What to use... Phosphates

0 Members and 1 Guest are viewing this topic. 1596 views

  • Posts: 3
  • Liked: 0
  • Thanks Given: 0
  • Received: 0

Hi, I'm currently running an aquareef 195 with Sump with macro algaes, Skimmer, Nyos Phosi Ex in a reactor...

Stocking: 2 Clowns, 2 Chromis and 1 starry blenny, 4 hermits, 2 turbos, conch and emerald crab. I have various corals, zoas, softies, lps and sps.

I dose daily: cal, alk and carbon and carry out 25ltr water changes every single weekend.

My parameters (Salifert and Milwaukee for po4)
Ammonia 0
Nitrite 0
No3 50
po4 0
Alk 10.5
Cal 480
Mag 1410

My problem Is, despite the carbon dosing I have high nitrates but non detectable phosphates which I feel is a false reading because I am having terrible hair algae issues.. I pull the algae off the rocks on a regular basis but within a week it's back again. Since carbon dosing though I go longer between cleaning my glass and my water looks a lot clearer but I'm seeing no reduction in either my nitrates or algae.

The other day a friend recommended I use Continuum Exxodus Nitryx along side the carbon dosing to lower my nitrates but on looking into it a little more I'm thinking that Continuum Exxodus BAC would be better as that combats both Nitrate and Phosphates.

Help please?


  • Andy
  • Global Moderator
  • Posts: 1,046
  • Liked: 266
  • Thanks Given: 176
  • Received: 200
  • Problems: 99
  • Tank Thread: https://reefbase.co.uk/members'-tanks-6/andy's-85l-nano/new/#new

Reply #1

Counter intuitive but you might have to stop your phosphate remover running to get the nitrate reduced.  The bacteria need both to grow.  So if the algae and the PhosEx are stripping the phosphate, the bacteria have nothing to work with.

I've even read before of people dosing potassium phosphate to bring the level up slightly to help things along. 


  • Tim
  • Global Moderator
  • Posts: 2,657
  • Liked: 701
  • Thanks Given: 359
  • Received: 587
  • Location: Camberley
  • Tank Thread: https://reefbase.co.uk/members'-tanks-6/tims-first-and-last-upgrade/msg42396/#msg42396

Reply #2


You have a lot going on there, you don’t sound over stocked wich is good.

How much rock do you have?
How deeps your sand?
How longs it been set up?
How much are you feeding?

Depending on those answers this is what I would do.
Remove the macro algae, it won’t grow very well with nitrate that high so will die and re release nutrients back in to the water. Also if your iron and iodine levels are low that will stunt its growth.
Keep going with the carbon dosing and maybe up the dose, if I know what your dosing and how much I could give you a dosing figure. Keep the skimmer clean and skim very wet, at least a full cup of tea skim a day, make sure to keep a eye on your salinity as very wet skimming can make it drop.
If you get a bacteria bloom you have gone to high with the dose so back it off.
If the nitrates don’t go down the best way to add phosphate is chuck a cube of frozen food in.

I’ve probably missed something so ask any questions



  • Posts: 10
  • Liked: 4
  • Thanks Given: 0
  • Received: 0
  • Location: Farsley

Reply #3

The readings you are getting are not false.  Any tank that's full of algae will read zero phosphates because the algae is using them all up. 

To get rid of algae in the DT you need to do the following:

Get a powerful grow light for the fuge if you haven't already got one.
install a phosphate reactor if you haven't already.
turn off the DT lighting and cover the tank in a blanket if it's in a bright room.

Don't worry about the DT being dark.  The fish couldn't care less and corals will be OK for a few days at a time.  This sounds a bit drastic but it works.


  • Posts: 9
  • Liked: 8
  • Thanks Given: 0
  • Received: 0
  • Location: Cheshire

Reply #4

I was phos limited but nitrates were 50+ I had gha, dinos and cyano........drove me mad.
I got the PO4 upto around 3.0 and then, this brought the nitrates down and the phos with it. Now sitting at about PO4-0.05 and NO3- 15ppm. All the algae etc slowly started to disappear. Now been at these figures for a few months........and no 'orrible green/red stuff.


Related Topics

24 Replies
Last post Apr 12, 2016 9:21:11 pm
by HK_Fuey

Started by Debbiem « 1 2 » Chemistry

15 Replies
Last post May 3, 2016 5:58:24 pm
by HK_Fuey
4 Replies
Last post Sep 13, 2016 12:06:35 am
by HK_Fuey
8 Replies
Last post Sep 27, 2016 6:53:50 pm
by Marty
20 Replies
Last post Oct 9, 2016 2:14:50 pm
by HK_Fuey

Donate towards the running of ReefBase

Donate £1.00 Donate £2.50 Donate £5.00 Donate £10.00 Donate £20.00 Donate another value