Phosphate levels seem very high

[eliaslikesfish]

Hi all,
I have a 40 gallon live rock only tank, have had it for about 4 months. I have 2 clowns, a midas blenny, and a fire shrimp. They all seem to be thriving, active and eating like champs. I’m hoping to add my first corals, I’m just a little concerned about my phosphate levels. My current parameters are below and have been constant except the phosphate which continues to rise to what seems like an unhealthy level.
Temp: 78F
Ph: 8.2
Salinity: 1.025
Alkalinity: 10dKH (measured with hanna tester)
Ammonia & Nitrites: 0
Nitrate 17.1PPM (measured with Hanna Nitrate HR tester)
Calcium: 380ppm
Phosphates: 0.73ppm (measured with Hanna phosphate ULR checker)
Please let me know any insight you may have.. Based off what I’ve read 0.73ppm phosphate seems real concerning…

Thanks in advance,
Elias

 

[jda]

I think that .73 is pretty high. There are corals that won't mind that level and other that will.

While water changes are great for many things, they won't help much with lowering po4. Media and chemicals are the main ways to lower po4. Most algae methods are better at maintaining.

Read about how aragonite binds po4. It is important to understand that if you remove po4 from the water column, the rock/sand will unbind some and your level will be very near to where you started. You have to keep going and eventually the tank level will lower.

 

[CasperOe]

Could you be overfeeding maybe? Elevated phosphate don't come from nowhere, so you will have to tailor your nutrition input to the available filtration that you have (mechanical / biological / chemical).

Also, thought you had a tang in there as well? They do produce some waste as well..

 

[dank.reefer]

I hope you have already got this sorted but if not, It may be possible that you have elevated silicates. The elevated silicates can cause high readings on some test kits particularly the hanna checker. Try testing with another kit such as the Red Sea pro PO4 kit and verify that your numbers are correct.

Also test your RODI to make sure you are not adding any P04 through the filter. I made both of these mistakes early on and found myself hopelessly chasing phosphates due to adding them through the RODI with exhausted DI resin. I changed out the resin and I am now watching the Po4 and silicates slowly come back down.

Either way keep us posted as to how this gets resolved.