High po4, low no3, fuge?

[Bryan68]

So here's my question, I have a180 gallon which is a tank transfer and has been set up for 4 months. currently no3 is very steady at 7ppm, po4 was constantly rising so I started running rowaphos which keeps po4 in check (@ 0.7 ppm). If I were to add a cheato fuge, would it bottom out my no3? Should I keep doing what I'm doing? Possibly a Xenia fuge?
Thanks in advance!

 

[Bryan68]

I should add that diatoms will not go away. Yep, using rodi with 0 TDS.

 

[Bryan68]

Anyone?

 

[Bryan68]

Anyone?

 

[NS Mike D]

1. Can you confirm the are indeed diatoms (and not something else like dinos)
2. Silicate can get through the RODI because if it's very low ionic properties, can be present but read 0 TDS. (I read this, so can someone confirm?) Get a silicates test and check your rodi
3. Cheato can bring down both NO3 and PO4, It't possible to bottom out, but it will usually slow down as they get really low and can be manipulated by light schedule or removing the rowaphos.

 

[Bryan68]

Thanks #NS Mike D, not sure how to confirm it's diatoms. I will say that when it's on the rocks it will blow off like dust, which is what lead me to believe it is diatoms. Additionally, I see zero bubbles in any of the algae. Do you propose a better way of verification? I don't own a microscope. I will look for a silicate test asap, and see what I get.
Could this be part of the ugly phase? I did start this tank with some live rock from my previous setup, but did add a bunch of new dry Marco rock along with dry special grade sand.