

Did not add anything to begin with. I am assuming the rock I used must have been dirty as ammonia developed quite without me needing to to anything really.

I think I will wait a few days and see what has happened to the phosphate levels.

I don't mind waiting longer at all. Would rather get off to a good start rather than problems.

Excellent call. If rock had organics, that could explain your phosphate as well. Wait a while...as long as levels are not increasing, you're good. I'm sure you're aware that if there's too long a delay in feeding tank the baterica will die off without ammonia/nitrite source.

Mical · Dec 6, 2019

assad319 said:
BUT I remember at the start when we set up the rock he did fill it up with tap water and told me to run it for 2 days before replacing it with RODI. I realise now that probably wasn't the best thing to do!!!!

I'm guessing that's where your phosphates are coming from. Your #s aren't critically bad but a couple of healthy water changes would be a start in the right direction and hold off adding any livestock until levels get more inline.